JP3925172B2 - Fuel cell module - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solid oxide fuel cell module having a power generation cell configured by sandwiching an electrolyte layer between a fuel electrode layer and an oxidant electrode layer.
[0002]
[Prior art]
Conventionally, as this type of fuel cell, a solid oxide fuel cell described in JP-A-6-13088 has been known. In this solid oxide fuel cell, an assembly composed of a laminate of an anode, a solid electrolyte body, and a cathode, and a separator provided with a reaction gas supply pipe are alternately stacked, and fuel gas is supplied to one surface of the separator. It is described that a groove through which an oxidant gas flows is formed on the other surface of the separator. In this fuel cell, the reaction gas supply pipe is composed of a fuel gas supply pipe and an oxidant supply pipe formed at least in part by a ceramic pipe such as an alumina porcelain pipe. The fuel gas supply pipe is connected to the side of the separator and communicates with the groove through which the fuel gas flows, and the oxidant supply pipe is connected to the side of the separator and is configured to communicate with the groove through which the oxidant gas flows. The The fuel gas supply pipe is connected to a fuel gas distributor made of ceramic, and the oxidant supply pipe is connected to an oxidant gas distributor made of ceramic.
In the solid oxide fuel cell configured as described above, since the reaction gas supply pipe is individually connected to each separator, a circular glass ring that conventionally seals the circular gas manifold formed on the assembly and the separator. In addition, a rectangular glass ring that conventionally gas-sealed the outer shape between the assembly and the separator can be eliminated.
[0003]
[Problems to be solved by the invention]
However, in the solid oxide fuel cell shown in the above-mentioned conventional Japanese Patent Laid-Open No. 6-13088, the ribbed porous substrate of the separation plate is formed with ribs for guiding the reaction gas in a predetermined direction. The surface area of the power generation cell that contributes to power generation is reduced by the contact area of the rib with the anode or cathode, and there is a problem in that power generation efficiency decreases.
Further, in the solid oxide fuel cell disclosed in the above-mentioned conventional JP-A-6-13088, since the anode and cathode and the ribbed porous substrate are in contact with each other only by the rib, Therefore, the reaction is likely to occur only in the vicinity of the portion where the anode and the cathode are in contact with the rib. In other words, since the central portion of the groove between the ribs is not in contact with the anode and the cathode, the electrons generated by the reaction disappear due to the electrical resistance of the anode and the cathode before reaching the rib, and the reaction occurs on the entire surface of the power generation cell. There were also problems that were difficult to make.
Furthermore, in the solid oxide fuel cell shown in the above-mentioned conventional Japanese Patent Laid-Open No. 6-13088, part or all of the reaction gas supply pipe is formed of a relatively brittle ceramic pipe. This has to be done carefully, increasing the assembly time, and possibly causing damage to the reaction gas supply pipe due to thermal stress acting on the reaction gas supply pipe due to repeated heating and cooling of the fuel cell.
[0004]
A first object of the present invention is to provide a fuel cell module capable of improving power generation efficiency by causing all the surfaces of power generation cells contributing to power generation to contribute to power generation.
A second object of the present invention is to provide a fuel cell module capable of uniformly heating and cooling a power generation cell by flowing an oxidant gas substantially uniformly throughout the oxidant electrode layer.
A third object of the present invention is a fuel cell module which can improve the power generation efficiency by controlling the flow of fuel gas in the fuel electrode layer and increasing the number of collisions between the fuel gas and the fuel electrode layer.
A fourth object of the present invention is to provide a fuel cell module that can shorten the temperature raising time at startup and can prevent damage to the power generation cell by uniform temperature raising.
[0005]
A fifth object of the present invention is to provide a fuel cell module that can improve power generation efficiency by supplying fuel gas and oxidant gas to each power generation cell at a temperature suitable for power generation.
A sixth object of the present invention is to join one or both of a fuel electrode current collector and an oxidant electrode current collector to a stainless steel separator, a first end plate, and a second end plate, By welding and preventing oxidation of the joint portion, long-term electrical conduction between the separator, the first end plate or the second end plate and the fuel electrode current collector or the oxidant electrode current collector can be obtained. It is to provide a fuel cell module.
A seventh object of the present invention is to provide a fuel cell module that can reduce the number of components and can be miniaturized by eliminating the need for a reformer for reforming fuel gas. .
[0006]
  As shown in FIGS. 1 and 2, the invention according to claim 1 includes a power generation cell 12 including an electrolyte layer 12a and a fuel electrode layer 12b and an oxidant electrode layer 12c disposed on both surfaces of the electrolyte layer 12a. (N + 1) (n is a positive integer) stacked fuel cell, the fuel electrode layer 12b of the i-th (i = 1, 2,..., N) power generation cell 12 and the fuel electrode layer A total of n separators 16 each formed in a plate shape with a conductive material are interposed between the oxidant electrode layer 12c of the (i + 1) th power generation cell 12 adjacent to 12b, and the i th power generation. Between the fuel electrode layer 12b of the cell 12 and the jth (j = 1, 2,..., N) separator 16, a porous anode current collector 17 having conductivity is interposed, and the (i + 1) th Between the oxidant electrode layer 12 c of the power generation cell 12 and the j-th separator 16. A porous oxidant electrode current collector 18 having a conductive property is interposed, and the oxidant electrode layer 12c of the first power generation cell 12 is formed in a plate shape by a conductive material via the oxidant electrode current collector 18. In addition, a single first end plate 21 is laminated, and a single first end plate 21 is formed on the fuel electrode layer 12b of the (n + 1) th power generation cell 12 with a conductive material via the fuel electrode current collector 17 in a plate shape. The two end plates 22 are stacked, and the n separators 16 introduce fuel gas from the outer peripheral surface of the separator 16 so that the separator 16centerThe fuel supply passage 23 is discharged from the fuel electrode current collector 17 toward the fuel electrode current collector 17, and the oxidant supply is introduced from the outer surface of the separator 16 and discharged from the surface of the separator 16 facing the oxidant electrode current collector 18. Each having a passage 24, and a single first end plate 21 has an oxidant supply passage 27 for discharging the oxidant gas from the surface of the first end plate 21 facing the oxidant electrode current collector 18, A single second end plate 22 delivers fuel gas to the second end plate 22centerA fuel supply passage 26 that discharges from the fuel electrode current collector 18 toward the fuel electrode current collector 18, and a fuel distributor 13 that supplies fuel gas to the fuel supply passages 23 and 26 is provided in the fuel cell 11.With a gap on the sideAn oxidant distributor 14 provided for supplying oxidant gas to the oxidant supply passages 24 and 27 is provided in the fuel cell 11.With a gap on the sideA pair of electrode terminals 41 and 42 are electrically connected to the first end plate 21 and the second end plate 22, respectively.Each of the oxidant supply passages 24 formed in the n separators 16 introduces oxidant gas from the outer peripheral surface of the separator 16 and discharges it in a shower form from the surface of the separator 16 facing the oxidant electrode current collector 18. The oxidant supply passage 27 formed in the single first end plate 21 discharges the oxidant gas from the surface of the first end plate 21 facing the oxidant electrode current collector 18 in a shower shape. ConfiguredThis is a fuel cell module.
[0007]
  In the fuel cell module according to claim 1, when the fuel gas is introduced into the fuel distributor 13, the fuel gas passes through the separator 16 and the fuel supply passages 23 and 26 of the second end plate 22, and the separator 16 and the second Of the two end plates 22centerTo the center of the fuel electrode current collector 17. The discharged fuel passes through the anode current collector 17 and flows from the approximate center of the anode layer 12b toward the outer periphery. At the same time, when the oxidant gas is introduced into the oxidant distributor 13, the oxidant gas passes through the oxidant supply passages 24 and 27 of the separator 16 and the first end plate 21, and passes through the separator 16 and the first end plate 21.centerTo the center of the oxidant electrode current collector 18. The discharged oxidant gas passes through the oxidant electrode current collector 18 and flows along the solid electrolyte layer 11a in the oxidant electrode layer 12c.
  The oxidant gas receives electrons from the oxidant electrode layer 12c in contact with the oxidant electrode current collector 18 over the entire surface of the power generation cell 12, and is ionized into oxide ions. The oxide ions diffuse in the solid electrolyte layer 12a. It moves and reaches the vicinity of the interface with the fuel electrode layer 12b. As a result, the oxide ions react with the fuel gas to produce a reaction product, and electrons are emitted to the fuel electrode layer 12b. Therefore, a large current is generated by taking out these electrons from the entire surface of the fuel electrode current collector 17, Electric power is obtained. The (n + 1) power generation cells 12 are connected in series via a separator 16, a fuel electrode current collector 17, and an air electrode current collector 18 formed of a conductive material, and are formed of a conductive material at both ends. Since the first end plate 21 and the second end plate 22 are provided, large electric power can be taken out from the pair of electrode terminals 41 and 42.
[0008]
acidSince the oxidant gas is discharged almost uniformly from the oxidant supply passages 24 and 27 in the form of a shower toward the oxidant electrode current collector 18, the power generation cell 12 can be uniformly heated and cooled by the oxidant gas. When the power generation cell 12 is heated and rises above a set temperature due to generation of Joule heat during power generation of the fuel cell 11, an oxidant gas having a temperature lower than the set temperature is discharged from the oxidant supply passages 24 and 27. By doing so, the power generation cell 12 can be cooled uniformly, so that damage due to local heating or cooling of the power generation cell 12 can be prevented.
[0009]
  Claim2The invention according to claim1As shown in FIGS. 2 and 3, the n separators 16 are connected to the fuel supply passages 23, 26 and the oxidant supply passages 24, 27 so that the single separator A plurality of insertion holes 16a are formed in one or more of the first end plate 21 and the single second end plate 22, and either the first heater 31 or the temperature sensor or the plurality of insertion holes 16a or Both are inserted.
  This claim2In the fuel cell module described in (1), the temperature of the power generation cell 12 can be quickly raised by energizing the first heater 31 when the fuel cell 11 is started, so that the temperature raising time can be shortened. In addition, since the temperature of the power generation cell 12 is increased uniformly and the temperature difference between the center and the outer periphery of the power generation cell 12 is eliminated and the thermal expansion is performed uniformly, damage to the power generation cell 12 can be prevented. Furthermore, if the first heater is controlled based on the detection output of the temperature sensor, the temperature of the separator or the like can be finely controlled.
[0010]
  Claim3The invention according to claim1The n-type separator, a single first end plate, or a single second end plate so as not to communicate with either the fuel supply passage or the oxidant supply passage. A plurality of lightening holes are formed in two or more.
  This claim3In the fuel cell described in (1), the weight of the separator, the first end plate, or the second end plate can be reduced by forming the weight reduction hole, so that the weight of the fuel cell can be reduced.
[0013]
  Claim4The invention according to claim 1 to claim 13either1 itemFurther, as shown in FIG. 1, a fuel preheating pipe 43 for supplying fuel gas to the fuel distributor 13 is wound around the outer peripheral surface of the fuel cell 11, and the oxidant gas is supplied to the oxidant distributor 14. The oxidant preheating pipe 44 for supplying the fuel is wound around the outer peripheral surface of the fuel cell 11, and the fuel cell 11 is accommodated in the inner case 46 together with the fuel preheating pipe 43 and the oxidant preheating pipe 44 and discharged from the power generation cell 12. An exhaust pipe 51 for discharging gas and oxidant gas out of the inner case 46 is connected to the inner case 46.At least the inner surface of the inner case 46 is silver-plated via silver plating or nickel base plating.It is characterized by that.
  This claim4In the fuel cell module described in 1), the fuel gas passing through the fuel preheating pipe 43 is discharged from the power generation cell 12 at high temperature exhaust gas (water vapor generated from the fuel gas and oxidant gas, CO 2₂) Is supplied to the fuel distributor 13, and the oxidant gas passing through the oxidant preheating pipe 44 is also heated by the high-temperature exhaust gas discharged from the power generation cell 12 and supplied to the oxidant distributor 44. For this reason, since fuel gas and oxidant gas are supplied to each power generation cell 12 at a temperature suitable for power generation, power generation efficiency can be improved.
  Further, by utilizing the radiant heat generated by the power generation cell 12 during the operation of the fuel cell 11, the heat retention effect of the power generation cell 12 and the separator 16 can be further enhanced.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the fuel cell module 10 includes a fuel cell 11 having (n + 1) power generation cells 12 stacked, a single fuel distributor 13 and a single fuel cell 11 provided in the vicinity of the fuel cell 11. And an air distributor 14 (oxidant distributor). Here, n is a positive integer. The power generation cell 12 includes a disk-shaped solid electrolyte layer 12a, and disk-shaped fuel electrode layers 12b and air electrode layers 12c (oxidant electrode layers) disposed on both surfaces of the solid electrolyte layer 12a. There is electrical conduction between the fuel electrode layer 12b of the i-th (i = 1, 2,..., n) power generation cell 12 and the air electrode layer 12c of the (i + 1) th power generation cell 12 adjacent to the fuel electrode layer 12b. A total of n separators 16 each having a square plate shape made of a conductive material are interposed. A porous fuel electrode is formed between the fuel electrode layer 12b of the i-th power generation cell 12 and the j-th (j = 1, 2,..., N) separator 16 and has a conductive shape. A current collector 17 is interposed between the air electrode layer 12c of the (i + 1) th power generation cell 12 and the jth separator 16, and is formed into a disk shape and has a conductive porous air electrode collection. An electric body 18 (oxidant electrode current collector) is interposed. Furthermore, a single first end plate 21 formed in a square plate shape with a conductive material is laminated on the air electrode layer 12c of the first power generation cell 12 via the air electrode current collector 18, and the (n + 1) th A single second end plate 22 formed in a square plate shape with a conductive material is stacked on the fuel electrode layer 12 b of the power generation cell 12 via the fuel electrode current collector 17.
[0031]
The solid electrolyte layer, the fuel electrode layer, the air electrode layer, the fuel electrode current collector, and the air electrode current collector are not in the shape of a disk, but a polygonal plate such as a quadrangular plate, a hexagonal plate, or an octagonal plate. You may form in a shape. Further, the separator, the first end plate and the second end plate may be formed in a polygonal plate shape such as a disc shape, a rectangular plate shape, a hexagonal plate shape, an octagonal plate shape, etc. instead of a square plate shape. . In this case, in order to allow the fuel gas to flow evenly from the approximate center of the power generation cell 12, the number of second fuel holes 23b of the fuel supply passage 23 to be described later is not limited to one, but two or three at the approximate center. It may be the above.
[0032]
In addition, when the fuel cell is installed so that the stacking direction of the power generation cells coincides with the vertical direction, that is, each power generation cell extends in the horizontal direction, the fuel gas is preferably discharged from the substantially center of the separator. When the fuel cell is installed so that the stacking direction of the fuel cell coincides with the horizontal direction, that is, each power generation cell extends in the vertical direction, it is preferable that the fuel gas is discharged from a portion shifted slightly below the center of the separator. . The reason for this is that when fuel cells are installed so that each power generation cell extends in the vertical direction, when hydrogen or methane fuel gas is discharged from the center of the separator, hydrogen or methane rises due to the effect of gravity, This is because the battery reaction is more active in the upper part of the power generation cell than in the lower part. Therefore, when the fuel cell is installed so that each power generation cell extends in the vertical direction, the position of the second fuel hole is shifted slightly below the center of the separator in order to generate power uniformly over the entire surface of the power generation cell as described above. Is preferred.
[0033]
Further, when the third air holes 24c of the air supply passage 24, which will be described later, are formed in a shower shape (in a state where a large number of them are arranged in the vertical and horizontal directions) It is preferable to form many (closely) third air holes 24c in the portion. This is because if the shower-like third air holes 24 c are formed at equal intervals, more air is discharged from the outer peripheral portion than the central portion of the separator 16.
[0034]
The solid electrolyte layer 12a is formed of an oxide ion conductor. Specifically, it is an oxide ion conductor represented by the general formula (1): Ln1AGaB1B2B3O. However, in the said General formula (1), Ln1 is 1 type, or 2 or more types of elements chosen from the group which consists of La, Ce, Pr, Nd, and Sm, Comprising: 43.6-51.2 weight% is contained. , A is one or more elements selected from the group consisting of Sr, Ca and Ba, and is contained in an amount of 5.4 to 11.1% by weight, and Ga is contained in an amount of 20.0 to 23.9% by weight. B1 is one or more elements selected from the group consisting of Mg, Al and In, and B2 is one or more elements selected from the group consisting of Co, Fe, Ni and Cu. B3 is one or more elements selected from the group consisting of Al, Mg, Co, Ni, Fe, Cu, Zn, Mn, and Zr, and B1 and B3 or B2 and B3 are respectively When they are not the same element, B1 is included in 1.21 to 1.76% by weight, and B2 is .84 to 1.26 wt% contained, B3 contained 0.23 to 3.08 wt%, and when B1 and B3 or B2 and B3 are the same element, the contents of B1 and B3 Is 1.41 to 2.70% by weight, and the total content of B2 and B3 is 1.07 to 2.10% by weight.
[0035]
Moreover, the solid electrolyte layer 12a is made into General formula (2): Ln1_1-xA_xGa_1-yzwB1_yB2_zB3_wO_3-dYou may form with the oxide ion conductor shown by these. In the general formula (2), Ln1 is one or more elements selected from the group consisting of La, Ce, Pr, Nd and Sm, and A is a group consisting of Sr, Ca and Ba. One or more elements selected from B1, B1 is one or more elements selected from the group consisting of Mg, Al and In, and B2 is Co, Fe, Ni and One or two or more elements selected from the group consisting of Cu, wherein B3 is one or two elements selected from the group consisting of Al, Mg, Co, Ni, Fe, Cu, Zn, Mn and Zr X is 0.05 to 0.3, y is 0.025 to 0.29, z is 0.01 to 0.15, w is 0.01 to 0.15, and y + z + w 0.035-0.3 and d are 0.04-0.3. By forming the solid electrolyte layer 12a from the oxide ion conductor as described above, the power generation operation can be performed at a relatively low temperature of 650 ± 50 ° C. without reducing the power generation efficiency of the fuel cell 11. Become.
[0036]
The fuel electrode layer 12b is made of a metal such as Ni, or is made of a cermet such as Ni-YSZ, or Ni and the general formula (3): Ce_1-m D_m O₂It is formed porous by a mixture with a compound represented by: However, in the said General formula (3), D is 1 type, or 2 or more types of elements chosen from the group which consists of Sm, Gd, Y, and Ca, m is an atomic ratio of D element, 0.05 It is set in the range of -0.4, preferably 0.1-0.3.
[0037]
The air electrode layer 12c has the general formula (4): Ln2_1-x Ln3_x E_1-y Co_y O_{3 + d}It is formed porous by the oxide ion conductor shown by. However, in the said General formula (4), Ln2 is an element of either one or both of La or Sm, Ln3 is an element of either one or both of Ba, Ca, or Sr, E is Fe or Cu. Either one or both elements. X is an atomic ratio of Ln3, and is set in a range of more than 0.5 and less than 1.0. y is an atomic ratio of Co element, and is set in the range of more than 0 and 1.0 or less, preferably 0.5 or more and 1.0 or less. d is set in the range of −0.5 or more and 0.5 or less.
[0038]
An example of a method for manufacturing the power generation cell 12 is shown below. First, as raw material powder, La₂O_Three, SrCO_Three, Ga₂O_ThreeLa, MgO and CoO powders_0.8Sr_0.2Ga_0.8Mg_0.15Co_0.05O_2.8After being weighed and mixed so as to become a pre-fired body at 1100 ° C., a calcined body is produced. Next, after pulverizing the calcined body, a predetermined binder, a solvent, and the like are added and mixed to prepare a slurry, and a green sheet is produced from the slurry by a doctor blade method. Next, this green sheet is sufficiently dried in air, cut out to a predetermined size, and then sintered at 1450 ° C. to obtain the solid electrolyte layer 12a. On one surface of the solid electrolyte layer 12a, Ni and (Ce_0.8Sm_0.2) O₂NiO powder and (Ce_0.8Sm_0.2) O₂After mixing with the powder, this mixed powder is baked at 1100 ° C. to form the fuel electrode layer 12b. Further, on the other surface of the solid electrolyte layer 12a (Sm_0.5Sr_0.5CoO_ThreeIs baked at 1000 ° C. to form the air electrode layer 12c. In this way, the power generation cell 12 is manufactured.
[0039]
The separator 16 is preferably formed of any of stainless steel, nickel base alloy, or chromium base alloy. Examples include SUS316, Inconel 600, Hastelloy X (trade name of Haynes Stellite), Haynes Alloy 214, and the like. The separator 16 is formed with a fuel supply passage 23, an air supply passage 24 (oxidant supply passage), and a plurality of insertion holes 16a (FIGS. 2 and 3). The fuel supply passage 23 includes a first fuel hole 23 a that extends from the outer peripheral surface of the separator 16 toward the center, a second fuel hole 23 b that communicates with the first fuel hole 23 a and faces the anode current collector 17 from the approximately center of the separator 16. Have The air supply passage 24 is formed to extend in a direction orthogonal to the thickness direction of the separator 16, has a substantially T-shaped first air hole 24 a having a base end opened on the outer peripheral surface of the separator 16 and closed at the tip, and a separator A plurality of second air holes 24b extending in a direction perpendicular to the thickness direction of the 16 and spaced apart from each other and communicating with the first air holes 24a and closed at both ends; A plurality of third air holes 24c are formed on the surface facing the electric body 18 so as to be spaced from each other and communicate with the second air holes 24b.
[0040]
The first air hole 24a includes a base hole 24d having the same hole core as the first fuel hole 23a, and a distribution hole 24e communicating with the base hole 24d and communicating with the plurality of second air holes 24b and closed at both ends. . The distribution hole 24e is formed so as to be orthogonal to the base hole 24d from the side surface adjacent to one side surface of the separator 16 in which the base end of the base hole 24d is formed, and then the closing plate 25 is joined to the adjacent side surface. It becomes a long hole with both ends closed. The plurality of second air holes 24b are formed in parallel to the base hole 24d from one side surface of the separator 16 in which the base end of the base hole 24d is formed, and then both ends are closed by joining a closing plate 25 to the side surface. It becomes a plurality of elongated holes. The plurality of insertion holes 16a are formed in parallel to the first fuel hole 23a and the second air hole 24b so as not to communicate with either the fuel supply passage 23 or the air supply passage 24, and the first heater is provided in the insertion holes 16a. 31 are respectively inserted (FIG. 3). Further, three slits 16b are formed in a spiral shape from the substantially center of the separator 16 on the surface of the separator 16 facing the fuel electrode current collector 17 (FIG. 4), and the depth of these slits 16b is the same over the entire length. It is formed to become. Note that the number of slits is not three, but may be two or four or more. Moreover, you may form so that the depth of a slit may become deeper or shallower as it leaves | separates from the center of a separator.
[0041]
Returning to FIG. 2, the anode current collector 17 is made of stainless steel, nickel-base alloy or chromium-base alloy, or made of nickel, silver, silver alloy, platinum or copper, and is made of stainless steel, nickel-base alloy or chromium. When formed from a base alloy, it is preferable to perform silver plating or copper plating via nickel plating, silver plating, nickel base plating. The air electrode current collector 18 is made of stainless steel, silver-plated or platinum-plated stainless steel via nickel plating, nickel base plating, nickel-base alloy or chromium-base alloy, or silver, silver alloy or platinum. When formed with a nickel-base alloy or a chromium-base alloy, it is preferable to perform silver plating, silver plating via nickel base plating, or platinum plating. When hydrocarbon is used as the fuel gas, the anode current collector is formed of nickel-plated stainless steel, nickel-base alloy or chromium-base alloy, or nickel, and when hydrogen is used as the fuel gas. The anode current collector is formed of silver-plated, silver-plated or copper-plated stainless steel via nickel base plating, nickel-based alloy or chromium-based alloy, or silver, silver alloy, platinum or copper. An example of a method for producing the fuel electrode current collector 13 will be described below. First, after kneading an atomized powder such as stainless steel and HPMC (water-soluble resin binder), distilled water and additives (n-hexane (organic solvent), DBS (surfactant), glycerin (plasticizer), etc.) are added. In addition, a mixed slurry is prepared by kneading. Next, a molded body is produced from this mixed slurry by the doctor blade method, and then foamed, degreased and sintered under predetermined conditions to obtain a porous plate. Further, this porous plate is cut out to a predetermined size to produce the fuel electrode current collector 17. In addition, when the atomized powder of stainless steel is used, the surface is subjected to silver plating through nickel plating, chromium plating, silver plating, or nickel base plating. The air electrode current collector 18 is also produced in substantially the same manner as the fuel electrode current collector 17.
[0042]
The first end plate 21 and the second end plate 22 are formed in the same shape (square plate shape) from the same material as the separator 16. The first end plate 21 is formed with an air supply passage 27 and a plurality of insertion holes (not shown), and the second end plate 22 is formed with a fuel supply passage 26 and a plurality of insertion holes (not shown). . The air supply passage 27 is formed in the same manner as the air supply passage 23, is formed to extend in a direction perpendicular to the thickness direction of the first end plate 21, has a proximal end opened to the outer peripheral surface of the first end plate 21, and a distal end closed. The T-shaped first air hole 27a and the first end plate 21 extending in a direction perpendicular to the thickness direction and spaced from each other are communicated with the first air hole 27a and further closed at both ends. A plurality of second air holes (not shown) and a surface of the first end plate 21 facing the air electrode current collector 14 are spaced apart from each other and communicated with the second air holes. A number of third air holes (not shown). The fuel supply passage 26 is formed in the same manner as the fuel supply passage 23, and communicates with the first fuel hole 26a from the outer peripheral surface of the second end plate 22 toward the center and the first fuel hole 26a. And a second fuel hole 26b facing the fuel electrode current collector 13 from substantially the center.
[0043]
The first air hole 27a formed in the first end plate 21 includes a base hole 27d and a distribution hole 27e which communicates with the base hole 27d and communicates with a plurality of second air holes and closed at both ends. The distribution hole 27e is formed so as to be orthogonal to the base hole 24d from the side surface adjacent to one side surface of the first end plate 21 in which the base end of the base hole 27d is formed, and then the closing plate 25 is joined to the adjacent side surface. By doing so, it becomes a long hole whose both ends are closed. The plurality of second air holes are formed in parallel to the base hole 27d from one side surface of the first end plate 21 in which the base end of the base hole 24d is formed, and then both ends are closed by joining a closing plate to the side surface. It becomes a plurality of elongated holes. The plurality of insertion holes of the first end plate 21 are formed in parallel to the second air holes so as not to communicate with the air supply passage 27, and heaters (not shown) are respectively inserted into these insertion holes. The plurality of insertion holes of the second end plate 22 are formed in parallel to the first fuel holes 26a so as not to communicate with the fuel supply passage 26, and heaters (not shown) are respectively inserted into these insertion holes. Three slits 22b are formed in a spiral shape from the approximate center of the second end plate 22 on the upper surface of the second end plate 22, that is, the surface of the second end plate 22 facing the anode current collector 13 (see FIG. 2). These slits 22b are formed to have the same depth over the entire length. Note that the number of slits is not three, but may be two or four or more. Moreover, you may form so that the depth of a slit may become deeper or shallower as it leaves | separates from the center of a separator.
[0044]
Further, through holes 16c into which bolts (not shown) can be inserted are formed at the four corners of the separator 16, the first end plate 21 and the second end plate 22 (FIGS. 3 and 4). (N + 1) power generation cells 12, n separators 16, (n + 1) fuel electrode current collectors 17, (n + 1) air electrode current collectors 18, and a single first end plate 21 and a single second end plate 22, after inserting bolts into the through holes 16 c formed at the four corners of the separator 16, the first end plate 21 and the second end plate 22, By screwing nuts to the ends of these bolts, the fuel cell 11 is fixed in the stacked state.
[0045]
Returning to FIG. 1, the fuel distributor 13 and the air distributor 14 are formed in a cylindrical shape extending in the stacking direction of the power generation cells 12 and closed at both ends. The fuel distributor 13 passes through (n + 1) short fuel pipes 28 and the first fuel holes 23 a of the fuel supply passages 23 of the n separators 16 and the first fuel holes 26 a of the single second end plate 22. The air distributor 14 communicates with each of the fuel holes 26a, and the air distributor 14 passes through the (n + 1) short air tubes 29 and the first air holes 24a of the air supply passages 24 of the n separators 16 and the single first air holes 24a. The end plates 21 are connected to the first air holes 27a of the air supply passages 27 of the end plates 21, respectively. In this embodiment, the fuel distributor 13, the air distributor 14, the fuel short pipe 28, and the air short pipe 29 are formed of a conductive material such as stainless steel, a nickel base alloy, or a chromium base alloy.
[0046]
In order to ensure electrical insulation between the fuel short tube 28 and the fuel distributor 13, the fuel insulation formed of an electrically insulating material such as alumina is provided between the fuel short tube 28 and the fuel distributor 13. A pipe 36 is interposed, and these gaps are sealed by a fuel sealing member 37 having electrical insulating properties such as glass or cement. Further, in order to ensure electrical insulation between the air short pipe 29 and the air distributor 14, the air short pipe 29 and the air distributor 14 are made of an air insulating material such as alumina. An insulating tube 38 is interposed, and these gaps are sealed by an air sealing member 39 having electrical insulation properties such as glass and cement.
[0047]
A pair of electrode terminals 41 and 42 (electrode bars in this embodiment) are electrically connected to the center of the upper surface of the first end plate 21 and the center of the lower surface of the second end plate 22, respectively. A fuel preheating pipe 43 is connected to the upper outer peripheral surface of the fuel distributor 13. The fuel preheating pipe 43 is spaced from the outer peripheral surface of the fuel cell 11 by a predetermined distance and is centered on the axis of the pair of electrode terminals 41, 42. It is wound in a spiral. An air preheating tube 44 (oxidant preheating tube) is connected to the outer peripheral surface of the air distributor 14, and the air preheating tube 44 is spaced from the outer peripheral surface of the fuel cell 11 by a predetermined distance and a pair of electrode terminals 41, 42. It is wound in a spiral shape centered on the axis. Further, the second heater 32 is wound around the outer peripheral surface of the fuel cell 11 in a spiral shape with a predetermined distance from the outer peripheral surface of the fuel cell 11 and centering on the axis of the pair of electrode terminals 41 and 42. The spiral radius of the fuel preheating tube 43 is smaller than the spiral radius of the air preheating tube 44, and the spiral radius of the second heater 32 is a value intermediate between the spiral radius of the fuel preheating tube 43 and the spiral radius of the air preheating tube 44. Formed to be.
[0048]
In this embodiment, the fuel preheating tube 43 and the air preheating tube 44 are formed of stainless steel, a nickel base alloy, a chromium base alloy, or the like. The air preheating pipe 44 is connected to the approximate center in the longitudinal direction of the air distributor 14. This is because Joule heat is generated by the internal resistance of the fuel cell 11 during power generation, and the central portion in the stacking direction of the fuel cell 11 becomes the hottest, and this portion passes through the air preheating pipe 44 and the air distributor 14 relatively. This is to maintain the soaking of the power generation cell 12 by supplying the oxidant gas at a low temperature.
[0049]
The fuel cell 11 is accommodated in an inner case 46 together with a spiral fuel preheating tube 43, a spiral air preheating tube 44 and a spiral second heater 32. A first exhaust pipe 51 and a second exhaust pipe 52 that guide the fuel gas and air discharged from the power generation cell 12 to the outside of the inner case 46 are connected to the lower outer peripheral surface and the upper surface of the inner case 46, respectively. The outer surface of the inner case 46 is covered with a heat insulating material 47, and the fuel preheating pipe 43, the air preheating pipe 44, and the first exhaust pipe 51 are spirally wound around the outer peripheral surface of the inner case 46. In this embodiment, the first exhaust pipe 51 is formed to have a larger diameter than the fuel preheating pipe 43 and the air preheating pipe 44, and the outer periphery of the inner case 46 with the fuel preheating pipe 43 and the air preheating pipe 44 being loosely inserted therein. It is wound spirally at a predetermined interval from the surface. Note that the fuel preheating pipe and the air preheating pipe are not loosely inserted into the first exhaust pipe, but may be spirally wound around the outer peripheral surface of the inner case while being in close contact with the outer peripheral face of the first exhaust pipe. Good.
[0050]
The inner case 46 is accommodated in the outer case 48 together with the spiral first exhaust pipe 51, the fuel preheating pipe 43 and the air preheating pipe 44 loosely inserted in the first exhaust pipe 51, and the heat insulating material 47. The first exhaust pipe 51, together with the fuel preheating pipe 43 and the air preheating pipe 44 loosely inserted into the first exhaust pipe 51, protrudes from the upper outer peripheral surface of the outer case 48 to the outside of the outer case 48, and the fuel preheating pipe 43 and the air The preheating pipe 44 protrudes outside the first exhaust pipe 51 from the protruding portion. A fuel preheating pipe 43 protruding from the first exhaust pipe 51 is inserted with a tip of a water supply pipe 49 for mixing water vapor with the fuel gas in the fuel preheating pipe 43. Not shown) is connected. The distal end of the water supply pipe 49 is preferably located in the outer case 48. As the fuel gas, for example, methane gas (CH_Four)). Although not shown, the mist-like water ejected from the sprayer is vaporized by the heat of the exhaust gas passing through the second exhaust pipe 52 to become water vapor. The fuel preheating tube 43 is filled with reforming particles (not shown) at a density at which the fuel gas can flow. These modified particles are Ni, NiO, Al₂O_Three, SiO₂, MgO, CaO, Fe₂O_Three, Fe_ThreeO_Four, V₂O_ThreeNiAl₂O_Four, ZrO₂, SiC, Cr₂O_Three, ThO₂, Ce₂O_Three, B₂O_Three, MnO₂, ZnO, Cu, BaO and TiO₂It is preferably formed of an element or oxide containing one or more selected from the group consisting of:
[0051]
A water separator 53 is connected to the lowermost end of the fuel preheating pipe 43 wound spirally around the fuel cell 11 and located in the inner case 46. This is configured such that when the fuel cell module 10 is stopped and the temperature is lowered and the water vapor is liquefied to become water, this water is accumulated in the water separator 53. As a result, even if the fuel cell module 10 is restarted, water is not supplied to the power generation cell 12 in a liquid state, so the performance of the power generation cell 12 does not deteriorate and the power generation cell 12 is not damaged. The water separator may be connected to a fuel preheating pipe outside the inner case.
[0052]
A cooling pipe 56 capable of supplying cooling air (cooling oxidant gas) to the air preheating pipe 44 is disposed at the upper end of the air preheating pipe 44 spirally wound around the fuel cell 11 and located in the inner case 46. Connected. A mixing unit for mixing the air in the air preheating pipe 44 and the cooling air in the cooling pipe 56 is connected between the connection part of the cooling pipe 56 and the connection part of the air distributor 14 in the air preheating pipe 44. Is done. Although not shown in the drawing, a baffle plate, a stirrer and the like are incorporated in the mixing unit to mix the air and the cooling air. A temperature sensor 58 for detecting the temperature of the fuel cell 11 is inserted in the fuel cell 11, and a flow rate adjusting valve 59 for adjusting the flow rate of the cooling air is provided in the cooling pipe 56. The detection output of the temperature sensor 58 is connected to a control input of a controller (not shown), and the control output of the controller is connected to a flow rate adjustment valve 59. Reference numeral 54 in FIG. 1 denotes an insulating ring for electrically insulating the inner case 46 and the outer case 48 from the pair of electrode terminals 41 and 42.
[0053]
The operation of the fuel cell module 10 configured as described above will be described.
Fuel gas (for example, methane gas (CH_Four)) Is supplied to the fuel preheating pipe 43 and water (H₂O) is supplied from the water supply pipe 49 to the fuel preheating pipe 43 to form water vapor, which is mixed with the fuel gas. On the other hand, air (oxidant gas) is supplied to the air preheating pipe 44. The fuel gas containing water vapor is heated at a high temperature in the fuel preheating pipe 43 inserted into the first exhaust pipe 51 around the outer peripheral surface of the inner case 46 (fuel gas and oxidant discharged from the power generation cell 12). The air is heated by exchanging heat with the gas mixture), and the air exchanges heat with high-temperature exhaust gas while spirally rotating around the outer peripheral surface of the inner case 46 in the air preheating pipe 44 inserted into the first exhaust pipe 51. It is heated by doing. Further, since the first exhaust pipe 51 in which the fuel preheating pipe 43 and the air preheating pipe 44 are loosely inserted is covered with a heat insulating material 47, the exhaust gas passing through the first exhaust pipe 51 is difficult to cool.
[0054]
The fuel gas and air heated while spiraling around the outer peripheral surface of the inner case 46 exit from the first exhaust pipe 51 and spirally travel around the outer peripheral surface of the fuel cell 11 when entering the inner case 46. At this time, the fuel gas passing through the fuel preheating pipe 43 is heated by the high-temperature exhaust gas discharged from the power generation cell 12 and the second heater 32. Since the fuel preheating pipe 43 is filled with reforming particles, the fuel gas containing water vapor is reformed by the reforming particles by heating the fuel gas containing water vapor as described above (for example, , Hydrogen gas (H₂). And supplied to the fuel distributor 13. The air passing through the air preheating pipe 44 is also heated by the high-temperature exhaust gas and the second heater 32 and supplied to the air distributor 14.
[0055]
When the fuel gas heated and reformed to an optimum temperature for power generation is introduced into the fuel distributor 13, the fuel gas passes through the fuel short pipe 28 and the fuel supply passages 23, 26, and the separator 16 and the second end plate. The fuel is discharged from approximately the center of 22 toward the center of the fuel electrode current collector 17. As a result, the fuel gas passes through the pores in the fuel electrode current collector 17 and is quickly supplied to the approximate center of the fuel electrode layer 12b, and is further guided by the slits 16b and 22b to the outer periphery from the approximate center of the fuel electrode layer 12b. It flows in a spiral toward. At the same time, when air heated to an optimum temperature for power generation is introduced into the air distributor 14, this air passes through the air short pipe 29 and the air supply passages 24, 27, and passes through the third air holes 24 c and the second air holes 24 c of the separator 16. From the many 3rd air holes of the 1 end plate 21, it discharges toward the air electrode collector 18 in the shape of a shower. As a result, the air passes through the pores in the air electrode current collector 18 and is supplied to the air electrode layer 11c substantially uniformly.
[0056]
The air supplied to the air electrode layer 12c reaches the vicinity of the interface with the solid electrolyte layer 12a through the pores in the air electrode layer 12c, and oxygen in the air receives electrons from the air electrode layer 12c in this part, Oxide ion (O^2-) Is ionized. The oxide ions diffuse and move in the solid electrolyte layer 12a in the direction of the fuel electrode layer 12b. When the oxide ions reach the vicinity of the interface with the fuel electrode layer 12b, the oxide ions react with the fuel gas in this portion to react with the reaction product (for example, , H₂O) is generated, and electrons are emitted to the fuel electrode layer 12b. When these electrons are taken out by the fuel electrode current collector 17, a current is generated and electric power is obtained. As described above, since the fuel gas is discharged from the approximate center of the separator 16 and the approximate center of the second end plate 22 and is guided by the slits 16b and 22b, the reaction path of the fuel gas becomes long. As a result, since the fuel gas collides with the fuel electrode layer 12b very much before the fuel gas reaches the outer peripheral edge of the separator 16 and the second end plate 22, the number of reactions increases and the performance of the fuel cell 11 is improved. Can be planned. Therefore, the larger the outer diameters of the separator 16 and the second end plate 22 are, the longer the reaction path of the fuel gas becomes. As a result, the number of reactions increases and the output of the fuel cell 11 is improved. Note that (n + 1) power generation cells 12 are connected in series via a separator 16, a fuel electrode current collector 17, and an air electrode current collector 18 formed of a conductive material, and the first and second power cells 12 at both ends of the fuel cell 11 are connected. Since the pair of electrode terminals 41 and 42 are provided on the first end plate 21 and the second end plate 22, large electric power can be taken out from these electrode terminals 41 and 42.
[0057]
Compared with a conventional fuel cell, that is, a fuel cell having a structure not having an air electrode current collector and a fuel electrode current collector, in which a reaction occurs only in the vicinity of the portion where the anode and the cathode are in contact with each other and power generation efficiency is reduced. In the fuel cell module 10 of the present invention, since the entire surface of the power generation cell 12 contributes to power generation, the power generation efficiency is improved.
Further, when the fuel cell module 10 is activated, the power generation cell 12 can be quickly heated by energizing the first heater 31, so that the temperature increase time can be shortened, and the power generation cell 12 is uniformly heated, thereby generating the power generation cell 12. Since the temperature difference between the center and the outer peripheral edge of the battery is eliminated and the heat expands uniformly, damage to the power generation cell 12 can be prevented. When the heater is not inserted into the insertion hole, that is, when the insertion hole is made lighter, the weight of the separator, the first end plate, and the second end plate can be reduced, so that the weight of the fuel cell can be reduced. Can do.
[0058]
Further, the inner case 46 and the inner surface of the outer case 48 are silver-plated, silver-plated or platinum-plated via nickel base plating, and further the fuel short pipe 28, the fuel distributor 13, the fuel preheating pipe 43, and air The outer surfaces of the short tube 29, the air distributor 14 and the air preheating tube 44 are preferably subjected to silver plating, silver plating via nickel base plating or platinum plating. As a result, the radiant heat generated by the power generation cell 12 during operation of the fuel cell 11 can be used to keep the fuel preheating pipe 43 and the oxidant preheating pipe 44 warm, and the heat insulation effect of the power generation cell 12 and the separator 16 can be enhanced. .
The fuel preheating pipe 43, the fuel distributor 13, the fuel short pipe 28, the oxidant preheating pipe 44, the oxidant distributor 14 and the oxidant short pipe 27 are made of stainless steel, nickel-base alloy or chromium-base alloy. Preferably, the inner surface is formed and subjected to silver plating, silver plating or nickel plating via nickel base plating. Thereby, the insides of the oxidant preheating tube 44, the oxidant distributor 14 and the oxidant short tube 27 are not oxidized, and the generation of oxide scale (powdered oxide) can be suppressed. On the other hand, although water vapor exists inside the fuel preheating pipe 43, the fuel distributor 13 and the fuel short pipe 28, which are reducing atmospheres, generation of oxide scale due to the water vapor can be suppressed.
Further, it is preferable that nickel plating is applied to the inner surfaces of the fuel preheating pipe 43, the fuel distributor 13 and the fuel short pipe 28. As a result, the hydrocarbon reforming reaction can be performed inside the fuel preheating pipe 43, the fuel distributor 13, and the fuel short pipe 28.
[0059]
On the other hand, since a large number of third air holes 24c are formed side by side at a predetermined interval on the lower surface of the separator 16 and the lower surface of the first end plate 21, air is supplied to the lower surface of the separator 16 and the first end plate 21. The liquid is discharged from the lower surface of the nozzle substantially uniformly. As a result, the power generation cell 12 can be uniformly heated and cooled by the air. In particular, when the power generation cell 12 is heated and rises above a set temperature (for example, 650 ° C.) due to generation of Joule heat during power generation of the fuel cell module 10, a temperature slightly lower than the set temperature (for example, 630). Since the power generation cell 12 can be uniformly cooled by discharging the air from the air supply passages 24 and 27, damage due to local heating or cooling of the power generation cell 12 can be prevented. The temperature control of the fuel cell 11 described above can be performed by controlling the flow rate adjustment valve 59 of the controller based on the detection output of the temperature sensor 58. That is, when the temperature sensor 58 detects that the fuel cell 11 has exceeded a set temperature (for example, 650 ° C.) during operation of the fuel cell 11, the controller opens the flow rate adjustment valve 59 based on the detection output of the temperature sensor 58. The temperature is changed, the cooling air passing through the cooling pipe 56 is mixed with the air passing through the air preheating pipe 44, and air having a temperature lower than the set temperature (for example, 630 ° C.) is supplied to the fuel cell 11.
[0060]
Further, stainless steel, nickel-base alloy or chromium-base alloy separator 16 and second end plate 22 are subjected to nickel plating, silver plating, silver plating or nickel plating via nickel base plating, stainless steel, nickel base A fuel electrode current collector 17 made of an alloy, a chromium base alloy, nickel, silver, a silver alloy, platinum, or copper is bonded to each other, and a separator 16 and a second end plate 22 made of stainless steel, a nickel base alloy, or a chromium base alloy are joined. Stainless steel, nickel-base alloy, chromium-base alloy, or silver, silver alloy, or platinum air current collector 18 that is silver-plated, silver-plated via platinum plating or platinum-plated, or silver, silver alloy, or platinum are respectively joined to the lower surface. For example, even if the separator 16 and the first end plate 21 are exposed to air at a high temperature, that is, the separator 16 and the first end plate 21 are high. Even when exposed to an oxidizing atmosphere, the joining portion of the separator 16 and the air electrode current collector 18 and the welded joining portion of the first end plate 22 and the air electrode current collector 18 are welded. The oxidation of the part can be prevented. As a result, not only the electrical continuity between the separator 16 and the fuel electrode current collector 17 and the electrical continuity between the second end plate 22 and the fuel electrode current collector 17, but also the electrical conductivity between the separator 16 and the air electrode current collector 18. The continuity and electrical continuity between the first end plate 21 and the air electrode current collector 18 can be maintained for a long time through the joint portion, and the assembling work time of the fuel cell module 10 can be shortened by the joining to improve the assembling workability. it can. In addition, as said joining method, silver brazing, spot welding, laser welding, etc. are mentioned. Further, if the separator 16 made of stainless steel, nickel base alloy or chromium base alloy, the first end plate 21 and the second end plate 22 are subjected to nickel plating, chromium plating, silver plating or silver underplating, the separator 16, the electrical continuity between the first end plate 21 and the second end plate 22, and the fuel electrode current collector 17 and the air electrode current collector 18 can be maintained for a longer period of time.
[0061]
In the above embodiment, air is used as the oxidant gas, but oxygen or other oxidant gas may be used.
In the above embodiment, as the fuel cell, a solid oxide fuel cell in which the power generation cell is configured by sandwiching the solid electrolyte layer between the fuel electrode layer and the air electrode layer (oxidant electrode layer) is described. However, a polymer electrolyte fuel cell, a carbonate molten salt fuel cell, a phosphoric acid fuel cell, or the like may be used.
Moreover, in the said embodiment, although the separator was formed with any of stainless steel, nickel base alloy, or chromium base alloy, lanthanum chromite (La_0.9Sr_0.1CrO_Three) Or the like may be formed of a conductive ceramic.
Moreover, in the said embodiment, although the 1st heater was inserted in the insertion hole of a separator, a 1st end plate, and a 2nd end plate, respectively, a 1st heater and a temperature sensor (thermocouple for temperature measurement) are inserted alternately. May be. In this case, the temperature of the separator or the like can be finely controlled by controlling the first heater based on the detection output of the temperature sensor.
[0062]
In the above embodiment, the tip of the water supply pipe is inserted into the fuel preheating pipe, and the sprayer is connected to the water supply pipe. However, the tip of the water supply pipe is inserted above the fuel preheating pipe, and this water supply A pump may be connected to the proximal end of the tube. In this case, the water supplied to the fuel preheating pipe is vaporized as it goes down the fuel preheating pipe by the heat of the exhaust gas passing through the second exhaust pipe.
Furthermore, exhaust pipes 51 and 52 that guide the fuel gas and the oxidant gas discharged from the power generation cell 12 to the outside of the inner case 46 and the outer case 48 may be connected to the steam turbine. In this case, the high-temperature exhaust gas discharged from the fuel cell module 10 is used to heat water, generate compressed steam, and inject and rotate the compressed steam to the turbine, thereby rotating the generator to generate heat. Energy can be converted to electrical energy.
[0063]
【The invention's effect】
As described above, according to the present invention, one separator is interposed between the fuel electrode layer of the i-th power generation cell and the oxidant electrode layer of the (i + 1) -th power generation cell. A porous fuel electrode current collector is interposed between the separators, and a porous oxidant electrode current collector is interposed between the oxidant electrode layer and the separator. A fuel supply passage and an oxidant supply passage are provided in each separator. An oxidant supply passage is formed in the first end plate, a fuel supply passage is formed in the second end plate, and a fuel distributor for supplying fuel gas to the fuel supply passage is provided in the vicinity of the fuel cell. An oxidant distributor for supplying an oxidant gas to the oxidant supply passage is provided in the vicinity of the fuel cell, and a pair of electrode terminals are electrically connected to the first end plate and the second end plate, respectively. The introduced fuel gas passes through the fuel supply passage and The oxidant gas that flows radially from the center of the fuel electrode layer to the outer peripheral edge through the anode current collector and simultaneously introduced into the oxidant distributor passes through the oxidant supply passage and the oxidant electrode current collector. Thus, it flows radially from the approximate center of the oxidizer electrode layer toward the outer periphery. As a result, since all of the surface of the power generation cell contributes to power generation, the number of collisions between the fuel gas and the fuel electrode layer and the number of collisions between the oxidant gas and the oxidant gas increase, so that power generation efficiency is improved. Moreover, since each power generation cell is connected in series via the separator etc. which were formed with the electroconductive material, big electric power can be taken out from a pair of electrode terminal. In addition, since the reaction path increases as the outer diameter of the fuel cell of the present invention is increased, the power generation performance is improved.
[0064]
Each oxidant supply passage formed in the separator or the first end plate introduces an oxidant gas from the outer peripheral surface of the separator or the first end plate and faces the oxidant electrode current collector of the separator or the first end plate. If the oxidant gas is discharged from the surface substantially uniformly in a shower shape, the oxidant gas is discharged from the oxidant supply passage in a shower shape substantially uniformly toward the oxidant electrode current collector. The power generation cell can be heated and cooled uniformly. Also, by generating Joule heat during power generation of the fuel cell, when the power generation cell is heated and rises above the set temperature, the oxidant gas having a temperature slightly lower than the set temperature is discharged from the oxidant supply passage. Since the power generation cell can be cooled uniformly, damage due to local heating or cooling of the power generation cell can be prevented.
A plurality of insertion holes are formed in each of the n separators, the single first end plate, and the single second end plate so as not to communicate with either the fuel supply passage or the oxidant supply passage. If the first heater is inserted into the insertion hole, the temperature of the power generation cell can be quickly raised by energizing the first heater when the fuel cell is started, so that the temperature raising time can be shortened. Moreover, since the temperature of the power generation cell is increased uniformly, the temperature difference between the center and the outer periphery of the power generation cell is eliminated and the thermal expansion is performed uniformly, so that the power generation cell can be prevented from being damaged. If the first heater and the temperature sensor are inserted into the plurality of insertion holes, the temperature of the separator or the like can be finely controlled by controlling the first heater based on the detection output of the temperature sensor.
If a plurality of weight reduction holes are formed in each of the n separators, the single first end plate, and the single second end plate so as not to communicate with any of the fuel supply passage and the oxidant supply passage, Since the weight of the separator, the first end plate, and the second end plate can be reduced, the weight of the fuel cell can be reduced.
[0066]
  A fuel preheating tube for supplying fuel gas to the fuel distributor is wound around the outer peripheral surface of the fuel cell, and an oxidant preheating tube for supplying oxidant gas to the oxidant distributor is wound around the outer peripheral surface of the fuel cell. If the exhaust pipe that guides the fuel gas and oxidant gas discharged from the power generation cell to the outside of the inner case is connected to the inner case, the fuel that passes through the fuel preheating pipe The gas is heated by the high temperature exhaust gas discharged from the power generation cell and supplied to the fuel distributor, and the oxidant gas passing through the oxidant preheating pipe is also heated by the high temperature exhaust gas discharged from the power generation cell to be the oxidant distributor. To be supplied. As a result, fuel gas and oxidant gas are supplied to each power generation cell at a temperature suitable for power generation, so that power generation efficiency can be improved..
[0067]
MaSilver plating on at least the inner surface of the inner case,OrSilver plating through nickel base platingBy using the radiant heat generated by the power generation cell during the operation of the fuel cell, the heat retention effect of the power generation cell and the separator can be further enhanced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a fuel cell module according to an embodiment of the present invention.
2 is a cross-sectional view of the fuel cell taken along line AA in FIG.
3 is a cross-sectional view taken along line BB in FIG.
4 is a cross-sectional view taken along the line CC in FIG. 2;
[Explanation of symbols]
10 Fuel cell module
11 Fuel cell
12 Power generation cell
12a Solid electrolyte layer
12b Fuel electrode layer
12c Air electrode layer (oxidant electrode layer)
13 Fuel distributor
14 Distributor for air (Distributor for oxidizing agent)
16 Separator
16a insertion hole
16b, 21b, 22b Slit
17 Current collector for fuel electrode
18 Air electrode current collector (oxidant electrode current collector)
21 First end plate
22 Second end plate
23, 26 Fuel supply passage
24, 27 Air supply passage (oxidant supply passage)
28 Short tube for fuel
29 Short tube for air (short tube for oxidizing agent)
31 First heater
32 Second heater
36 Fuel insulation pipe
37 Fuel Sealing Member
38 Insulating tube for air (insulating tube for oxidizing agent)
39 Air sealing member (oxidant sealing member)
41, 42 electrode terminals
43 Fuel preheating tube
44 Air preheating tube (oxidizer preheating tube)
46 Inner case
47 Insulation
48 Outer case
51 First exhaust pipe
52 Second exhaust pipe
53 Water separator
58 Temperature sensor
59 Flow control valve

Claims (4)

There are (n + 1) power generation cells (12) composed of an electrolyte layer (12a) and a fuel electrode layer (12b) and an oxidant electrode layer (12c) disposed on both surfaces of the electrolyte layer (12a) (n is a positive value). A stacked fuel cell, and
The fuel electrode layer (12b) of the i-th (i = 1, 2,..., N) power generation cell (12) and the oxidation of the (i + 1) th power generation cell (12) adjacent to the fuel electrode layer (12b). A total of n separators (16) each formed in a plate shape with a conductive material are interposed between the electrode layer (12c),
A porous fuel electrode assembly having conductivity between the fuel electrode layer (12b) of the i-th power generation cell (12) and the j-th (j = 1, 2,..., N) separator (16). Electrical body (17) is installed,
A porous oxidant electrode current collector (18) having conductivity is interposed between the oxidant electrode layer (12c) of the (i + 1) th power generation cell (12) and the jth separator (16). Dressed,
A single first end plate (21) formed of a conductive material on the oxidant electrode layer (12c) of the first power generation cell (12) through the oxidant electrode current collector (18). Are stacked,
A single second end plate (22) formed of a conductive material on the fuel electrode layer (12b) of the (n + 1) th power generation cell (12) through a fuel electrode current collector (17). Are stacked,
The n separators (16) introduce fuel gas from the outer peripheral surface of the separator (16) and discharge the fuel gas from the center of the separator (16) toward the fuel electrode current collector (17). And an oxidant supply passage (24) for introducing an oxidant gas from the outer peripheral surface of the separator (16) and discharging it from the surface of the separator (16) facing the oxidant electrode current collector (18). And
An oxidant supply passage (27) through which the single first end plate (21) discharges the oxidant gas from the surface of the first end plate (21) facing the oxidant electrode current collector (18). Have
The single second end plate (22) has a fuel supply passage (26) for discharging the fuel gas from the center of the second end plate (22) toward the anode current collector (17). ,
A fuel distributor (13) for supplying fuel gas to each of the fuel supply passages (23, 26) through a fuel short pipe (28) is provided at a side of the fuel cell (11) with an interval therebetween ,
An oxidant distributor (14) for supplying an oxidant gas to the oxidant supply passages (24, 27) through an oxidant short pipe (29) is provided at a side of the fuel cell (11) with a space therebetween. And
A pair of electrode terminals (41, 42) are electrically connected to the first end plate (21) and the second end plate (22), respectively .
Oxidant electrode current collector of the introducing each oxidant supply passage (24) containing gas formed in the n sheets of the separator (16) from the separator (16) outer peripheral surface a separator (16) (18 ) Is configured to be discharged in the form of a shower from the surface facing the
Surface wherein the single first end plate (21) to form oxidant supply passage (27) is opposed to the oxidant gas to the oxidant electrode current collector of the first end plate (21) (18) A fuel cell module configured to be discharged in a shower form . N separators (16), a single first end plate (21), or a single second so as not to communicate with any of the fuel supply passages (23, 26) and the oxidant supply passages (24, 27). A plurality of insertion holes (16a) are formed in one or more of the end plates (22), and one or both of the first heater (31) and the temperature sensor are formed in the plurality of insertion holes (16a). There inserted claims 1 fuel cell module according. Multiple weight reductions in one or more of n separators, a single first end plate, or a single second end plate so as not to communicate with either the fuel supply passage or the oxidant supply passage fuel cell module according to claim 1, wherein the holes are formed. A fuel preheating pipe (43) for supplying fuel gas to the fuel distributor (13) is wound around the outer peripheral surface of the fuel cell (11),
An oxidant preheating pipe (44) for supplying an oxidant gas to the oxidant distributor (14) is wound around the outer peripheral surface of the fuel cell (11),
The fuel cell (11) is housed in an inner case (46) together with the fuel preheating pipe (43) and the oxidant preheating pipe (44),
An exhaust pipe (51) for guiding the fuel gas and the oxidant gas discharged from the power generation cell (12) to the outside of the inner case (46) is connected to the inner case (46) ,
The fuel cell module according to any one of claims 1 to 3, wherein at least an inner surface of the inner case (46) is silver-plated through silver plating or nickel base plating .

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