JP5294145B2 - Fuel cell - Google Patents

Description

  The present invention relates to an improvement in a fuel cell having a structure in which a plurality of fuel cell units are stacked to form a stack structure and the stack structure is housed in a case.

As a conventional fuel cell, a stack structure formed by stacking a plurality of fuel cell units is accommodated in a case, and a reaction gas is circulated through a preheating cavity provided in a wall portion of the case to radiate the stack structure. Some have preheated the reaction gas in the preheating cavity with heat (see Patent Document 1).
2004-139960

  In general, in a fuel cell, during high load operation where the heat generation amount of the fuel cell unit during power generation is larger than the heat dissipation amount of the stack structure body, a cooling gas is introduced between the fuel cell units of the stack structure body to form a stack structure. The whole body needs to be cooled.

  Here, if the cooling gas is not introduced between the fuel cell units of the stack structure, the temperature of the stack structure becomes too high. In each fuel cell unit, the electrical resistance increases due to metal corrosion, and the single cell (power generation element) There is a problem that it cannot be said that there is no possibility that the power generation output is reduced due to the interface peeling between the electrode and the electrolyte and the strength is deteriorated at the joint between the single cell and the cell plate.

  Moreover, when the cooling gas is directly introduced between the fuel cell units of the stack structure, a difference in temperature distribution inside the stack structure becomes remarkable, and in each fuel cell unit, contact failure due to deformation of the metal material, There has been a problem that it cannot be said that there is no possibility of a decrease in power generation performance due to poor contact or a thermal stress failure due to a difference in thermal expansion coefficient between the single cell and the cell plate.

  The present invention has been made paying attention to the above-described conventional problems, and achieves uniform temperature distribution in the fuel cell unit and the stack structure while favorably adjusting the temperature in the high load operation and the low load operation. An object of the present invention is to provide a fuel cell.

  The fuel cell of the present invention forms a stack structure by stacking a plurality of fuel cell units with a gap therebetween, and the stack structure is accommodated in a case, and either the fuel gas or the oxidant gas is contained in the case. One reaction gas introduction part and a discharge part are arranged to circulate the reaction gas in the case.

The fuel cell is provided with an outer peripheral gas guide member extending from the reaction gas introduction portion along the outer peripheral edge of the stack structure, and between the case inner surface and the outer peripheral gas guide member, the flow rate of the reaction gas on the downstream side. And an outer peripheral gas passage that increases at least one of the flow rates, and a part of the reaction gas introduced from the outer peripheral gas passage is circulated between the outer peripheral gas guiding member and the stack structure and reacted downstream. The inner gas flow path for reducing at least one of the flow velocity and the flow rate of the working gas is formed , and the above structure is used as means for solving the conventional problems.

  According to the fuel cell of the present invention, it is possible to achieve uniform temperature distribution in the fuel cell unit and the stack structure while favorably adjusting the temperature in the high load operation and the low load operation.

13 to 16 are diagrams for explaining the basic configuration of a fuel cell to which the present invention can be applied.
A fuel cell 100 shown in FIGS. 15 and 16 has a structure in which a plurality of fuel cell units U are stacked with a gap therebetween to form a stack structure S, and the stack structure S is accommodated in a case C. ing.

  The illustrated fuel cell unit U is a circular disk type. Therefore, the stack structure S has a substantially columnar shape, and the case C that accommodates the stack structure S has a cylindrical shape.

  As shown in FIG. 13, the fuel cell unit U includes an annular unit cell 1 that is a power generation element, a separator 2 that faces the surface of the unit cell 1 on the fuel electrode side, and a center hole of the unit cell 1. A peripheral member 3 and an outer peripheral member 4 that holds the outer periphery of the single cell 1 are provided.

  The single cell 1 includes a solid electrolyte layer sandwiched between a fuel electrode layer and an air electrode layer, and constitutes a cell plate together with an inner peripheral member 3 attached to a central hole and an outer peripheral member 4 holding an outer peripheral portion. . The unit cell 1 is not particularly limited in configuration, and may be any one of, for example, an electrode support cell, an electrolyte support cell, and a porous metal support cell.

  The fuel cell unit U includes a current collector 5 in the unit between the single cell 1 and the separator 2, and the outer edges of the separator 2 and the outer peripheral member 4 are hermetically bonded to each other. A flat gas chamber having a bag binding structure is formed between the separators 2. In addition, the unit-side current collector 6 interposed between the separator 2 of the adjacent fuel cell unit U is provided on the surface of the unit cell 1 on the air electrode side.

  For the separator 2, the inner peripheral member 3, and the outer peripheral member 4, a material having a thermal expansion rate close to that of the single cell 1 or a material having substantially the same thermal expansion rate is selected. For example, in the case of a fuel electrode-supported cell using nickel and yttria-stabilized zirconia cermet of a solid oxide fuel cell as a fuel electrode, the coefficient of thermal expansion is about 10. A ferrite metal or the like that is about E-6 [1 / K] is preferable. In particular, SUS430, ZMG232 having excellent oxidation resistance and corrosion resistance, or Croffer22APU are more preferable among ferrites. The separator 2 and the outer peripheral member 4 can be joined by welding, brazing, ultrasonic joining, or the like, by processing the outer edges by pressing.

  Further, the separator 2 and the inner peripheral member 3 are provided with a fuel gas introduction hole 7 and a discharge hole 8. As shown in FIG. 14, the introduction hole 7 and the discharge hole 8 form a fuel gas introduction pipe and a discharge pipe continuously in a stack structure S in which a plurality of fuel cell units U are stacked.

  The fuel cell 100 in which the stack structure S is accommodated in the case C introduces the fuel gas into each fuel cell unit U and supplies the fuel gas to the fuel electrode of the single cell 1. An oxidant gas (air) is introduced into the air, and the oxidant gas is supplied to the air electrode of the single cell 1, and electric energy is generated by an electrochemical reaction in the single cell 1.

  Note that the case C may have a gas tight wall portion, and the wall portion may be formed of a heat insulator, or may be provided with another heat insulating container integrally therein.

  Here, the fuel cell 100 shown in FIGS. 15 and 16 is disposed between the case C and the stack structure S between the pair of oxidant gas introduction pipes 11 and 11 and the two introduction pipes 11 and 11. A discharge pipe 12 is provided. The introduction pipe 11 and the discharge pipe 12 are continuous in the stacking direction of the fuel cell unit U. In particular, the pair of introduction pipes 11 and 11 are open in directions opposite to each other.

  The fuel cell 100 includes an outer peripheral gas guide member 13 extending from the introduction pipes 11 and 11 along the outer peripheral portion of the stack structure S. Both outer peripheral gas guiding members 13 form an outer peripheral gas flow path 14 between the inner surface of the case C and an opening region 15 leading to the accommodation space of the stack structure S between the tip portions. .

  The fuel cell 100 introduces a cooling gas from the introduction pipes 11 and 11 at the time of high load operation in which the amount of heat generated from the single cell 1 during power generation is larger than the amount of heat released from the stack structure S, By flowing this cooling gas to the outer peripheral gas flow path 14, the stack structure S is cooled, and at the same time, the introduced cooling gas is preheated and supplied from the opening region 15 to the stack structure S.

  Further, during low load operation in which the calorific value of the single cell 2 is smaller than the heat dissipation amount of the stack structure S, the heated gas is introduced from the introduction pipes 11, 11, and this heated gas is supplied to the outer gas flow path 14. By flowing, the stack structure S is heated, and at the same time, heated gas is supplied to the stack structure S from the opening area 15.

  Since the fuel gas is an off-gas of the reformer and the temperature hardly changes, the oxidant gas (air) introduced into the case is used as a cooling gas or a heating gas to adjust the temperature of the fuel cell 100 as described above. It is preferable to use as.

  As described above, the fuel cell 100 performs heat exchange between the oxidant gas flowing through the outer peripheral gas flow path 14 and the stack structure S via the outer peripheral gas guiding member 13, so that each fuel cell unit U and The temperature distribution in the stack structure S can be made uniform.

  By the way, in the fuel cell 100 described above, the use of the outer peripheral gas guide member 13 significantly improves the temperature distribution compared to a structure in which the oxidant gas flows in one direction in the case. There is room for improvement in further uniforming the distribution.

  That is, in the fuel cell 100 described above, the heat exchange amount between the oxidant gas and the stack structure S is large upstream of the outer peripheral gas flow path 14, and the heat exchange amount is small downstream of the outer peripheral gas flow path 14. The difference in the amount of heat exchange between the upstream side and the downstream side is large. Therefore, the present invention realizes further uniform temperature distribution by changing the flow rate and flow rate of the oxidant gas mainly used as the cooling gas.

  FIG. 1 is a diagram illustrating an embodiment of a fuel cell according to the present invention. The fuel cell of the present invention has a basic configuration equivalent to that of the fuel cell 100 described with reference to FIGS. Therefore, the same components as those of the basic configuration are denoted by the same reference numerals and detailed description thereof is omitted.

  A fuel cell FC1 shown in FIG. 1 is formed by stacking a plurality of fuel cell units U with a gap therebetween to form a stack structure S, and housing the stack structure S in a case C. The fuel cell FC1 has a structure in which a reaction gas introduction part and a discharge part of either one of the fuel gas and the oxidant gas are arranged in the case C, and the reaction gas is circulated in the case C. Yes. In this embodiment, a pair of introduction pipes 11 and 11 is provided as an introduction part, and a discharge pipe 12 disposed between the introduction pipes 11 and 11 is provided as a discharge part, and an oxidizing agent which is one reaction gas. Gas is introduced and discharged.

  Further, the fuel cell FC1 is provided with a pair of outer peripheral gas guide members 13, 13 extending from the introduction portions 11, 11 along the outer peripheral edge portion of the stack structure S, and between the inner surface of the case C and the outer peripheral gas guide member 13. The outer peripheral gas flow paths 14 and 14 for increasing at least one of the flow rate (molar flow rate) and the flow rate (molar flow rate) of the reaction gas are formed on the downstream side.

  More specifically, in the fuel cell FC1, the outer peripheral gas flow paths 14, 14 are disconnected from the upstream side toward the downstream side by disposing the stack structure S eccentrically with respect to the center of the case C. The area gradually decreases. That is, the outer peripheral gas flow path 14 of this embodiment increases the flow rate (molar flow rate) of the oxidant gas on the downstream side.

  When the fuel cell FC1 is operated at a high load, in the stack structure S, the temperature on the discharge side is higher than the temperature of the oxidant gas on the introduction side. Accordingly, the exhaust side portion of the stack structure S is cooled by the oxidant gas flowing in the outer peripheral gas flow paths 14 and 14, and at the same time, the oxidant gas is preheated and introduced into the stack structure S, whereby each fuel. The temperature distribution of the battery unit U and the stack structure S can be made uniform.

  On the other hand, during low load operation, the temperature of the oxidant gas on the introduction side is lower than the temperature on the discharge side. Therefore, by introducing the heating gas, the stack structure S can be heated via the outer peripheral gas guiding members 13 and 13, and the temperature distribution of each fuel cell unit U and the stack structure S can be made uniform.

  Moreover, the fuel cell FC1 described above has a particularly low flow rate by gradually decreasing the cross-sectional area of each of the outer peripheral gas flow paths 14, 14 from the upstream side toward the downstream side and increasing the flow rate of the oxidant gas on the downstream side. On the downstream side where the gas flow rate is large, the boundary film heat transfer coefficient between the gas flowing through the peripheral gas flow path 14 and the solid forming the peripheral gas guide member 13 is small.

  Thereby, the difference between the heat exchange amount on the upstream side of the outer peripheral gas flow path 14 (heat exchange amount between the oxidant gas and the stack structure S) and the heat exchange amount on the downstream side is reduced. As a result, the fuel cell FC1 can achieve further uniform temperature distribution in the fuel cell unit U and the stack structure S while performing temperature adjustment well. Along with the uniform temperature distribution, it is possible to prevent problems such as thermal stress destruction of joint portions of each component and a decrease in power generation performance due to deformation of metal materials.

  In the fuel cell FC1 of this embodiment, the fuel cell unit U has a disk shape, and the stack structure S in which the fuel cell units U are stacked has a cylindrical shape. The outer peripheral gas guiding members 13 and 13 form an arc shape along the outer peripheral edge of the stack structure S, and have an opening area 15 between the outer peripheral gas guiding members 13 and 13.

Furthermore, the fuel cell FC1 in this embodiment, on a circle circumference of the fuel cell unit U, as well as arranging the opening area 15 of the discharge pipe 12 and the outer gas guiding members 13 of the oxidizing gas to 180 degrees different positions, the discharge pipe Introductory pipes 11 and 11 and outer gas guide members 13 and 13 are arranged on both sides of 12, respectively. Thus , the oxidant gas introduction pipes 11 and 11, the exhaust pipe 12, the outer gas guide members 13 and 13, the outer circumference , with the center line of the circle of the fuel cell unit U passing through the exhaust pipe 12 and the opening region 15 as the symmetry axis. The gas flow paths 14, 14 and the opening area 15 are arranged in line symmetry.

  Further, in the fuel cell FC1 of this embodiment, the fuel cell units U are connected to each other at the central portion to form the stack structure S, and the stack structure S is used for the other reaction along the center line. A fuel gas introduction part and a gas exhaust part are provided, and the fuel gas is circulated in each fuel cell unit U.

  In the fuel cell FC1 of the present invention, by setting the shape and arrangement of each component as described above, the oxidant gas is more uniformly distributed, and the temperature distribution of the fuel cell unit U and the stack structure S is further uniform. Can contribute. Further, in the stack structure S, only the central portion is pressurized in the assembly, and the outer peripheral portions of the fuel cell units U are not restrained at all, so that thermal expansion and thermal stress generated during operation can be suppressed. .

  FIG. 2 is a diagram for explaining another embodiment of the fuel cell of the present invention. The same components as those in the previous basic configuration and the embodiment are assigned the same reference numerals, and detailed description thereof is omitted.

  The illustrated fuel cell FC2 increases the flow rate of the oxidant gas on the downstream side of the outer gas path 14 in the previous embodiment, whereas the flow rate of the oxidant gas on the downstream side of the outer gas path 14 (Molar flow rate) is increased.

  More specifically, the fuel cell FC2 includes an introduction pipe 11 that is a plurality of reaction gas introduction sections while the outer peripheral gas flow path 14 extends from the upstream side to the downstream side. In the illustrated example, six introduction pipes 11 are arranged at equal intervals in each peripheral gas flow path 14. And since the outer periphery gas flow path 14 is obstruct | occluded in the upstream, when oxidant gas is introduce | transduced from each inlet tube 11, the flow volume of oxidant gas will increase as it goes downstream.

  The fuel cell FC2 described above increases the flow rate of the oxidant gas on the downstream side of the outer peripheral gas flow path 14, so that the gas that flows through the outer peripheral gas flow path 14 and the solid that forms the outer peripheral gas guiding member 13 particularly on the downstream side. And the difference between the heat exchange amount on the upstream side and the heat exchange amount on the downstream side becomes small. As a result, the fuel cell FC2 can achieve further uniform temperature distribution in the fuel cell unit U and the stack structure S while performing temperature adjustment well.

  FIG. 3 is a view for explaining still another embodiment of the fuel cell of the present invention. The same components as those in the previous basic configuration and the embodiment are assigned the same reference numerals, and detailed description thereof is omitted.

  In the illustrated fuel cell FC3, the discharge pipe 12 and the introduction pipe 11 are arranged inside and outside, and a plurality of flow dividing plates 16 are arranged at an appropriate angle in the outer peripheral gas flow path 14 so as to be downstream of each flow dividing plate 16. The flow rate of the oxidant gas is increased. In this fuel cell FC3 as well, the temperature distribution in the fuel cell unit U and the stack structure S can be made more uniform while the temperature is adjusted well as in the previous embodiment.

  FIG. 4 is a view for explaining still another embodiment of the fuel cell of the present invention. The same components as those in the previous basic configuration and the embodiment are assigned the same reference numerals, and detailed description thereof is omitted.

  The illustrated fuel cell FC4 includes a plurality of oxidant gas introduction portions 21 while the outer peripheral gas flow path 14 extends from the upstream side to the downstream side. In this embodiment, three introduction portions 21 are integrated with the wall portion of the case C at a predetermined interval. In the fuel cell FC4 as well, as in the embodiment shown in FIG. 2, the temperature distribution in the fuel cell unit U and the stack structure S can be made more uniform while the temperature is adjusted well.

  FIG. 5 is a diagram illustrating still another embodiment of the fuel cell of the present invention. The same components as those in the previous basic configuration and the embodiment are assigned the same reference numerals, and detailed description thereof is omitted.

  The fuel cell FC5 shown in FIG. 5A is provided with an outer peripheral gas guiding member 13 extending from the oxidant gas introduction pipe 11 along the outer peripheral edge of the stack structure S, and the inner surface of the case C and the outer peripheral gas guiding member 13 are provided. The outer peripheral gas flow path 14 is formed between the two. The outer peripheral gas flow path 14 of this embodiment has substantially the same cross-sectional area from the upstream side toward the downstream side.

  In the fuel cell FC5, a part of the oxidant gas introduced from the peripheral gas flow path 14 is circulated between the peripheral gas guiding member 13 and the stack structure S, and the flow rate (moles) of the oxidant gas on the downstream side. An inner peripheral gas flow path 17 that reduces at least one of a flow rate and a flow rate (molar flow rate) is formed.

  More specifically, in the fuel cell FC5, the fuel cell unit U is provided with a pair of inner peripheral gas guiding members 18 and 18 along the outer periphery thereof. In particular, as shown in FIG. Inner peripheral gas guide members 18, 18 are provided along the outer peripheral portion of the outer current collector 6, and each inner peripheral gas flow path is provided between each outer peripheral gas guide member 13 and each inner peripheral gas guide member 18. 17 and 17 are formed. The pair of inner peripheral gas guide members 18, 18 are separated from each other on the opening region 15 side and the discharge pipe 12 side.

  In addition, the fuel cell FC5 of this embodiment includes an insulating layer 19 having electrical insulation and thermal conductivity between the stack structure S and the outer gas guide member 13.

  The fuel cell FC5 has a configuration in which the inner peripheral gas flow path 17 gradually increases in cross-sectional area from the upstream side to the downstream side. That is, the inner peripheral gas flow path 17 increases the cross-sectional area on the downstream side, thereby decreasing the flow rate (molar flow rate) of the oxidant gas on the downstream side.

  The fuel cell FC5 described above has a particularly high flow rate by gradually increasing the cross-sectional area of each inner peripheral gas flow path 17, 17 from the upstream side toward the downstream side and decreasing the flow rate of the oxidant gas on the downstream side. On the small downstream side, the boundary film heat transfer coefficient between the gas flowing through the inner peripheral gas flow path 17 and the solid forming the inner peripheral gas guiding member 18 increases.

  Thereby, the difference between the heat exchange amount on the upstream side of the inner peripheral gas flow path 17 (heat exchange amount between the oxidant gas and the stack structure S) and the heat exchange amount on the downstream side is reduced. As a result, the fuel cell FC5 can achieve further uniform temperature distribution in the fuel cell unit U and the stack structure S while performing temperature adjustment well.

  FIG. 6 is a view for explaining still another embodiment of the fuel cell of the present invention. The same components as those in the previous basic configuration and the embodiment are assigned the same reference numerals, and detailed description thereof is omitted.

  The fuel cell FC6 shown in FIG. 6 (a) is provided with the inner peripheral gas guiding members 18 and 18 on the outer peripheral portion of the outer current collector 6 in the previous embodiment, whereas in FIG. 6 (b). As shown, inner peripheral gas guiding members 18 are provided along the outermost peripheral portion of each fuel cell unit U, that is, along the outer peripheral portion of the stack structure S. The inner gas passages 17 and 17 are formed between the outer gas guide members 13 and the inner gas guide members 18.

  In addition, an insulating layer 19 having electrical insulation and thermal conductivity is provided on the inner circumferential surface of the inner circumferential gas guiding member 18, and between this insulating layer 19 and the unit external current collector 6. Also, an insulating member 20 is interposed.

  In the fuel cell FC6, the inner peripheral gas flow path 17 has a form in which the cross-sectional area is gradually increased from the upstream side to the downstream side, whereby the flow rate (molar flow rate) of the oxidant gas on the downstream side. Decrease.

  Even in the fuel cell FC6, as in the previous embodiment, the temperature distribution in the fuel cell unit U and the stack structure S can be made more uniform while the temperature is adjusted well.

  Here, as in the embodiment shown in FIG. 5 and FIG. 6, in the configuration employing the inner peripheral gas guide member 18, the inner peripheral gas guide member 18 includes each fuel cell unit as shown in FIG. It may be provided for each U, or may be a continuous plate member along the outer periphery of the stack structure S as shown in FIG.

  Moreover, in the structure which provides the inner periphery gas induction | guidance | derivation member 18 in the outer peripheral part of the unit outer current collector 6, for example, when the unit outer current collector 6 is a porous metal, a metal glass as a filler is provided on the outer periphery of the current collector. The inner circumference gas induction member 18 may be provided by using Ag brazing material, glass paste, ceramic adhesive, etc., and the inner circumference gas induction is performed on the outer circumference of the current collector by spot welding via a metal ring. The member 18 may be joined.

  Further, when the unit outer current collector 6 has a structure in which a large number of leaf spring-like projecting pieces are cut and formed on a single plate, the outer peripheral portion of the plate is bent by a press to guide the inner peripheral gas. It can be used as a member. The inner peripheral gas guide member 18 is not limited to these configurations.

  FIG. 7 is a diagram illustrating still another embodiment of the fuel cell of the present invention. The same components as those in the previous basic configuration and the embodiment are assigned the same reference numerals, and detailed description thereof is omitted.

  In the fuel cell FC7 shown in FIG. 7A, the inner peripheral gas guide member 18 has a large number of vent holes 18a, and the vent holes 18a extend from the upstream side to the downstream side of the inner peripheral gas flow path 17. The distribution density is gradually increased. Note that the size of the vent hole 18a may be gradually increased from the upstream side toward the downstream side.

  In this case, the insulating layer 19 shown in FIG. 7B is made of a material having gas permeability. In addition, as shown in FIG. 7C, an insulating member 20 having gas permeability may be interposed between the inner peripheral gas guiding member 18 and the unit outer current collector 6.

  In the fuel cell FC7 described above, the flow rate (molar flow rate) of the oxidant gas is decreased on the downstream side by causing the oxidant gas to flow from the vent hole 18a to the outside of the flow channel on the downstream side in the inner gas channel 17. As a result, on the downstream side, the boundary film heat transfer coefficient between the gas flowing through the inner peripheral gas flow path 17 and the solid forming the inner peripheral gas guiding member 18 is increased, and the upstream heat exchange amount and the downstream heat exchange are increased. The difference from the amount is reduced. As a result, the temperature distribution in the fuel cell unit U and the stack structure S can be further uniformized while the temperature is adjusted favorably.

  Further, the fuel cell FC7 causes the oxidant gas to flow from the vent hole 18a to the outside of the flow path on the downstream side of the inner peripheral gas flow path 17 as described above, and in particular due to the shortage of the oxidant gas on the discharge side of the stack structure S. A decrease in power generation performance can also be prevented.

  FIG. 8 is a diagram illustrating still another embodiment of the fuel cell of the present invention. The same components as those in the previous basic configuration and the embodiment are assigned the same reference numerals, and detailed description thereof is omitted.

  A fuel cell FC7 shown in FIG. 8A is provided with an inner peripheral gas guiding member 18 for each fuel cell unit U, and an inner peripheral gas flow between the inner peripheral gas guiding member 18 and the outer peripheral gas guiding member 13 is provided. A path 17 is formed.

  At this time, the inner peripheral gas guide member 18 is joined to the outer peripheral portion of the unit outer current collector 6 on the upstream side of the inner peripheral gas flow path 17 as shown in FIG. As shown in FIG. The inner peripheral gas guide member 18 has a large number of vent holes 18a in the downstream portion, and gradually increases the distribution density (or size) of the vent holes 18a toward the downstream side. In this case, an insulating coating 22 is applied to a portion (a part of the cell plate) facing the inner peripheral gas flow path 17 of the fuel cell unit U.

  Even in the fuel cell FC8, as in the previous embodiment, by reducing the flow rate of the oxidant gas on the downstream side of the inner peripheral gas flow path 17, the film heat transfer coefficient on the downstream side is increased. At the same time, the difference between the heat exchange amount on the upstream side and the heat exchange amount on the downstream side becomes small. As a result, the temperature distribution in the fuel cell unit U and the stack structure S is further uniformized while the temperature is adjusted well. In addition, it is possible to prevent a decrease in power generation performance due to a shortage of oxidant gas on the discharge side of the stack structure S.

  FIG. 9 is a diagram illustrating still another embodiment of the fuel cell of the present invention. The same components as those in the previous basic configuration and the embodiment are assigned the same reference numerals, and detailed description thereof is omitted.

  The illustrated fuel cell FC9 is configured without the inner peripheral gas guiding member of the previous embodiment, and an inner peripheral gas flow path 17 is formed between the outer peripheral gas guiding member 13 and the external current collector (FIG. 7b). The inner peripheral gas channel 17 includes a rectifying member that deflects the oxidant gas to the outside of the channel on the downstream side. That is, the flow rate of the oxidant gas on the downstream side is reduced by providing a rectifying member on the downstream side of the inner peripheral gas flow path 17. In the fuel cell FC9 of this embodiment, the rectifying member is one rectifying plate 23 arranged in the inner peripheral gas flow path 17.

  Even in the fuel cell FC9 described above, as in the previous embodiment, by reducing the flow rate of the oxidant gas on the downstream side of the inner peripheral gas passage 17, the boundary film heat transfer coefficient on the downstream side is increased. At the same time, the difference between the heat exchange amount on the upstream side and the heat exchange amount on the downstream side becomes small. As a result, the temperature distribution in the fuel cell unit U and the stack structure S is further uniformized while the temperature is adjusted well. In addition, it is possible to prevent a decrease in power generation performance due to a shortage of oxidant gas on the discharge side of the stack structure S.

  FIG. 10 is a diagram illustrating still another embodiment of the fuel cell of the present invention. The same components as those in the previous basic configuration and the embodiment are assigned the same reference numerals, and detailed description thereof is omitted.

  In the illustrated fuel cell FC <b> 10, the rectifying member is a plurality (two) of rectifying plates 23 arranged in the inner peripheral gas flow path 17. The number of rectifying plates 23 is not particularly limited, and at least one rectifying plate is sufficient.

  Even in the fuel cell FC10, as in the previous embodiment, by reducing the flow rate of the oxidant gas on the downstream side of the inner peripheral gas flow path 17, the film heat transfer coefficient on the downstream side is increased. At the same time, the difference between the heat exchange amount on the upstream side and the heat exchange amount on the downstream side becomes small. As a result, the temperature distribution in the fuel cell unit U and the stack structure S is further uniformized while the temperature is adjusted well. In addition, it is possible to prevent a decrease in power generation performance due to a shortage of oxidant gas on the discharge side of the stack structure S.

  FIG. 11 is a diagram illustrating still another embodiment of the fuel cell of the present invention. The same components as those in the previous basic configuration and the embodiment are assigned the same reference numerals, and detailed description thereof is omitted.

  The illustrated fuel cell FC11 forms an inner peripheral gas flow path 17 (see FIG. 7b) between the outer peripheral gas guiding member 13 and the external current collector, and the inner peripheral gas flow path 17 is oxidized on the downstream side thereof. A rectifying member for deflecting the agent gas to the outside of the flow path is provided. That is, the flow rate of the oxidant gas on the downstream side is reduced by providing a rectifying member on the downstream side of the inner peripheral gas flow path 17.

  In the fuel cell FC11 of this embodiment, the rectifying member is a porous body 24 disposed in the inner peripheral gas flow path 17, and includes an upstream portion, a midstream portion, and a downstream portion of the inner peripheral gas flow passage 17. The porosity is gradually reduced.

  Here, the material of the porous body 24 is not particularly limited, but (1) castable refractories, (2) refractory foam cements such as Portland cement, alumina cement, phosphate cement and silicate cement; 3 refractory mortar, (4) gypsum, (5) ceramic adhesive, (6) amorphous material such as foam glass, (7) felt mainly composed of at least one of glass fiber, ceramic fiber and metal fiber, 8) Woven fabrics, (9) knitted fabrics, (10) composite materials containing these, (11) metal foils, and (12) inorganic mats that expand when heated are used.

  Even in the fuel cell FC11, as in the previous embodiment, by reducing the flow rate of the oxidant gas on the downstream side of the inner peripheral gas flow path 17, the boundary film heat transfer coefficient on the downstream side is increased. At the same time, the difference between the heat exchange amount on the upstream side and the heat exchange amount on the downstream side becomes small. As a result, the temperature distribution in the fuel cell unit U and the stack structure S is further uniformized while the temperature is adjusted well. In addition, it is possible to prevent a decrease in power generation performance due to a shortage of oxidant gas on the discharge side of the stack structure S.

  FIG. 12 is a diagram illustrating still another embodiment of the fuel cell of the present invention. The same components as those in the previous basic configuration and the embodiment are assigned the same reference numerals, and detailed description thereof is omitted.

  The illustrated fuel cell FC12 forms an inner peripheral gas flow path 17 (see FIG. 7b) between the outer peripheral gas guiding member 13 and the external current collector, and the inner peripheral gas flow path 17 is oxidized on the downstream side thereof. A rectifying member for deflecting the agent gas to the outside of the flow path is provided. That is, the flow rate of the oxidant gas on the downstream side is reduced by providing a rectifying member on the downstream side of the inner peripheral gas flow path 17.

  In the fuel cell FC12 of this embodiment, the rectifying member is the filler 25 filled in the inner peripheral gas flow path 17, and the amount of the filler 25 is gradually increased toward the downstream side. ing.

  Even in the fuel cell FC12, as in the previous embodiment, by reducing the flow rate of the oxidant gas on the downstream side of the inner peripheral gas flow path 17, the film heat transfer coefficient on the downstream side is increased. At the same time, the difference between the heat exchange amount on the upstream side and the heat exchange amount on the downstream side becomes small. As a result, the temperature distribution in the fuel cell unit U and the stack structure S is further uniformized while the temperature is adjusted well. In addition, it is possible to prevent a decrease in power generation performance due to a shortage of oxidant gas on the discharge side of the stack structure S.

  The configuration of the fuel cell of the present invention is not limited to the above-described embodiments. For example, the outer gas guide member, the outer gas channel, the inner gas guide member, the inner gas channel, and the rectifying member are used. The details of the configuration can be changed, or these configurations can be combined other than the above embodiments.

  Further, in each of the embodiments described above, the oxidant gas (air) that is one reaction gas is circulated in the case, and the fuel gas that is the other reaction gas is circulated in the fuel cell unit. However, depending on the configuration of the fuel cell unit, the flow area of the oxidant gas and the fuel gas may be reversed.

  Further, in the present invention, the outer peripheral gas passage increases at least one of the flow velocity and flow rate of the reaction gas on the downstream side, and the inner peripheral gas passage is one of the reaction gases introduced from the outer peripheral gas passage. The part is circulated and at least one of the flow rate and flow rate of the reaction gas is reduced downstream. In each of the examples, the one provided with either one of the outer peripheral gas flow path and the inner peripheral gas flow path having the above functions is exemplified. However, a configuration including both gas flow paths having the respective functions may be used. In addition, regarding the increase / decrease of the flow rate, it can be configured to change continuously or stepwise.

It is a horizontal sectional view explaining one example of a fuel cell of the present invention. It is the horizontal sectional view (a) and perspective explanatory drawing (b) explaining other examples of the fuel cell of the present invention. It is a horizontal sectional view explaining further another example of the fuel cell of the present invention. It is a horizontal sectional view explaining further another example of the fuel cell of the present invention. It is the horizontal sectional view (a) explaining the other Example of the fuel cell of this invention, and the vertical sectional view (b) of the principal part. It is the horizontal sectional view (a) explaining the other Example of the fuel cell of this invention, and the vertical sectional view (b) of the principal part. It is the horizontal sectional view (a) explaining the other Example of the fuel cell of this invention, and the vertical sectional view (b) (c) of the principal part. It is the horizontal sectional view (a) explaining the other Example of the fuel cell of this invention, and the vertical sectional view (b) (c) of the principal part. It is a horizontal sectional view explaining further another example of the fuel cell of the present invention. It is a horizontal sectional view explaining further another example of the fuel cell of the present invention. It is a horizontal sectional view explaining further another example of the fuel cell of the present invention. It is a horizontal sectional view explaining further another example of the fuel cell of the present invention. 1 is an exploded perspective view illustrating a fuel cell unit in a basic configuration of a fuel cell to which the present invention is applicable. 1 is a perspective view illustrating a stack structure in a basic configuration of a fuel cell to which the present invention is applicable. 1 is an explanatory perspective view showing a basic configuration of a fuel cell to which the present invention is applicable. 1 is a horizontal sectional view showing a basic configuration of a fuel cell to which the present invention is applicable.

Explanation of symbols

C Case FC1 to FC12 Fuel cell S Stack structure U Fuel cell unit 1 Single cell 2 Separator 3 Inner peripheral member 4 Outer peripheral member 5 In-unit current collector 6 Outer unit current collector 7 Introduction hole (fuel gas introduction hole)
8 Discharge hole (fuel gas introduction hole)
11 Introduction pipe (oxidizer gas introduction part)
12 Discharge pipe (oxidant gas discharge part)
DESCRIPTION OF SYMBOLS 13 Peripheral gas guide member 14 Peripheral gas flow path 15 Opening area 16 Diverging plate 17 Inner peripheral gas flow path 18 Inner peripheral gas guide member 18a Ventilation hole 19 Insulating layer 20 Insulating member 21 Introduction part (oxidant gas introduction part)
22 Insulating coating 23 Rectifier plate (rectifier member)
24 Porous body (rectifying member)
25 Filler (rectifying member)

Claims (16)

A plurality of fuel cell units are stacked with a gap therebetween to form a stack structure, and the stack structure is accommodated in a case, and either one of the fuel gas and the oxidizing gas is introduced into the case A fuel cell having a structure in which a reaction gas is circulated in the case by arranging a discharge part and a discharge part,
An outer peripheral gas guide member is provided along the outer peripheral edge of the stack structure from the reaction gas introduction part,
Between the inner surface of the case and the outer peripheral gas guiding member, an outer peripheral gas flow path for increasing at least one of the flow velocity and the flow rate of the reaction gas is formed on the downstream side ,
An inner peripheral gas flow that causes a part of the reaction gas introduced from the outer peripheral gas flow path to flow between the outer peripheral gas guide member and the stack structure and reduces at least one of the flow velocity and flow rate of the reaction gas downstream. A fuel cell characterized by forming a path . A plurality of fuel cell units are stacked with a gap therebetween to form a stack structure, and the stack structure is accommodated in a case, and either one of the fuel gas and the oxidizing gas is introduced into the case A fuel cell having a structure in which a reaction gas is circulated in the case by arranging a discharge part and a discharge part,
An outer peripheral gas guide member is provided along the outer peripheral edge of the stack structure from the reaction gas introduction part,
While forming an outer peripheral gas flow path between the case inner surface and the outer peripheral gas guiding member,
An inner peripheral gas flow that causes a part of the reaction gas introduced from the outer peripheral gas flow path to flow between the outer peripheral gas guide member and the stack structure and reduces at least one of the flow velocity and flow rate of the reaction gas downstream. A fuel cell characterized by forming a path.   The fuel cell unit has a disk shape, the stack structure has a cylindrical shape, and the outer peripheral gas guiding member has an arc shape along the outer peripheral edge of the stack structure and has an opening region in part. The fuel cell according to claim 1 or 2. On a circle circumference of the fuel cell unit, the opening area of the discharge portion and the outer peripheral gas guiding members of the reactant gas as well as disposed 180 degrees from the position, the inlet portion and the outer circumferential gas guiding members respectively arranged on both sides of the discharge portion, The fuel gas unit circle passing through the discharge part and the opening region is arranged symmetrically about the center line of the circle of the fuel cell unit, and the reaction gas introduction part, the discharge part, the outer gas guide member and the opening region are arranged in line symmetry. 3. The fuel cell according to 3.   The fuel according to any one of claims 1 to 4, wherein an insulating layer having electrical insulation and thermal conductivity is provided between the stack structure and the peripheral gas guiding member. battery.   Each fuel cell unit is connected to each other at the central portion to form a stack structure, and the stack structure includes the other reaction gas introduction part and the discharge part along the center line. The fuel cell according to any one of claims 3 to 5, wherein the other reaction gas is circulated inside.   The fuel cell according to any one of claims 1 to 3, wherein the outer peripheral gas flow path has a form in which a cross-sectional area is decreased on the downstream side.   7. The fuel cell according to claim 1, wherein the outer peripheral gas flow path is provided with a plurality of reaction gas introduction portions between the upstream side and the downstream side.   The fuel cell unit includes an inner peripheral gas guide member along an outer periphery thereof, and an inner peripheral gas flow path is formed between the outer peripheral gas guide member and the inner peripheral gas guide member. The fuel cell according to any one of 1 to 6.   The fuel cell unit includes an external current collector interposed between adjacent fuel cell units in the stack structure, and an inner peripheral gas flow path is formed between the outer peripheral gas guiding member and the external current collector. The fuel cell according to claim 1, wherein the fuel cell is formed.   The fuel cell according to claim 9 or 10, wherein the inner peripheral gas flow path has a form in which a cross-sectional area is increased on the downstream side.   The inner peripheral gas guide member has a large number of vent holes, and the distribution density of the vent holes is increased from the upstream side to the downstream side of the inner peripheral gas flow path. Fuel cell.   11. The fuel cell according to claim 9, wherein the inner peripheral gas channel includes a rectifying member that deflects the reaction gas to the outside of the channel on the downstream side thereof.   14. The fuel cell according to claim 13, wherein the rectifying member is at least one rectifying plate disposed in the inner peripheral gas flow path.   The rectifying member is a porous body disposed in the inner peripheral gas flow path, and the porosity decreases from the upstream side to the downstream side of the inner peripheral gas flow path. The fuel cell as described.   The fuel cell according to claim 13, wherein the rectifying member is a filler filled in the inner peripheral gas flow path.

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