JP2010238440A - Fuel battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel battery module in which temperature of a fuel battery cell stack is optimized and the fuel battery module can be downsized. <P>SOLUTION: The fuel battery module has a fuel battery cell stack 6 which has a power generation cell 12 and a separator 15 alternately laminated and causes power generation reaction by supplying a reaction gas to the power generation cell 12 arranged inside a box type can 4 which is constituted of an inner can 1 and an outer can 3 covering the inner can 1 through a heat insulating material 2, and a steam generator 8 to generate steam by introducing water. Water piping 5 which supplies water to the steam generator 8 and absorbs heat of the heat insulating material 2 is arranged between the inner can 1 and the outer can 3 and inside the heat insulating material 2 along the face of the can 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel cell module in which a fuel cell stack in which a plurality of single cells made of power generation cells and separators are arranged in a can body, and in particular, without increasing the size of the fuel cell module. The present invention relates to a fuel cell module capable of maintaining an optimum operating temperature.

  This fuel cell module is constructed by alternately laminating a plurality of power generation cells and separators in which a fuel electrode layer and an air electrode layer are arranged on both sides of a solid electrolyte layer inside a box-shaped can body provided with a heat insulating material. The fuel cell stack thus formed, a reformer that generates fuel gas by a reforming reaction, a steam generator that generates steam, and the like are arranged.

  When the fuel cell module configured as described above is in operation, first, water is supplied to the water vapor generator from the outside of the can body. Then, the water vapor generator absorbs the exhaust heat of the fuel cell stack to generate water vapor. Then, the steam is introduced into the reformer.

  Next, when hydrocarbon gas is introduced into the reformer from the outside of the can body and water vapor is introduced from the water vapor generator, the reformer uses the exhaust heat of the fuel cell stack as a heating source. As a result, a reforming reaction is generated by the hydrocarbon reforming catalyst, and hydrogen as a fuel gas is generated. Then, the hydrogen is introduced into the fuel electrode layer of the fuel cell stack.

  On the other hand, air, which is an oxidant gas, is introduced into the air electrode layer of the fuel cell stack from the outside of the can body.

  As described above, by introducing hydrogen and air into the fuel electrode layer and the air electrode layer, a power generation reaction occurs in the fuel cell stack.

  At this time, since the heat insulating material is provided in the can body, the heat insulating material suppresses heat conduction between the heat inside the can body and the outside of the fuel cell module. As a result, the fuel cell stack is maintained in a high temperature atmosphere of 600 ° C. to 800 ° C., which is a temperature at which power can be generated, and the temperature in the can body of 500 ° C. to 600 ° C.

  And although this heat insulating material is made of a material having low heat conductivity, it cannot completely block heat conduction and slightly absorbs the heat in the can, so that the temperature is 50 It is about ℃-600 ℃.

  By the way, many high-power type fuel cell modules are currently developed in which a plurality of fuel cell stacks are arranged in the can.

  This high power fuel cell module increases the amount of heat exhausted as the number of fuel cell stacks increases, and the amount of heat in the can increases. As a result, the heat insulating material cannot sufficiently insulate the heat inside the can and the outside of the fuel cell module. For this reason, it is necessary to increase the thickness of the heat insulating material, and as a result, there is a problem that the fuel cell module is increased in size.

  Therefore, in order to solve the above problems, in Patent Document 1 below, the temperature of the fuel cell stack itself is optimized by significantly increasing the flow rate of air supplied to the fuel cell stack, and the fuel cell module. The one that optimizes the temperature is known.

JP 2008-226704 A

  However, in the invention of Patent Document 1, in order to increase the air flow rate, it is necessary to increase the size of auxiliary equipment such as a blower and a motor, which leads to an increase in the size of the fuel cell module. there were.

  The present invention has been made to solve the problems of the prior art, and provides a fuel cell module capable of optimizing the temperature of the fuel cell stack and miniaturizing the fuel cell module. .

  In order to solve the above-mentioned problem, the present invention according to claim 1 includes an inner can body and a box-shaped can body configured by an outer can body covering the inner can body with a heat insulating material. In addition, the fuel cell stack is configured by alternately stacking power generation cells and separators, and a fuel cell stack that generates a power generation reaction by supplying a reaction gas to the power generation cell, and generates water vapor by introducing water. In the fuel cell module provided with a container, the water is supplied to the water vapor generator between the inner can body and the outer can body, along the surface of the can body, inside the heat insulating material. And a water pipe that absorbs the heat of the heat insulating material is provided.

  Moreover, the present invention described in claim 2 is characterized in that the water pipe is arranged along at least the entire side surface of the can body inside the heat insulating material.

  The present invention according to claim 3 is characterized in that an exhaust pipe for exhausting the exhaust gas generated by the power generation reaction is arranged in the can body, and the steam generator is provided in the exhaust pipe. Is.

The fuel cell module according to claim 4 has an output per volume of the outer can body of 5000 W / cm ³ or more and an output per surface area of the outer can body of 1000 W / cm ² or more. It is characterized by this.

  According to this invention of Claims 1-4, it is between the said inner can body and an outer can body, Comprising: The said water is made inside the said heat insulating material so that the surface of the said can body may be met. Since the water pipe that supplies the water vapor generator and absorbs the heat of the heat insulating material is arranged, the water pipe can absorb the heat of the heat insulating material and reduce the temperature of the heat insulating material. It becomes. Thereby, even if the thickness of the heat insulating material is made thinner than the thickness of the conventional heat insulating material, it becomes possible to sufficiently insulate the heat in the can body, so that the can body can be downsized, As a result, the fuel cell module can be reduced in size.

  Furthermore, even in a high-power fuel cell module that tends to be overheated, the heat inside the can is absorbed by the heat-insulating material whose temperature has decreased, so that the temperature inside the can is reduced to a predetermined temperature atmosphere. It becomes possible to hold.

  Moreover, since the said water piping is surrounded by the heat insulating material, it does not absorb the heat | fever in a can directly, but absorbs only the heat of the heat insulating material distribute | arranged around the water piping. And since the water supplied to the water pipe is constantly flowing at a predetermined water pressure and flow rate, even if the temperature of the heat insulating material is higher than the temperature at which water vaporizes (about 50 ° C. to 600 ° C.), All are not vaporized, part is vaporized, and the remaining part is in a gas-liquid state that maintains the liquid state. As a result, it is not necessary for the water vapor generator to vaporize all the water, and it is sufficient to vaporize only the liquid state portion of the gas-liquid state, so that it is possible to quickly generate water vapor. .

  In particular, according to the second aspect of the present invention, since the water pipe is arranged along the entire surface of at least the side of the can body inside the heat insulating material, the side surface of the can body It is possible to uniformly absorb the heat of the entire heat insulating material disposed on the wall. As a result, the thickness of the heat insulating material on the side surface of the can body can be reduced over the entire surface, and the fuel cell module can be reduced in size and the installation area can be reduced.

  On the other hand, according to the third aspect of the present invention, an exhaust pipe for exhausting exhaust gas generated by a power generation reaction is disposed in the can body, and the steam generator is provided in the exhaust pipe. The heat of the exhaust gas is easily received by the steam generator. As a result, even if the capacity of the water vapor generator is reduced, it becomes possible to sufficiently generate water vapor, so that the water vapor generator can be further reduced in size.

According to the invention of claim 4, the fuel cell module has an output per volume of the outer can body of 5000 W / cm ³ or more, or an output per surface area of the outer can body of 1000 W / cm ² or more. Therefore, the output of the fuel cell module is high and the amount of exhaust heat of the fuel cell stack is large. For this reason, it becomes possible to maintain the fuel cell module in a heat-independent state by the heat insulating material whose temperature has been lowered by the heat absorption of the water pipe absorbing the heat and reducing the temperature inside the can.

It is a top view which shows one Embodiment of the fuel cell module which concerns on this invention. FIG. 2 is a cross-sectional view taken along line AA ′ in FIG. 1. FIG. 3 is a cross-sectional view taken along line BB ′ in FIG. 2. It is an expanded sectional view of the C section of FIG.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
First, as shown in FIG. 2, the fuel cell module of the present invention is a box-shaped can body composed of an inner can body 1 and an outer can body 3 that covers the inner can body 1 through a heat insulating material 2. 4, a water pipe 5 disposed inside the heat insulating material 2, a plurality (four in the figure) of the fuel cell stack 6 and the reformer 24 disposed inside the can body 4, and the bottom of the can body 4 An exhaust pipe 7 disposed in the exhaust pipe 7 and a water vapor generator 8 disposed in the exhaust pipe 7 are schematically configured.

  As shown in FIG. 4, the fuel cell stack 6 has fuel cells on the outside of a power generation cell 12 in which a fuel electrode layer (anode) 10 and an air electrode layer (cathode) 11 are arranged on both surfaces of a solid electrolyte layer 9. An electrode current collector 13 and an air electrode current collector 14 are arranged, and a plurality of single cells 16 in which separators 15 are arranged outside these current collectors 13 and 14 are stacked in the vertical direction.

  The power generation cells 12 of the fuel cell stack 6 are formed in a sealless structure in which no gas leakage prevention seal is provided on the outer periphery.

  Here, the solid electrolyte layer 9 is a moving medium for oxide ions and at the same time functions as a partition wall for preventing the fuel gas and air from being in direct contact with each other, and thus has a dense structure that is gas-impermeable. The solid electrolyte layer 9 is a material that has high oxide ion conductivity, is chemically stable under conditions from the oxidizing atmosphere on the air electrode layer 11 side to the reducing atmosphere on the fuel electrode layer 10 side, and is resistant to thermal shock. As a material satisfying such requirements, it is composed of stabilized zirconia (YSZ) to which yttria is added.

Moreover, both the fuel electrode layer 10 and the air electrode layer 11 that are electrodes must be made of a material having high electron conductivity. Therefore, the material of the fuel electrode layer 10 is composed of a metal such as Ni or Co, or a cermet such as Ni—YSZ or Co—YSZ. The material of the air electrode layer 11 is a high temperature around 700 ° C. The metal is unsuitable because it must be chemically stable in an oxidizing atmosphere of LaMnO ₃ or LaCoO ₃ having electronic conductivity, or a part of these La is substituted with Sr, Ca, etc. It is composed of a solid solution (LSM, LSC, SSC, etc.).

  Further, the fuel electrode current collector 13 is composed of a sponge-like porous sintered metal plate such as a nickel-based alloy, and the air electrode current collector 14 is also a sponge-like porous sintered metal such as a silver-based alloy. It consists of a plate. The sponge-like porous sintered metal plate has a current collecting function, a gas permeation function, a uniform gas diffusion function, a cushion function, a thermal expansion difference absorption function, and the like, and is therefore suitable as a multifunctional current collector material.

  On the other hand, the separator 15 is made of a metal material such as stainless steel. In addition, it is preferable to use a separator 15 on which a silver plating film is formed that maintains a good conductivity with little increase in electrical resistance at a low temperature and medium temperature operation of 700 ° C. or higher.

  The separator 15 has a function of electrically connecting the power generation cells 12 and supplying gas to the power generation cells 12. The fuel gas is introduced by introducing hydrogen as a fuel gas from the outer periphery of the separator 15. A fuel gas discharge hole 18 for discharging from the surface of the separator 15 facing the fuel electrode layer 10 through the passage 17, and air as an oxidant gas is introduced from the outer periphery of the separator 15 through the oxidant gas passage 19. An oxidant gas discharge hole 20 that is discharged from the surface of the separator 15 facing the air electrode layer 11 is formed.

  The fuel cell stack 6 is configured by stacking a plurality of single cells 16 including the power generation cells 12 and the separators 15, placing flanges on the uppermost side and the lowermost side in the stacking direction, and tightening with bolts. .

  On the other hand, the water pipe 5 functions also as a heat exchanger that absorbs the heat of the heat insulating material 2, and as shown in FIGS. 1 and 3, the water pipe 5 is introduced below the can body 4 and branched. Inserted from the four corners of the bottom of the body 4 into the inside of the heat insulating material 2 on the side of the can 4, toward the top of the can 4, meandering along the entire top of the can 4 After that, the water vapor is generated so as to move to the side surface of the can body 4 and to meander along the entire side surface of the can body 4, toward the bottom side again, and to the exhaust pipe 7 on the bottom side. It is connected to the inlet side of the vessel 8.

  The steam generator 8 is a heat exchanger for obtaining steam necessary for the reforming reaction of the reformer 4, and the outlet side of the steam generator 8 is connected to one end of the steam supply pipe 22.

  The other end of the water vapor supply pipe 22 is connected to a hydrocarbon gas supply pipe 23 into which hydrocarbon gas is introduced from the outside of the can 4.

  The hydrocarbon gas supply pipe 23 is connected to the inlet side of the reformer 24 arranged in the vicinity of the fuel cell stack.

  The reformer 24 is filled with a Ni (nickel) -based or Ru (ruthenium) -based reforming catalyst for hydrocarbons, and the outlet side of the reformer 24 is separated via a fuel gas supply pipe 21. It is connected to the inlet side of 15 fuel gas passages 17.

  Further, in the can body 4, an oxidant gas supply pipe (not shown) for supplying air from the outside of the can body 4 to the air electrode layer 11 of the fuel cell stack 2 is provided. One end of the supply pipe is connected to the inlet side of the oxidant gas passage 19 of the separator 15.

  In the fuel cell module configured as described above, during operation, hydrocarbon gas (for example, city gas) is supplied to the hydrocarbon gas supply pipe 23, water is supplied to the water pipe 5, and oxidant gas supply pipe (not shown) is supplied. Supply air respectively.

  Then, the water pipe 5 absorbs the heat of the heat insulating material 2, and the supplied water is heated to about 100 ° C., so that a part of the water is vaporized to the water vapor generator 8. Supplied.

  Then, the water vapor generator 8 absorbs the heat of the exhaust gas exhausted to the exhaust pipe 7, and the liquid portion of the supplied gas-liquid water is rapidly heated, so that all the water becomes water vapor. It is supplied to the supply pipe 22.

  Next, in a portion where the hydrocarbon gas supply pipe 23 and the water vapor supply pipe 22 are connected, the water vapor and the hydrocarbon gas are merged and mixed, and supplied to the reformer 24.

  Then, the reformer 42 absorbs the exhaust heat of the fuel cell stack and the heat of the exhaust gas, and the reforming reaction is performed, so that the supplied mixed gas is a hydrogen-rich fuel gas composed of hydrogen, carbon dioxide, and water vapor. Thus, the fuel gas is supplied to the fuel gas passage 17 through the fuel gas supply pipe 21.

  On the other hand, air supplied from an oxidant gas supply pipe (not shown) at the time of startup is supplied to the oxidant gas passage 19 of the separator 15 of each single cell 16.

  The hydrogen and air respectively supplied to the gas passages 17 and 19 are discharged toward the power generation cell 12 from the fuel gas discharge hole 18 and the oxidant gas discharge hole 20 at the substantially central portion of the separator 15, and are collected. By passing through the electric bodies 13, 14, the electric power layers 12 spread over the entire surface of the fuel electrode layer 10 and the air electrode layer 11 while being diffused in the outer peripheral direction of the power generation cell 12.

  And in power generation cell 12 of a plurality (four sets in a figure) fuel cell stack 6, power generation reaction occurs, and predetermined power is obtained.

At this time, in the high power type fuel cell module in which the plurality (four sets in the figure) of the fuel cell stacks 6 are arranged, the output per volume of the outer can body 3 is 5000 W / cm ³ or more. The output per surface area is 1000 W / cm ² or more.

  Further, since the four sets of fuel cell stacks 6 generate heat during the power generation reaction, and each of the fuel cell stacks 6 exhausts high-temperature heat, the amount of heat in the can 4 with respect to the amount of heat exhausted. There is a tendency to overheat.

  On the other hand, the fuel cell module of the present embodiment having the above configuration is between the inner can body 1 and the outer can body 3, and inside the heat insulating material 2, the side surface of the can body 4 and the top plate. Since the water pipe 5 is arranged along the entire surface, the water pipe 5 uniformly absorbs the heat of the entire heat insulating material 2 to reduce the temperature of the entire heat insulating material 2. As a result, even in a high-power fuel cell module with excessive heat, the heat in the can 4 is absorbed by the entire heat insulating material 2 whose temperature has been lowered, thereby reducing the temperature in the can 4. It becomes possible to set it as 500 degreeC-600 degreeC of predetermined temperature.

  Further, since the water pipe 5 absorbs the heat of the heat insulating material 2 that has absorbed the heat in the can, the heat insulating material 2 is sufficiently thin even if it is formed thinner than the conventional fuel cell module. It becomes possible to insulate heat. Thereby, since the can body 4 can be reduced in size, the can body can be reduced in size, and as a result, the fuel cell module can be reduced in size.

  On the other hand, since the water pipe 5 is surrounded by the heat insulating material 2, it does not directly absorb the heat in the can 4, and absorbs only the heat of the heat insulating material 2 arranged around the water pipe 5. . And since the water supplied to the water pipe 5 is always flowing at a predetermined water pressure and flow rate, even if the temperature of the heat insulating material 2 is a temperature at which water vaporizes (about 150 ° C. to 200 ° C.), All are not vaporized, part is vaporized, and the remaining part is in a gas-liquid state that maintains the liquid state. As a result, it is not necessary for the steam generator 8 to vaporize all the water, and it is sufficient to vaporize only the liquid state portion of the gas-liquid state. Become.

  Further, since the water pipe 5 is arranged along the side surface of the can body 4 and the entire surface of the top plate portion inside the heat insulating material 2, the heat insulation provided on the side surface of the can body 4 and the top plate portion. It is possible to absorb the heat of the entire material uniformly. As a result, the thickness of the heat insulating material 2 can be reduced over the entire surface, and the fuel cell module can be miniaturized and the installation area can be reduced.

  On the other hand, since the steam generator 8 is provided in the exhaust pipe 7 that exhausts the high-temperature exhaust gas generated by the power generation reaction, the steam generator 8 is easily in the state of receiving heat of the exhaust gas. For this reason, even if the capacity of the water vapor generator 8 is reduced, it is possible to sufficiently generate water vapor, leading to miniaturization of the water vapor generator 8, and as a result, the fuel cell module can be miniaturized. .

The fuel cell module is of a high output type with an output per volume of the outer can body 3 of 5000 W / cm ³ or more and an output per surface area of the outer can body 3 of 1000 W / cm ² or more. The fuel cell stack 6 (four sets in the figure) is in a state of exhausting heat and a large amount of exhaust heat. For this reason, it is possible to maintain the fuel cell module in a heat-independent state by the heat insulating material 2 whose temperature has been lowered by the heat absorption of the water pipe 5 absorbing the heat and reducing the temperature in the can 4. Become.

  In addition, about the management of the water piping 5, it is not restricted to this embodiment, The surface which arrange | positions the water piping 5 should be selected suitably according to the output of a fuel cell module, the installation location and installation area of a fuel cell module. Can do.

DESCRIPTION OF SYMBOLS 1 Inner can body 2 Heat insulating material 3 Outer can body 4 Can body 5 Water piping 6 Fuel cell stack 7 Exhaust pipe 8 Water vapor generator 12 Power generation cell 15 Separator

Claims (4)

The power generation cell is configured by alternately stacking power generation cells and separators inside a box-shaped can body configured by an inner can body and an outer can body covering the inner can body with a heat insulating material. In a fuel cell module provided with a water vapor generator that generates a water vapor by introducing water and arranging a fuel cell stack that generates a power generation reaction by supplying a reactive gas to
Supplying the water to the water vapor generator between the inner can body and the outer can body, along the surface of the can body, inside the heat insulator, and heat of the heat insulator A fuel cell module comprising a water pipe for absorbing heat.   2. The fuel cell module according to claim 1, wherein the water pipe is arranged along the entire side surface of the can body at least inside the heat insulating material. 3.   The fuel cell according to claim 1 or 2, wherein an exhaust pipe for exhausting the exhaust gas generated by the power generation reaction is disposed in the can body, and the steam generator is provided in the exhaust pipe. module. The fuel cell module has an output per volume of the outer can body of 5000 W / cm ³ or more and an output per surface area of the outer can body of 1000 W / cm ² or more. The fuel cell module according to any one of the above.

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