JP5418801B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell for generating power by housing a cell stack formed by stacking solid oxide cell units in a case and separating the cell stack and the case from each other and allowing two kinds of gases to flow therethrough. .

Conventionally, this type of fuel cell is disclosed in Patent Document 1.
A fuel cell disclosed in Patent Document 1 is provided with a combustor that mixes and burns exhaust fuel and exhaust air discharged by a power generation operation of a solid oxide fuel cell, and is disposed in the combustor. And a first heat recovery unit that generates steam or warm water.
JP 2003-132922 A

  However, in the above conventional fuel cell, by providing a heat exchanger that performs heat exchange between the anode and cathode introduction gas, the temperature difference between the anode introduction gas and the cathode introduction gas is reduced, and the cell of the cell stack Although the thermal stress can be reduced by reducing the difference between the anode gas temperature and the cathode gas temperature separated from each other, there is a problem in that the heat exchanger is provided separately from the cell stack, so that the compactness is lacking.

  Therefore, the present invention can achieve a uniform temperature distribution in the cell stack by reducing the temperature difference between the two kinds of gases flowing separately from each other in the cell stack and the case while reducing the size. The purpose is to provide fuel cells.

A fuel cell according to the present invention for solving the above-described problems includes a case in which a cell stack formed by stacking solid oxide cell units is housed in a case, and two types of gas are contained in the cell stack and the case. The power generation is performed by separating them from each other and distributing them.
In the present invention, a heat exchanger that performs heat exchange between two kinds of gases is disposed along a gas flow path that reaches the cell stack of any one of the gases flowing into the case.

  According to the present invention, the temperature distribution in the cell stack can be made uniform by reducing the temperature difference between the two kinds of gases flowing separately from each other in the cell stack and the case while reducing the size. it can.

  The best mode for carrying out the present invention will be described below with reference to the drawings. 1A and 1B show a fuel cell according to a first embodiment of the present invention, in which FIG. 1A is a plan sectional view and FIG. 1B is a sectional view taken along line II shown in FIG.

A fuel cell A1 according to an embodiment of the present invention includes a cell stack B in which a plurality of solid electrolyte cell units 10... Are stacked with a gap s and a heat exchanger 20 that is a temperature difference mitigating means. Is housed in.
The “gap s” is used to circulate one of the two kinds of gases between adjacent solid electrolyte cell units (hereinafter simply referred to as “cell units”) 10. .

One gas described above is passed through the case 30 and the other gas is passed through the cell stack B separately from each other.
In the present embodiment, one gas is air and the other gas is hydrogen (fuel gas), but it goes without saying that one gas may be hydrogen (fuel gas) and the other gas may be air. .

The case 30 has an airtight cylindrical shape in which a peripheral plate 33 is formed so as to surround the entire circumference of the bottom wall 31 and the upper wall 32 that are circular in plan view.
In the peripheral plate 33, a gas introduction part 34 for introducing one gas into the case 30 and a gas discharge part 35 for discharging one gas introduced into the case 30 form the cell stack B. It is arrange | positioned at the both sides which pinch | interpose. In other words, it is arranged on a diameter line O2 passing through the central axis O1 of the cell stack B.

The gas introduction part 34 has a vertically long rectangular parallelepiped shape defined by the circumferential plate 33, the circumferential plates 34a, 34b, 34c, the top plate 34d, and the bottom plate 34e, and an introduction pipe 36 is connected to the top plate 34d. ing.
A square opening 33 a is formed in the peripheral plate 33 facing the gas introduction part 34.

In the gas introduction part 34, the heat exchanger C1 which is a temperature difference relaxation means for relieving the temperature difference between two types of gases is disposed. In other words, the heat exchanger C1 is disposed along the gas flow path γ reaching the cell stack B of one gas flowing into the case 30.
That is, disposing the heat exchanger C <b> 1 in the gas introduction part 34 is synonymous with housing the heat exchanger C <b> 1 in the case 30.
The gas flow path γ is shown in FIG. 1 as a straight arrow, but actually has a certain flow path cross section.

  The gas discharge part 35 is a cylindrical tube connected to the outer surface of the peripheral plate 33 of the case 30, and a rectangular opening 33 b is formed at a connection portion between the cylindrical tube and the peripheral plate 33. Hereinafter, the gas discharge part is referred to as a gas discharge pipe 35.

The heat exchanger C1 has a configuration in which heat exchange tubes 41 for circulating the other gas and exchanging heat with one gas are arranged in a lattice shape in a vertically long cylindrical case 40. . That is, one gas flowing into the gas introduction part 34 from the introduction pipe 36 flows into contact with each heat exchange tube 41 so that heat exchange between the two kinds of gases is performed.
The heat exchange tube 41 is obtained by applying corrosion-resistant plating to the inner and outer walls of the chromium-copper composite material, thereby improving thermal conductivity and corrosion resistance.

  An inflow port 40a for allowing the other gas to flow into the case 40 is formed at the lower portion of the case 40, and an outflow port 40b for allowing the gas flowing into the case 40 to flow out is formed at the upper portion. Has been.

  A pipe (not shown) for guiding the other gas sent from the vaporizer 45 and the reformer 50 is connected to the inflow port 40a, and the other outflowing through the heat exchanger C1 is connected to the outflow port 40b. Pipes (not shown) for guiding the gas to a cell stack B, which will be described in detail later, are connected.

As the material for the heat exchange tube 41, a material having high conduction heat transfer, such as copper, is suitable. However, from corrosion resistance, copper and stainless clad materials, corrosion-resistant coating, corrosion-resistant plating, and heat with the cell By using a chromium-copper composite material with a thermal expansion coefficient that is almost equivalent to that of ferritic stainless steel that is compatible with the cell stack B and that has a higher thermal conductivity than stainless steel, the heat exchange efficiency is improved. Can be increased.
The above-described chromium-copper composite material can also maintain heat exchange performance for a long period of time by applying corrosion-resistant coating or corrosion-resistant plating as a clad material with stainless steel to improve the corrosion resistance.

In addition, by exchanging heat between two kinds of gases, the other gas at a high temperature is cooled with one gas at a low temperature, and the temperature difference between both gases is heated by heating one gas. The stress can be relaxed and the temperature difference between the two gases separating the cells of the cell stack can be reduced to reduce the thermal stress.
Furthermore, by reducing the temperature difference between the two gases, the temperature of the electrode is lowered too much by one of the low temperature gases in the cell stack B, thereby deactivating the electrochemical reaction of the electrode or increasing the overvoltage. Can be prevented.
Furthermore, in the case of a high load operation in which the heat generation amount is higher than the heat dissipation amount of the cell stack B, and the temperature of both gases is relaxed by the heat exchange and introduced into the cell stack B. In the case where a gas having a temperature lower than the operating temperature of B can be introduced, heat can be removed from both electrode surfaces by convective heat transfer by both gases, so that the cooling performance can be improved. The temperature distribution inside the cell stack B can be relaxed.

By the way, the above-described cell units 10... Have the in-unit current collector 80 and the flow path forming body 90 in the gap k formed between the cell plate 60 on which the solid electrolyte cell 50 is disposed and the separator 70. It is in the shape of an enclosed hollow disk.
Further, the external unit current collector 100 is disposed on the lower surface of the cell plate 60, and they are coaxially aligned around the axis O1.

The cell plate 60 has a circular stepped portion 61 having a height at which the gap s described above is formed between other cell units 10 adjacent to the cell unit 10, and protrudes downward from the center of the circular substrate 62. A peripheral wall 63 is inclined upward at the peripheral edge.
In the circular stepped portion 61, through holes 64, 65,... Having the same diameter as those are formed at positions corresponding to gas inflow holes 91 and gas outflow holes 94 formed in a flow path forming body 90 described later. ing.

  The solid electrolyte type cell 50 is formed in a circular shape in which an anode electrode (fuel electrode) and a cathode electrode (air electrode) are arranged on both upper and lower sides of an electrolyte (both not shown), and a cell plate with an axis O1 as a center. 60.

The separator 70 is provided with a circular stepped portion 71 having a height at which the above-described gap s is formed between the adjacent cell unit 10 and projecting upward at the center of the circular substrate 72. A peripheral wall 73 is inclined downward at the peripheral edge.
In the circular stepped portion 71, through holes 74, 75,... Having the same diameter as the gas inflow holes 91 and gas outflow holes 94 formed in the flow path forming body 90 are formed. .

  By stacking a plurality of the cell units 10 described above, the circular stepped portion 61 of the cell plate 60 and the circular stepped portion 71 of the separator 70 come into contact with each other, and thereby the gap s between the cell units 10 and 10 stacked adjacent to each other vertically. Is formed.

  The flow path forming body 90 is interposed between the circular step portions 61 and 71 of the cell plate 60 and the separator 70, and an inflow hole 91 for allowing one gas to flow into the cell unit 10, and the cell unit 10. An outflow hole 94 is formed to allow one of the gases flowing into the inside to flow out.

  The in-unit current collector 80 is formed by forming a porous body such as conductive foam metal or felt into an annular shape.

  In the cell plate 60 and the separator 70, the edges of the peripheral walls 63 and 73 are brought into contact with each other, whereby a gap k serving as a gas flow path is defined between them, and the unit is formed in the gap k. An inner current collector 80 is disposed.

  The unit external current collector 100 is formed by, for example, forming a metal mesh made of Inconel (registered trademark) into an annular shape, and the peripheral portion thereof is joined to the cell plate 60 or the separator 70. However, the material may be high Cr stainless steel such as SUS430, Crofer22APU, but is not limited thereto. Moreover, although the form of a collector can use a metal mesh, felt, a nonwoven fabric, a leaf | plate spring, etc., it is not restricted to this.

The cell stack B is configured by stacking a plurality of the cell units 10 described above, and is sandwiched and held between the upper flange 110 and the lower flange 120.
The upper flange 110 is a circular plate in plan view in which a flange portion 112 having the same diameter as that of the cell unit 10 is formed on the peripheral wall 111a of the cylindrical holding portion 111 having the same diameter as the circular step portions 61 and 71 described above. It is of shape.
A through hole 113 having the same diameter as the inflow hole 91 is formed in the center of the pressing portion 111.

The lower flange 120 has a circular shape in a plan view in which a flange portion 122 having the same diameter as the cell unit 10 is formed on the peripheral wall 121a of the cylindrical holding portion 121 having the same diameter as the circular step portions 61 and 71. It is.
A through-hole 123 having the same diameter as the gas outflow hole 94 is formed in the holding portion 121 so as to face the holding portion 121.

In the cell stack B having the above-described configuration, a plurality of cell units 10 are sandwiched between the upper flange 110 and the lower flange 120 and an insulating washer 131 is fitted, and stud bolts are inserted into the through holes 113 of the upper flange 110. 130 is inserted.
And the cell unit 10 ... is clamped elastically by screwing the lower end part of the thread part 130a of the stud bolt 130 into the lower flange 120.

Regarding the operation of the fuel cell having the above-described configuration, heat exchange between two types of gases will be mainly described.
When the other gas fed through the vaporizer 45 and the reformer 46 passes through the heat exchange tubes 41 of the heat exchanger C1, the other gas exchanges into the heat exchange tubes 41 from the introduction pipe 36. When one gas that has flowed into the gas inlet 34 flows into contact with each other, heat exchange between the two types of gases is performed.

One gas after the heat exchange is performed flows toward the gas discharge pipe 35 through the gap s of the cell stack B.
Thereby, the other gas discharged from the reformer is cooled by the other gas, and the other gas is preheated, and the heat exchanger C1 is provided on the other gas inflow side of the cell stack B. By providing the heat exchanger C1 and the cell stack B in the case, a cell that tends to be relatively low in temperature compared to the average temperature of the cell stack B mainly due to heat transfer between the heat exchanger C1 and the cell stack B. The other gas inflow region of the stack B can be warmed. For this reason, the temperature distribution in the plane of the cell unit 10 forming the cell stack B can be made uniform, and the inside of the stack structure B can be suppressed to a desired temperature difference.
Further, since the heat exchanger C1 is disposed in the gas introduction part 34, the fuel cell A1 can be downsized.

  Next, a fuel cell A2 according to a second embodiment of the present invention will be described with reference to FIG. 2A is a plan sectional view of the fuel cell A2 according to the second embodiment of the present invention, and FIG. 2B is a control unit for controlling the flow rate increasing / decreasing valve actuator. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and detailed description is abbreviate | omitted.

In the fuel cell A2 according to the second embodiment, the flow rate increasing / decreasing valve actuators 135 and 135 that form part of the gas flow rate increasing / decreasing unit D that increases or decreases the flow rate of one of the gases after heat exchange reach the cell stack B. The fuel cell A1 is different from the fuel cell A1 described above in that it is disposed in the gas flow path γ.
The gas flow rate increase / decrease part D is for diverting a part of one gas after heat exchange to the outside of the gas flow path γ before reaching the cell stack B.
In this embodiment, flow rate increasing / decreasing valve actuators 135, 135 for increasing / decreasing the amount of gas to be diverted are arranged in the diverter pipes 137, 137 arranged on the downstream side in the gas flow direction of the heat exchanger C1. Specifically, it is as follows.

  The gas introduction part 136 has a vertically long rectangular parallelepiped shape defined by a peripheral plate 33, side plates 136a, 136b, 136c, a bottom plate 136d, and a top plate (not shown). (Not shown) is connected, and the peripheral plate 33 is formed with a rectangular opening 33a facing the gas introduction part 136.

  In the gas introduction part 136, the heat exchanger C1, which is a temperature difference reducing means for reducing the temperature difference between one gas and the other gas, is disposed in the fuel cell A1. It is the same.

The flow dividing pipes 137 and 137 are on an axis O3 orthogonal to the central axis O1, and the side plates 136a and 136c are provided with the mutual inlets 137a and 137a, respectively. Increase / decrease valve actuators 135 and 135 are provided, respectively.
The flow rate increasing / decreasing valve actuators 135 and 135 are connected to the output side of the control unit 138 that is responsible for the control center of the fuel cell A2, and are opened and closed by a drive signal output from the control unit 138. Yes.
That is, the control unit 138 has a function of increasing or decreasing the flow rate of the gas to be diverted according to the required output of the fuel cell by executing a required program (this is referred to as “gas flow rate increasing / decreasing means”). .

On the input side of the control unit 138, information necessary for opening / closing control of the flow rate increasing / decreasing valve actuators 135, 135 is input in addition to various necessary information, and a drive signal corresponding to the input information is sent. It outputs to the valve actuators 135 and 135 for flow volume increase / decrease.
As described above, the gas flow rate increasing / decreasing unit D shown in the present embodiment includes the control unit 138 and the flow rate increasing / decreasing valve actuators 135 and 135.

By providing the gas flow rate increase / decrease part D, it is possible to remove excess heat of the gas and keep the temperature of the cell stack at a desired temperature. In particular, in the case of an on-vehicle fuel cell, it is necessary to make a sudden change from low load operation to high load operation.
In such a case, excessive heat is applied to the reformer to reform a large amount of fuel, so that the reformed gas from the reformer becomes hotter than during steady operation during sudden fluctuations, and the cell stack is subjected to a high load. Since heat generation also increases, it is difficult to keep the cell stack within a desired temperature range due to sudden load fluctuations, and it has not been possible to follow sudden load fluctuations.
However, by exchanging heat between the gases described above, the temperature of the gas is lowered before being introduced into the cell stack, and part of one gas after exchanging heat with the other gas is exhausted before the introduction of the stack. By doing so, excess heat carried by the other reformed gas can be exhausted, and the responsiveness to sudden load fluctuations can be improved.

  A fuel cell A3 according to a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a plan sectional view of a fuel cell A3 according to the third embodiment of the present invention. In addition, about the thing equivalent to what was demonstrated in each embodiment mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

The fuel cell A3 according to the third embodiment is different from the fuel cell A1 described above in the shape of the gas introduction part and the configuration of the heat exchanger.
The gas introduction part 140 has a vertically long cubic shape in a plan view substantially divided by the peripheral plate 33, the side plates 140a, 140b, 140c, the bottom plate 140d, and a top plate (not shown), and the top plate is similar to the above. An introduction pipe (not shown) is connected.
The side plates 140a and 140c are formed so that the interval between the side plates gradually increases from the upstream side to the downstream side of the gas flow path. As a result, one gas introduction part of the cell stack B can be widened, and by slowing down the flow velocity of the one gas through the unit gap s, the cell stack B can be rapidly cooled with one gas. Can be prevented from occurring.

In the gas introduction part 140, a heat exchanger C2 which is a temperature difference relaxation means for relaxing a temperature difference between two kinds of gases is disposed. In other words, the heat exchanger C2 is arranged in the gas flow path γ reaching the cell stack B of one gas flowing into the case 30.
The heat exchanger C2 is configured such that heat exchange tubes 41 for circulating one gas and exchanging heat with the other gas are arranged at a predetermined interval. The gas flow paths γ are arranged so that the heat exchange heat transfer area increases from the upstream side to the downstream side in the flow direction. From this, the heat exchange upstream side is used to preheat one gas, while the heat exchange downstream side can transfer heat to the cell stack B through a wide heat transfer area portion of the heat exchanger C2. By preventing the temperature drop on the introduction side of the cell stack B, the temperature distribution of the cell stack B can be relaxed.

In the present embodiment, the heat exchange tubes 41 are arranged so that the distance from each other becomes closer from the upstream side to the downstream side in the flow direction of the gas flow path γ.
In other words, the number of the heat exchange tubes 41 arranged per unit area is increased from the upstream side to the downstream side in the flow direction of the gas flow path γ. This makes it possible to increase the pressure loss on the downstream side of the heat exchange by increasing the space between the heat exchange tubes on the downstream side of the heat exchange. It can be made uniform in the inward direction.

Specifically, heat exchanging tubes 41 are arranged in four large and small circles centered on the central axis O1 and arranged from those far from the cell stack B to those close to the cell stack B. The interval between the heat exchange tubes 41 is narrowed.
If the heat exchange tubes 41 arranged in adjacent rows are arranged so as not to overlap in the direction along the diameter line O2, the flow of one gas to each heat exchange tube is favorably performed, It can contribute to the improvement of heat exchange efficiency.

  A fuel cell A4 according to a fourth embodiment of the present invention will be described with reference to FIG. 4A and 4B show a fuel cell according to a fourth embodiment of the present invention. FIG. 4A is a plan sectional view, and FIG. 4B is a sectional view taken along the line II shown in FIG. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and detailed description is abbreviate | omitted.

  A fuel cell A4 according to a fourth embodiment of the present invention houses a cell stack B and a heat exchanger C3 that is a temperature difference mitigating means in a case 30, and details will be described later in the case 30. The main configuration is that a pair of gas guiding members 150 and 150 are provided.

The case 30 is formed in an airtight cylindrical shape surrounding the peripheral plate 33 over the entire circumference of a bottom plate 31 and a top plate (not shown) that are circular in plan view.
A gas discharge portion 151 for discharging one of the gases introduced into the case 30 is disposed on the inside of the peripheral plate 33 and on the diameter line O2 passing through the axis O1. Gas introduction portions 152 and 152 for introducing one gas are disposed on both sides of the discharge portion 151.
In other words, heat exchange is performed between one gas discharged from the cell stack B and one gas introduced into the case 30 by adopting a structure in which the gas discharge portion 151 is included in the gas introduction portions 152 and 152. By carrying out, a part of heat generation of the cell stack B can be used for preheating one gas (air) flowing toward the cell stack B.

  The gas introduction part 152 is formed in a cylindrical shape, and an introduction hole 152a for introducing one gas into the case 30 is formed in multiple stages in the peripheral plate.

The gas discharge part 151 is formed in a cylindrical shape with the lower end closed, and is a peripheral plate of the gas discharge part 151. The gas discharge part 151 takes in and discharges one gas in the case 30 at a position facing the gap s of the cell unit B. Gas intake holes 151a... Are arranged in multiple stages.
In other words, the gas intake holes 151a are arranged in accordance with the stacking pitch of the cell units 10.

The gas guiding members 150 and 150 circulate one gas introduced from the gas introduction part 152 into the case 30 along the outer peripheral edge Ba of the cell stack B, and pass through the gap s of the cell stack B. It has a function of guiding to the discharge unit 151.
The base end portions of the gas guiding members 150 and 150 are connected to the gas discharge portion 151, and an opening region P for inducing one gas into the cell stack B is defined between the open end portions. ing.
The outer peripheral edge Ba of the cell stack B can be rephrased as the outer edge of the cell unit 10.

Specifically, the gas guiding members 150 and 150 are bent symmetrically about the diameter line O2 in plan view, and between the gas guiding members 150 and 150 and the inner surface of the peripheral plate 33 of the case 30. The flow passages α and α for flowing one gas are defined.
In the present embodiment, the flow paths α and α also form part of the gas introduction part 152.
In the present embodiment, the cell stack B is displaced along the diameter line O2 toward the gas discharge part 151, so that the flow paths α and α are heated from the gas discharge part 151. The width is gradually increased toward the exchanger C3.

  Heat that is a temperature difference mitigating means for mitigating the temperature difference between one gas and the other gas is located at the inner periphery of the case 30 and facing the opening region P of the gas guiding members 150 and 150. An exchanger C3 is provided. In other words, the heat exchanger C is disposed in the gas flow path γ reaching the cell stack B of one gas flowing into the case 30.

The heat exchanger C3 has a large and small size centered on a central axis O1 with a tube 41 for heat exchange for circulating one gas in the vertically long cylindrical case 40 and exchanging heat with the other gas. The configuration is arranged on an arc.
That is, one gas flowing into the case 30 from the gas introduction part 152 flows into the heat exchange tubes 41, so that heat exchange between the two types of gases is performed.

As described above, one gas introduced into the case 30 can be heat-exchanged via the heat exchanger C3, and one gas to be circulated through the cell stack B can be preheated.
In addition, since the gas discharge portion 151 and the gas guiding member 150 are close to the outer edge portion Ba of the cell stack B, from the unit external current collector, separator, cell plate, unit internal current collector, etc. in the cell stack B Heat can also be transmitted to the gas induction member 150, and a part of the heat generated by power generation is used for preheating one gas, so that the temperature of the cell stack B can be easily adjusted and the power generation performance can be stabilized. In particular, the direction in which the outer edge Ba flows and the direction in which the unit gap s flows are opposed to each other, so that the heat generated in the cell stack B causes the gas on the downstream side of the unit gap s, that is, The temperature distribution of the cell stack B can be relaxed by introducing one gas using the gas guiding member 150 from the region side.

  A fuel cell A5 according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a plan sectional view of a fuel cell according to the fifth embodiment of the present invention. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and detailed description is abbreviate | omitted.

In the fuel cell A5 according to the fifth embodiment, the configuration of the heat exchanger arranged in the flow path α is different from that shown in FIG.
In the heat exchanger C4, the heat exchange tubes 41 for circulating one gas and exchanging heat with the other gas are directed from the gas introduction part 152 toward the opening region P so as to be densely packed. In this configuration, α is arranged in two rows.
Specifically, the heat exchange tubes 41 are arranged on two large and small circles centered on the central axis O1. Among them, the heat exchange tubes 41 forming the inner row and the heat exchange tubes 41 forming the inner row are arranged so that the intervals gradually decrease from the gas introduction part 152 toward the opening region P. Has been.
With the above configuration, one gas that has flowed into the gas introduction section 152 flows into contact with each of the heat exchange tubes 41 to exchange heat between these two types of gases.
By adopting such a structure, the heat exchanger is arranged in the flow path α, so that the gas flow flowing through the outer edge portion Ba is disturbed, and the temperature distribution perpendicular to the gas flow direction is made uniform, so that the cell Exchange efficiency of heat passing from the stack B through the gas guiding member 150 can be improved.

  A fuel cell A6 according to a sixth embodiment of the present invention will be described with reference to FIG. 6A and 6B show a fuel cell according to a sixth embodiment of the present invention. FIG. 6A is a plan sectional view, and FIG. 6B is a sectional view taken along the line II shown in FIG. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and detailed description is abbreviate | omitted.

In the fuel cell A6 according to the sixth embodiment, the flow rate increasing / decreasing valve actuator 135 that forms a part of the gas flow rate increasing / decreasing unit D that increases or decreases the flow rate of the other gas after heat exchange is changed to a gas flow reaching the cell stack B. Arranged along the path γ.
The gas flow rate increase / decrease part D is for diverting a part of one gas after heat exchange to the outside of the gas flow path γ before reaching the cell stack B.
In the present embodiment, the flow rate increasing / decreasing valve actuator for increasing / decreasing the amount of gas to be diverted to the shunt pipe 160 which is the peripheral plate 33 of the case 30 and is disposed downstream of the heat exchanger C3 in the gas flow direction. 135 is arranged, specifically as follows.

A shunt pipe 160 is disposed at a position corresponding to the diameter line O2 in the peripheral plate 33, in other words, at a portion facing the opening region P formed by the open ends of the gas guiding members 150 and 150. .
The flow dividing pipe 160 is formed in a cylindrical shape, and the above-described flow rate increasing / decreasing valve actuator 135 is disposed therein.
The flow rate increasing / decreasing valve actuator 135 is connected to the output side of the control unit 138 equivalent to that described above, and is opened and closed by a drive signal output from the control unit 138.

  A fuel cell A7 according to a seventh embodiment of the present invention will be described with reference to FIG. 7A and 7B show a fuel cell according to a seventh embodiment of the present invention. FIG. 7A is a plan sectional view, and FIG. 7B is a sectional view taken along the line II shown in FIG. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and detailed description is abbreviate | omitted.

The fuel cell A7 according to the seventh embodiment has a configuration in which a heat exchanger C5 and a reformer 165 are disposed in a case 30.
The peripheral plate 33 of the case 30 includes a gas introduction part 170 for introducing one gas into the case 30 and a gas discharge part 171 for discharging one gas introduced into the case 30. Arranged on both sides of the stack B. In other words, it is arranged on a diameter line O2 passing through the central axis O1 of the cell stack B.

The gas introduction part 170 has a vertically long rectangular parallelepiped shape defined by the circumferential plate 33, the circumferential plates 170a, 170b, and 170c, the top plate 170d, and the bottom plate 170e, and an introduction pipe 172 is connected to the top plate 170d. ing.
In addition, a rectangular opening 33 a is formed in the peripheral plate 33 so as to face the gas introduction part 170.

  In the gas introduction part 170, a heat exchanger C5, which is a temperature difference mitigating means for mitigating a temperature difference between one gas and the other gas, is disposed. In other words, the heat exchanger C5 is disposed in the gas flow path γ reaching the cell stack B of one gas flowing into the case 30.

  The heat exchanger C5 has a configuration in which heat exchange tubes 41 for circulating one gas and exchanging heat with the other gas are arranged in two rows in a vertically long cylindrical case 40. . That is, one gas flowing into the gas introduction part 170 from the introduction pipe 172 is brought into flow contact with each heat exchange tube 41 so that heat exchange between these two kinds of gases is performed.

  The gas discharge part 171 has a vertically long rectangular parallelepiped shape defined by the peripheral plate 33, the peripheral plates 171a, 171b, and 171c, the top plate 171d, and the bottom plate 171e, and a discharge pipe 173 is connected to the top plate 170d. ing.

  The reformer 165 has a configuration in which catalyst reaction tubes 167 for performing reforming by circulating the other gas in a vertically long cylindrical cathode case 166 are arranged in a lattice pattern. That is, the other gas discharged from the cathode case 166 flows into contact with each catalyst reaction tube 167 so that heat exchange between the two types of gases is performed.

  By providing the reformer 165 in the case 30 on the gas discharge part 171 side, the stack stack heat of gas can be used as a cold heat source for reforming, and the temperature of the other gas can be adjusted. it can. Furthermore, by providing a large pressure loss on the exhaust side of one gas, the distribution distribution of the one gas between the cell units is relaxed, and the power generation characteristics between the cell units 10 and 10 become more uniform. Furthermore, by providing a reformer in the case, it is possible to achieve compactness, which is an important element for mounting in a limited space as in the case of in-vehicle use, while reducing heat dissipation and reducing thermal efficiency. improves.

  A fuel cell A8 according to an eighth embodiment of the present invention will be described with reference to FIG. 8A and 8B show a fuel cell according to an eighth embodiment of the present invention. FIG. 8A is a plan sectional view, and FIG. 8B is a sectional view taken along the line II shown in FIG. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and detailed description is abbreviate | omitted.

  The fuel cell A8 according to the eighth embodiment is mainly configured such that the cell stack B, the heat exchanger C3, the reformer 180, and the pair of gas induction members 150 and 150 are accommodated in the case 30. is there.

The case 30 is formed in an airtight cylindrical shape surrounding the peripheral plate 33 over the entire circumference of the bottom plate 31 and the upper plate 32 that are circular in plan view.
A gas discharge portion 190 for discharging one gas introduced into the case 30 is disposed on the diameter line O2 passing through the central axis O1 inside the peripheral plate 33, and the gas discharge is performed. Gas introducing portions 200 and 200 are disposed on both sides of the portion 190.

  The gas discharge section 190 is partitioned and formed into a substantially square cylindrical shape by the peripheral plate 33 and the side plates 190a and 190b, and a reformer 180 equivalent to the above is provided therein.

  The gas introduction portions 200 and 200 are partitioned and formed by a partition plate 201 provided upright with the side plates 190 a and 190 b therebetween, and one reaction gas is introduced into the case 30 in the partition plate 201. Introducing holes 201a, 201a are formed in a multi-stage structure.

  The reformer 180 has a configuration in which catalyst reaction tubes 182... For performing reforming by circulating the other gas in a vertically long cylindrical cathode case 181 are arranged in a lattice pattern. That is, the other gas discharged from the cathode case 181 flows into contact with each catalyst reaction tube 182 so that heat exchange between the two types of gases is performed.

A shunt pipe 160 is disposed at a position corresponding to the diameter line O2 in the peripheral plate 33, in other words, at a portion facing the opening region P formed by the open ends of the gas guiding members 150 and 150. .
The flow dividing pipe 160 is formed in a cylindrical shape, and the above-described flow rate increasing / decreasing valve actuator 135 is disposed therein.
The flow rate increasing / decreasing valve actuator 135 is connected to the output side of a control unit 138 equivalent to the control unit described above, and is opened and closed by a drive signal output from the control unit 138.

  A fuel cell A9 according to a ninth embodiment of the present invention will be described with reference to FIGS. 9A and 9B show a fuel cell according to a ninth embodiment of the present invention. FIG. 9A is an overall perspective view, and FIG. 9B is a cross-sectional view taken along the line II shown in FIG. FIG. 10 is an enlarged view of the heat exchanger C4. In addition, about the thing equivalent to what was demonstrated in embodiment mentioned above, the code | symbol same as them is attached | subjected and detailed description is abbreviate | omitted.

A fuel cell A9 according to a ninth embodiment of the present invention includes a stack heat exchanger complex E in which a heat exchanger C6 and cell stacks B and B equivalent to those described above are integrally formed, and a case 30 The main feature is that it is installed in the building.
In other words, the gas flow path is formed so that the flow direction of one gas flowing through the heat exchanger C6 and the flow direction of one gas flowing through the cell stack B face each other.

  The case 30 has an airtight cylindrical shape surrounding the peripheral plate 33 over the entire circumference of the bottom wall 31 and the upper wall 32 that are circular in plan view. The inside of the case 30 is vertically separated by partition plates 37 and 38. It is divided into three accommodation chambers 30a, 30b, 30c.

In the peripheral plate 33, the gas introduction part 210 and the gas discharge parts 220, 220 are arranged one above the other on one side across the stack heat exchanger complex E, and introduced from the gas introduction part 210 on the other side. Guidance sections 230 for guiding the one of these gases to the gas discharge sections 220 and 220 are provided.
In other words, the gas introduction part 210, the gas discharge parts 220 and 220, and the induction part 230 are disposed on the diameter line O2 passing through the central axis O1 of the stack heat exchanger complex E, and hence the cell stack B. Yes.

  The guide portion 230 is a vertical rectangular shape formed in communication between the storage chambers 30a, 30b, and 30c, and is not partitioned by the partition plates 37 and 38.

  In the present embodiment, the gas flow path β is formed so that the flow direction of one gas flowing through the heat exchanger C6 and the flow direction of one gas flowing through the cell stacks B and B face each other. . That is, the gas flow path β is formed by arranging the gas introduction part 210 and the gas discharge parts 220 and 220 on one side across the stack heat exchanger complex E described below, and the induction part 230 on the other side. Has been. In summary, the gas flow path β circulates in a substantially E shape in the left-right reverse direction when viewed from the front.

The stack heat exchanger composite E has a configuration in which two cell stacks B and B equivalent to those described above are turned upside down and a heat exchanger C6 is disposed between the cell stacks B and B. Is.
Hereinafter, of the two cell stacks B and B, the cell stack B disposed on the upper side is referred to as an upper cell stack, and the cell stack B disposed on the lower side is referred to as a lower cell stack.

The heat exchanger C6 shown in this embodiment is formed by stacking four heat exchange units 240 with a predetermined gap therebetween.
The heat exchange unit 240 has a hollow disk shape in which a flow path forming body 250 described later is accommodated in a gap m formed between two upper and lower heat exchange plates 241 and 241. It is the structure which mutually aligned coaxially as a center.

The heat exchanging plate 241 is made of a material having a high heat conduction efficiency, and it has a circular stepped portion 242 having a height at which the above-described required gap is formed between other adjacent heat exchanging units 240. The circular substrate 243 protrudes from the center, and the peripheral wall 244 is inclined at the periphery.
The circular stepped portions 242 and 242 are formed with through holes 242 a and 242 b having the same diameter as the gas inflow holes 250 a and 250 b formed in the flow path forming body 250. .

  The flow path forming body 250 is inserted between the circular stepped portions 242 and 242 of the heat exchanging plates 241 and 241, an inflow hole 250 a for allowing the other gas to flow into the heat exchanging unit 240, and heat An outflow hole 250b for allowing the other gas flowing into the exchange unit 240 to flow out is formed.

  The flow path forming body 250 is disposed between the circular stepped portions 242 and 242, and the heat exchange plates 241 and 241 are opposed to each other so that the peripheral walls 244 and 244 are joined to each other, thereby forming a gap m in the inside. The heat exchange unit 240 is obtained.

  In this embodiment, the supply for supplying the other gas to each heat exchange unit C6 between the upper two heat exchange units C6 and C6 and the upper two heat exchange units C6 and C6. They are stacked with the part 260 sandwiched therebetween.

  The feeding section 260 has an introduction pipe 261 for introducing the other gas protruding from the peripheral wall 260a, and an inflow hole 260b for allowing the other gas introduced from the introduction pipe 261 to flow in, It has a cylindrical shape with an outflow hole 260c for allowing the other gas that has flowed in to flow out.

The heat exchange operation by the heat exchanger C6 having the above-described configuration is as follows.
When the other gas fed through the introduction pipe 261 passes through each heat exchange unit 240, the one gas flowing from the gas introduction part 34 flows into the heat exchange plates 241 and 241. The heat exchange between the two types of gases is performed.

One gas after the heat exchange is performed flows toward the gas discharge parts 220 and 220 through the gap s1 of the heat exchange unit 240 and the guide part 230. Thereby, the temperature distribution in the plane of the cell unit 10 constituting the cell stack B can be made uniform, and the inside of the cell stack B can be suppressed to a desired temperature difference.
Further, since the heat exchanger C6 is interposed between the cell stacks B and B, the fuel cell A9 can be further reduced in size.

  That is, while the temperature of the introduction side of one gas of the heat exchanger C6 is low, the discharge side receives heat from the other gas and becomes high temperature. In addition, since one gas discharged through the cell stack B has a higher temperature than before flowing into the cell stack B, the cell unit is made to face the heat exchanger C6 and one gas flowing into the cell stack B. The temperature distribution in the B plane can be relaxed.

FIG. 11 shows a flowchart regarding another operation method according to the ninth embodiment of the present invention.
Step 1 (abbreviated as S1 in the figure, the same applies hereinafter) Recognizes the required output to the fuel cell and proceeds to Step 2.
In step S2, in accordance with the required output, the amount of heat of the other gas discharged from the reformer is predicted from the fuel input to the reformer and the operating temperature of the reformer. The amount of heat generated by is predicted, and the process proceeds to step 3.

In step 3, the amount of air necessary for power generation and sufficient to prevent the output from being reduced (air (oxygen) utilization rate of about 10 to 80%) is calculated, and the process proceeds to step 4.
In step S4, it is determined whether the representative temperature (for example, average temperature) of the cell stack falls within a desired range in the case of the above gas conditions, and if it is determined that it falls within the desired temperature, the process proceeds to step 5.

In step 5, heat is exchanged between the reformed gas and air, and the process proceeds to step 6.
In step 6, the bubble is closed by the flow rate adjusting bubble actuator, and all the air after heat exchange is introduced into the cell stack.
On the other hand, if it is determined in step 5 that the representative temperature of the cell stack is not within the desired range, the process proceeds to step 7.

In step 7, the amount of heat of the reformed gas from the reformer is calculated, the amount of air necessary for this is calculated, air is introduced, and the process proceeds to step 8.
In step 8, the reformed gas and the air are subjected to heat exchange to take away excess heat of the reformed gas, and the process proceeds to step 9.

In Step 9, the flow rate increasing / decreasing valve actuator is operated so that only the air amount necessary and sufficient for power generation is allowed to flow through the cell stack and the remaining air is discharged out of the cell stack.
Note that this operation method is common to all the embodiments including the flow rate increasing / decreasing valve actuator, and is not limited to the ninth embodiment.

The present invention is not limited to the above-described embodiments, and the following modifications can be made.
In the above embodiment, the heat exchanger has a configuration in which a plurality of circular tubes are arranged. However, the present invention is not limited to this, and fins for further improving the heat exchange efficiency are provided in the above tubes. The structure and tube & corrugate etc. can be applied.

Although described in detail above, in any case, each configuration described in each of the above embodiments is not limited to being applied only to each of the above embodiments, and the configuration described in one embodiment is not limited to other embodiments. It should be noted that the present invention can be applied mutatis mutandis or applied, and can be arbitrarily combined.

BRIEF DESCRIPTION OF THE DRAWINGS The fuel cell which concerns on 1st embodiment of this invention is shown, (A) is a plane sectional view, (B) is sectional drawing which follows the II line | wire shown to (A). (A) is a plane sectional view of the fuel cell according to the second embodiment of the present invention, and (B) is a control unit for controlling the flow rate increasing / decreasing valve actuator. It is a plane sectional view of fuel cell A3 concerning a third embodiment of the present invention. The fuel cell which concerns on 4th embodiment of this invention is shown, (A) is a plane sectional view, (B) is sectional drawing which follows the II line | wire shown to (A). FIG. 6 is a plan sectional view of a fuel cell according to a fifth embodiment of the present invention. The fuel cell which concerns on 6th embodiment of this invention is shown, (A) is a plane sectional view, (B) is sectional drawing which follows the II line | wire shown to (A). The fuel cell which concerns on 7th embodiment of this invention is shown, (A) is a plane sectional view, (B) is sectional drawing which follows the II line | wire shown to (A). The fuel cell which concerns on 8th embodiment of this invention is shown, (A) is a plane sectional view, (B) is sectional drawing which follows the II line | wire shown to (A). The fuel cell which concerns on 9th embodiment of this invention is shown, (A) is a whole perspective view, (B) is sectional drawing which follows the II line | wire shown to (A). It is an enlarged view of the heat exchanger shown in FIG. It is a flowchart regarding another operating method of the fuel cell according to the ninth embodiment of the present invention.

Explanation of symbols

10 Cell unit 12 In-unit current collector 30 Case 34, 240 Gas inlet 35 Gas outlet 41 Heat exchange tube 80 In-unit current collector 100 In-unit current collector 135 Flow rate increase / decrease valve actuators 165, 180 Reformer A1 to A9 Fuel cell B Stack structure Ba Outer peripheral edge C1 to C6 Temperature difference mitigation means (heat exchanger)
D Gas flow rate increase / decrease section s Gap

Claims (13)

In a fuel cell that houses a cell stack formed by stacking solid oxide cell units in a case, and performs power generation by allowing two types of gas to flow separately from each other in the cell stack and the case,
Fuel cell, wherein a heat exchanger for exchanging heat between the two types of gases mutually along the gas flow path to the cell stack of any of the above gas flowing into the casing is disposed . The case, among the two types of gas, the gas introducing portion for introducing one of the gas to be circulated inside the casing is formed, a heat exchanger that you have disposed on the gas introduction portion The fuel cell according to claim 1, wherein The heat exchanger is a tube in which heat exchange tubes for circulating the other gas and exchanging heat with the one gas are arranged at a predetermined interval, and these heat exchange tubes are arranged in one gas. The fuel cell according to claim 2 , wherein the heat exchange area is increased from the upstream side to the downstream side in the flow direction of the gas flow path. The fuel cell according to claim 3, wherein the heat exchange tubes are arranged so that a distance between each gas flow path is increased from the upstream side to the downstream side in the flow direction . The gas flow rate adjuster to increase or decrease the flow rate of one gas, a heat exchanger according to any one of claims 1 to 4, along the gas flow path to the cell stack, characterized in that arranged Fuel cell. 6. The fuel cell according to claim 5, wherein the gas flow rate increasing / decreasing unit diverts a part of the one gas after the heat exchange to the outside of the gas flow path before reaching the cell stack. Gas flow rate adjuster, the fuel cell according to claim 5 or 6, characterized in that have a gas flow rate adjusting unit for increasing or decreasing the flow rate of gas diverted in accordance with a required output of the fuel cell. The gas flow rate increasing / decreasing unit is characterized in that a flow rate increasing / decreasing valve actuator for increasing / decreasing the amount of gas to be shunted is disposed in a shunt pipe disposed on the downstream side in the gas flow direction of the heat exchanger. The fuel cell according to any one of claims 5 to 7 . The gas introduction part and the gas discharge part are arranged adjacent to each other, and one gas introduced into the case from the gas introduction part is circulated along the outer peripheral edge part of the cell stack, The fuel cell according to any one of claims 1 to 8, further comprising a gas guide member that guides the gas discharge unit through the gap . The fuel cell according to any one of claims 1 to 9, wherein at least one heat exchanger is arranged in a stacking direction of the cell units . At least one heat exchanger is arranged in the stacking direction of the cell units, and is a hollow disk shape in which a gap for flowing any one gas is formed between the upper and lower two heat exchange plates. The fuel cell according to claim 1 or 2 , wherein the fuel cell is stacked coaxially with the cell unit. And the flow direction of one of the gas flowing through the heat exchanger, to claim 10 or 11 the flow direction of the other gas and wherein the forming a gas flow path so as to face each other flowing through the cell stack The fuel cell as described. The fuel cell according to any one of claims 1 to 12 , wherein the reformer is disposed in the gas discharge portion .

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