JP4955913B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system including a fuel cell that generates power using a hydrogen-containing fuel gas containing hydrogen.

Conventionally, as a fuel cell system including a fuel cell that generates power using a hydrogen-containing fuel gas containing hydrogen, for example, there is one shown in Patent Document 1 or Patent Document 2.
Since the fuel cell has an appropriate operating temperature, it is necessary to control the temperature level and distribution so as to keep the temperature of the fuel cell within this operating temperature range.
Therefore, in the above fuel cell system, a gas or liquid cooling medium is circulated to prevent the temperature of the fuel cell from increasing and temperature control is performed.

On the other hand, there may be a case where the operating temperature of the fuel cell is set to a predetermined region of, for example, 300 ° C. or higher.
An example of a fuel cell having such a high temperature range as an operating temperature is disclosed in Patent Document 3. In this fuel cell, when the hydrocarbon-containing fuel gas is generated by reforming hydrocarbon or the like using a reformer, there is an advantage that the temperature of the hydrogen-containing fuel gas does not need to be significantly cooled. is there. This is because the hydrogen-containing fuel gas produced in the reformer is at a high temperature of 400 ° C. or higher, but the operating temperature of the fuel cell is also a high temperature equivalent thereto.

However, when an organic liquid refrigerant such as a hydrocarbon is used for temperature control of a fuel cell that operates at a high temperature as described above, problems such as carbonization may occur. Thus, the organic liquid refrigerant may be difficult to use from the viewpoint of heat resistance in a temperature range exceeding 300 ° C.
On the other hand, when a gaseous cooling medium is used, since the heat capacity is small, it is necessary to make the flow rate of the cooling medium very large, and when an appropriate amount of the cooling medium is used, the temperature is increased while circulating in the fuel cell. Since the temperature rises greatly, there is a problem that temperature distribution tends to occur in the fuel cell. Thereby, uniform temperature control of the fuel cell becomes difficult.

When a temperature distribution is generated inside the fuel cell, thermal stress is generated, which may reduce the durability of the fuel cell.
In addition, a local temperature drop in the fuel cell causes factors such as a decrease in electrolyte conductivity and hydrogen embrittlement, and a local temperature rise causes deterioration due to metal diffusion. It may cause a decrease in

JP 2003-151599 A Japanese Patent Laid-Open No. 2001-2223017 JP 2004-146337 A

  The present invention has been made in view of such conventional problems, and is intended to provide a fuel cell system capable of efficiently performing uniform temperature distribution control of a fuel cell having an operating temperature of 300 ° C. or higher. is there.

The present invention relates to a fuel cell system including a fuel cell that generates power at an operating temperature of 300 ° C. or higher using a hydrogen-containing fuel gas containing hydrogen.
The fuel cell system has a refrigerant circulation channel for circulating a cooling medium for cooling the fuel cell in a liquid state,
Upper Symbol cooling medium is made using an inorganic refrigerant in the liquid state at 300 ° C. or higher,
And a tank that is in communication with the refrigerant circulation channel and includes a heat exchange means for exchanging heat with the inorganic refrigerant,
The tank collects the inorganic refrigerant when the system is stopped, and heat-exchanges the inorganic refrigerant flowing through the refrigerant circulation passage by the heat exchanging means when the system is in steady operation. ( Refer to claim 1 and Example 7 ).

Next, the effects of the present invention will be described.
In the fuel cell system, an inorganic refrigerant is used as a cooling medium for cooling the fuel cell. Since the inorganic refrigerant is composed of an inorganic substance, it has excellent thermal stability and does not deteriorate even at a high temperature of 300 ° C. or higher.
Therefore, the inorganic refrigerant can sufficiently function as a cooling medium for controlling the temperature of the fuel cell in which the operating temperature is a predetermined region of 300 ° C. or higher.

The inorganic refrigerant can be kept in a liquid state at 300 ° C. or higher. Therefore, since the cooling medium can be circulated through the refrigerant circulation passage with a large heat capacity, the efficiency of heat exchange with the fuel cell can be increased. And since the temperature rise of the cooling medium while passing through the fuel cell can be suppressed, the temperature distribution inside the fuel cell can be made uniform.
In the present invention, the tank further includes a tank that is in communication with the refrigerant circulation flow path and includes heat exchange means for exchanging heat with the inorganic refrigerant. A configuration is adopted in which the refrigerant is collected and the inorganic refrigerant flowing through the refrigerant circulation passage is heat-exchanged by the heat exchanging means at the time of steady operation of the system.
Therefore, heat exchange can be performed for the cooling medium in the tank, and heat exchange efficiency can be improved.
Moreover, since the cooling medium collected in the tank has a small surface area, it is difficult to be cooled and solidification is suppressed. Therefore, for example, by collecting the cooling medium in the tank when the system is stopped, solidification of the cooling medium can be suppressed.
In addition, during steady operation of the system, the cooling medium can be sequentially sent to the tank, heat exchange can be performed in the tank, the temperature can be adjusted intensively, and the temperature-adjusted cooling medium can be circulated through the refrigerant circulation passage sequentially. it can.

  As described above, it is possible to provide a fuel cell system capable of efficiently performing uniform temperature distribution control of a fuel cell having an operating temperature of 300 ° C. or higher.

In the present invention (Claim 1), the inorganic refrigerant is an inorganic refrigerant, for example, a mixture of potassium nitrate (KNO ₃ ), sodium nitrite (NaNO ₂ ), and sodium nitrate (NaNO ₃ ). There is something that consists of. The mixing ratio can be, for example, 53% by weight of potassium nitrate (KNO ₃ ), 40% by weight of sodium nitrite (NaNO ₂ ), and 7% by weight of sodium nitrate (NaNO ₃ ). The inorganic refrigerant having this composition has a melting point of about 142 ° C.

  In addition, the fuel cell includes an anode flow path to which the hydrogen-containing fuel gas is supplied, a cathode flow path to which an oxygen-containing gas containing oxygen is supplied, and between the cathode flow path and the anode flow path. A hydrogen separation metal layer for allowing hydrogen in the hydrogen-containing fuel gas supplied to the anode channel to pass therethrough, and the hydrogen separation metal layer. It is preferable to laminate a proton conductor layer made of ceramics for allowing the hydrogen that has permeated to reach the cathode flow path in the form of hydrogen protons.

In this case, the fuel cell can be operated at a high temperature of, for example, 400 to 600 ° C or 400 to 500 ° C.
That is, the fuel cell includes an electrolyte body formed by laminating the hydrogen separation metal layer and the proton conductor layer, and the proton conductor layer made of ceramic can be used without being impregnated with moisture. Therefore, it can be operated in a high temperature state as described above.

Therefore, when reforming hydrocarbons or the like using a reformer to produce the hydrogen-containing fuel gas, the fuel cell can be used without significantly cooling the high-temperature hydrogen-containing fuel gas of, for example, 400 ° C. or higher. Can be supplied.
And by applying this invention to this fuel cell system, uniform temperature control of a fuel cell can be performed efficiently and the effect of this invention can fully be exhibited.

The inorganic refrigerant is preferably an inorganic refrigerant that is in a liquid state in the operating temperature range of the fuel cell.
In this case, for example, the cooling medium can be kept in a liquid state in the operating temperature region of the hydrogen separation membrane type fuel cell of 300 to 600 ° C., 400 to 600 ° C., or 400 to 500 ° C. The temperature distribution control of the fuel cell can be performed efficiently.

The inorganic refrigerant preferably contains at least one of potassium nitrate, sodium nitrite, and sodium nitrate.
In this case, a cooling medium that can be maintained in a liquid state without being deteriorated even at a high temperature of 300 ° C. or higher can be easily obtained.

In addition, it is preferable that heat exchange means for exchanging heat with the cooling medium is provided in at least a part of the refrigerant circulation channel or a portion communicating with the refrigerant circulation channel. ).
In this case, the temperature control of the cooling medium can be performed, the circulation of the cooling medium can be made smooth, and the cooling efficiency of the fuel cell can be improved.

That is, the cooling medium made of an inorganic refrigerant has a property of solidifying when the temperature is lowered to room temperature, for example. Therefore, in order to ensure smooth circulation of the cooling medium, it is necessary to prevent the cooling medium from lowering its temperature and prevent solidification, or to melt and solidify the solidified cooling medium.
In particular, when the system is stopped, the cooling medium may be solidified due to a decrease in temperature, and when the system is started, it is necessary to supply the heat of fusion to the solidified cooling medium to liquefy it to ensure circulation of the cooling medium. .
On the other hand, during the steady operation of the system, it is also necessary to improve the temperature controllability by removing the amount of heat received by the cooling medium from the fuel cell.

Therefore, heat exchange means for performing heat exchange with the cooling medium as described above is provided. Thereby, solidification prevention of a cooling medium, melting | dissolving, or heat removal can be performed efficiently, and the cooling efficiency can be improved while ensuring the smooth distribution | circulation of a cooling medium.
In addition, the circulation amount of the cooling medium can be reduced by improving the cooling efficiency accompanying the smooth removal of the heat amount of the cooling medium. Thereby, the temperature rise of a low-temperature cooling medium and the melting | dissolving of the solidified cooling medium can be performed in a short time.

Moreover, it is preferable that the said heat exchange means is comprised so that solidification of the said cooling medium can be prevented or the solidified said cooling medium can be fuse | melted (Claim 6).
In this case, as described above, the cooling medium can be reliably circulated smoothly in the liquid state.

The heat exchanging means preferably exchanges heat with the cooling medium using a gas or liquid heat exchanging fluid.
In this case, the temperature of the cooling medium can be easily adjusted.
In some cases, the system efficiency of the fuel cell system can be improved by effectively utilizing the heat exchange fluid that has exchanged heat with the cooling medium to balance the heat in the system.

In addition, the heat exchange means may include a heat exchange flow path for circulating the heat exchange fluid in parallel with the refrigerant circulation flow path (Claim 8).
In this case, the configuration of the fuel cell system can be simplified and sufficient heat exchange efficiency can be ensured.
The heat exchange means can be realized, for example, by configuring a double pipe in which the refrigerant circulation channel is arranged on the inner side and the heat exchange channel is arranged on the outer side, and vice versa. It can also be realized. In addition, the heat exchange means can be configured by a laminated tube in which a plurality of refrigerant circulation channels and a plurality of heat exchange channels are alternately laminated.
The heat exchange channel may be formed over the entire length of the refrigerant circulation channel or may be formed in part.

Further, the heat exchange means is the upper Northern link, may be each other configured to perform heat exchange between the cooling medium and the heat exchange fluid (claim 9).
In this case, heat exchange can be performed in a concentrated manner with the cooling medium collected in the tank, so that the heat exchange efficiency can be improved.
Moreover, since the cooling medium collected in the tank has a small surface area, it is difficult to be cooled and solidification is suppressed. Therefore, for example, by collecting the cooling medium in the tank when the system is stopped, solidification of the cooling medium can be suppressed.
Further, during steady operation of the system, the cooling medium can be sequentially fed into the tank and the temperature can be intensively adjusted in the tank, and the temperature-adjusted cooling medium can be sequentially circulated through the refrigerant circulation passage.

The heat exchanging means includes a heat exchanging unit that causes the cooling medium and the heat exchanging fluid to circulate inside to exchange heat between the cooling medium and the heat exchanging fluid. (Claim 10).
In this case, in the heat exchange unit, the cooling medium and the heat exchange fluid can be concentrated to exchange heat, so that the heat exchange efficiency can be improved.
Further, heat exchange between the cooling medium and the heat exchange fluid can be performed even during steady operation of the fuel cell system.

Further, as the heat exchanging fluid, a fluid whose temperature is adjusted by a heat exchanging means different from the heat exchanging means can be used.
In this case, it is possible to sufficiently control the temperature of the cooling medium.
The temperature of the heat exchange fluid can be adjusted, for example, by exchanging heat with external air using a radiator such as a radiator.
Further, by using a fluid whose temperature can be easily adjusted as the heat exchange fluid, the temperature of the cooling medium can be adjusted in detail.

In addition, combustion gas generated by combustion can be used as the heat exchange fluid.
In this case, it is possible to prevent the cooling medium from being lowered in temperature and prevent solidification, and to melt and liquefy the solidified cooling medium. Further, the combustion gas generated by combustion can be used as the heat exchange fluid and can be supplied to each element of the fuel cell system such as a fuel cell. As a result, by efficiently recovering the heat of the high temperature part of the fuel cell system and effectively using it in other elements inside the system, heat loss to the outside of the system can be reduced, and system efficiency can be improved. it can.

In addition, the fuel cell includes an anode flow path to which the hydrogen-containing fuel gas is supplied, a cathode flow path to which an oxygen-containing gas containing oxygen is supplied, and between the cathode flow path and the anode flow path. The oxygen-containing gas before being supplied to the cathode channel can be used as the heat exchange fluid.
In this case, heat of the cooling medium can be exchanged with the heat exchange fluid, and an increase in the temperature of the cooling medium during steady operation of the fuel cell can be prevented. Thereby, temperature control of the fuel cell can be performed.
The oxygen-containing gas rises in temperature upon receiving heat from heat exchange with the cooling medium. Therefore, since the oxygen-containing gas is supplied to the cathode flow path of the fuel cell at a high temperature, it is possible to prevent a temperature drop at the inlet of the cathode flow path of the fuel cell and to prevent uneven temperature distribution. it can.

The fuel cell system further includes a reformer having a reforming reaction channel that generates hydrogen-containing fuel gas from the reforming fuel, and a heating channel that heats the reforming reaction channel. The reformer combustion gas before being supplied to the heating flow path can be used as the heat exchange fluid.
In this case, the heat of the cooling medium can be released to the heat exchange fluid, and an increase in the temperature of the cooling medium during steady operation of the fuel cell can be prevented. Thereby, temperature control of the fuel cell can be performed.
Further, the temperature of the reformer combustion gas rises by receiving heat from heat exchange with the cooling medium. Therefore, the reformer combustion gas is supplied to the heating passage of the reformer at a high temperature. Therefore, the amount of heat supplied to the reformer combustion gas to be supplied from outside the system in the reformer can be suppressed.

The fuel cell system includes a reforming reaction channel that generates hydrogen-containing fuel gas containing hydrogen from the reforming fuel, and a reforming channel that has a heating channel for heating the reforming reaction channel. The reformer combustion off-gas discharged from the heating flow path can be used as the heat exchange fluid.
In this case, the heat quantity of the reformer combustion off-gas can be used to prevent the cooling medium from lowering its temperature and prevent solidification, or to melt and liquefy the solidified cooling medium.
Further, the system efficiency can be improved by collecting the heat of the reformer combustion off-gas as it is for supplying heat to the cooling medium without directly releasing it to the outside of the system.

The heat exchange means may include a heater that directly heats the cooling medium.
In this case, the cooling medium can be directly heated to prevent a decrease in temperature of the cooling medium to prevent solidification or to melt and liquefy the solidified cooling medium.

The heat exchanging means may include an electric heater.
In this case, the cooling medium can be heated rapidly. Further, since the electric heater is easy to control the heating, the temperature control of the cooling medium can be performed in detail.

The heat exchanging means may include a catalytic combustion heater (claim 18).
Also in this case, the cooling medium can be rapidly heated. Further, the temperature control of the cooling medium can be performed in detail.

Further, the fuel cell system is provided with two refrigerant circulation passages, and the inorganic refrigerant is circulated through one of the refrigerant circulation passages, and the gas refrigerant is circulated through the other refrigerant circulation passage. (Claim 19).
In this case, since the fuel cell can be supplementarily cooled by the gas refrigerant, the cooling efficiency can be improved. As a result, the flow rate of the cooling medium can be reduced, and as a result, the temperature of the cooling medium can be increased and the solidified cooling medium can be easily melted.
Further, the inorganic refrigerant is preferably solidified when the temperature is lowered to room temperature.
In this case, smooth circulation of the cooling medium can be ensured.

( Reference Example 1 )
A fuel cell system according to a reference example of the present invention will be described with reference to FIGS.
The fuel cell system 1 of this example includes a fuel cell 3 that generates power using a hydrogen-containing fuel gas 51 containing hydrogen.
The fuel cell system 1 has a refrigerant circulation passage 4 that circulates a cooling medium 41 for cooling the fuel cell 3 in a liquid state.
The cooling medium 41 is an inorganic refrigerant.

As the inorganic refrigerant, a refrigerant composed of a mixture of potassium nitrate (KNO ₃ ), sodium nitrite (NaNO ₂ ), and sodium nitrate (NaNO ₃ ) is used. The mixing ratio can be 53 wt% potassium nitrate (KNO ₃ ), 40 wt% sodium nitrite (NaNO ₂ ), and 7 wt% sodium nitrate (NaNO ₃ ). The inorganic refrigerant having this composition has a melting point of about 142 ° C.

  In this example, potassium nitrate, sodium nitrite, and sodium nitrate are used as the inorganic refrigerant. However, the inorganic refrigerant that can be used for the cooling medium 41 is not limited thereto, and the operation of the hydrogen separation membrane fuel cell is not limited thereto. Any inorganic material that is in a liquid state at a temperature (for example, 300 to 600 ° C.) may be used.

  As shown in FIGS. 1 and 2, the fuel cell 3 includes an anode channel 32 to which the hydrogen-containing fuel gas 51 is supplied, a cathode channel 33 to which an oxygen-containing gas 52 containing oxygen is provided, An electrolyte body 31 is provided between the cathode channel 33 and the anode channel 32. The electrolyte body 31 includes a hydrogen separation metal layer 311 for allowing hydrogen in the hydrogen-containing fuel gas 51 supplied to the anode flow path 32 to pass through, and hydrogen that has passed through the hydrogen separation metal layer 311 in a hydrogen proton state. Then, a proton conductor layer 312 made of ceramics for passing through and reaching the cathode channel 33 is laminated.

The hydrogen separation metal layer 311 is made of a laminated metal of palladium (Pd) and vanadium (V). Note that the hydrogen separation metal layer 311 may be made of only palladium or an alloy containing the palladium. Further, the hydrogen separation metal layer 311 has a hydrogen permeation performance (hydrogen separation performance) exceeding 10 A / cm ² in terms of current density under an anode gas supply condition of 3 atm. Thus, the conductive resistance of the hydrogen separation metal layer 311 is made small enough to be ignored.
The proton conductor layer 312 is made of a perovskite oxide as a ceramic. The conductive resistance of the proton conductor layer 312 is reduced until it is about the same as the conductive resistance of the solid polymer electrolyte membrane. As the perovskite-type oxide, such as those of BaCeO ₃ system, there is a SrCeO ₃ system.

  As shown in FIG. 2, the electrolyte body 31 includes an anode electrode 321 (anode) formed on the surface of the proton conductor layer 312 on the anode flow channel 32 side, and the cathode of the proton conductor layer 312. It has a cathode electrode 331 (cathode) formed on the surface on the channel 33 side. A battery output line 36 for taking out electric power from the fuel cell 3 is connected between the anode electrode 321 and the cathode electrode 331.

Further, the anode electrode 321 in the proton conductor layer 312 is made of palladium constituting the hydrogen separation metal layer 311. The cathode electrode 331 in the proton conductor layer 312 is composed of a Pt-based electrode catalyst. The anode electrode 321 can also be composed of a Pt-based electrode catalyst.
The operating temperature of the fuel cell 3 is 400 to 600 ° C., preferably 400 to 500 ° C. In order to keep the temperature of the fuel cell 3 in this temperature range, as shown in FIG. 4 is distributed.

As shown in FIG. 1, the fuel cell system 1 includes a reforming reaction channel 21 that generates a hydrogen-containing fuel gas 51 from the reforming fuel 50, and heating for heating the reforming reaction channel 21. A reformer 2 having a flow path 22 is provided.
Further, the reforming reaction channel 21 is heated by supplying the reformer combustion gas 54 and burning it in the heating channel 22.
As the reforming fuel 50, a hydrocarbon fuel is used. As the reformer combustion gas 54, a hydrocarbon fuel as a reforming raw material is used. Alternatively, or together with this, the anode off-gas 511 containing unused H ₂ , heated CO, CH _4, etc. can be supplied to the heating channel 22 and burned.

The refrigerant circulation channel 4 is provided with heat exchange means 6 for exchanging heat with the cooling medium 41. The heat exchange means 6 performs heat exchange with the cooling medium 41 using a gas or liquid heat exchange fluid 61.
The heat exchange fluid 61 circulates through the heat exchange channel 60 disposed in parallel with the refrigerant circulation channel 4.

As shown in FIG. 3, the heat exchanging means 6 can be realized by constituting a double pipe in which the refrigerant circulation channel 4 is arranged outside and the heat exchange channel 60 is arranged inside. Moreover, it is also realizable by the reverse structure.
As shown in FIG. 4, the heat exchanging means 6 can also be constituted by a laminated tube in which a plurality of refrigerant circulation channels 4 and a plurality of heat exchange channels 60 are alternately laminated.
3 and 4 show a state in which the cooling medium 41 in the refrigerant circulation passage 4 is solidified.

The heat exchange flow path 60 is formed over the entire length of the refrigerant circulation flow path 4 as shown in FIG. However, the heat exchange channel 60 may be formed in a part of the refrigerant circulation channel 4.
The fluid used as the heat exchange fluid 61 will be specifically described in Reference Examples 2 to 6 below.

  As shown in FIG. 1, a fuel gas heat exchanger 11 is disposed between the reformer 2 and the fuel cell 3, and the hydrogen-containing fuel gas 51 generated in the reformer 2 The temperature is adjusted and sent to the fuel cell 3. In the fuel gas heat exchanger 11, the temperature of the hydrogen-containing fuel gas 51 is adjusted by exchanging heat with the cathode off gas 521 discharged from the cathode flow path 33 of the fuel cell 3.

  As shown in FIG. 1, the cathode offgas 521 that has passed through the fuel gas heat exchanger 11 and is in a high temperature state is guided to the reforming reaction channel 21 of the reformer 2. As a result, the oxygen remaining in the cathode offgas 521 that has not been used for the reaction in the fuel cell 3 and the heat transported by gas sensible heat can be effectively utilized in the reforming reaction channel 21.

Further, the high temperature anode off gas 511 discharged from the anode flow path 32 of the fuel cell 3 is guided to the heating flow path 22 of the reformer 2. Thus, the residual hydrogen in the anode off-gas 511 that has not permeated the hydrogen separation metal layer 311 in the electrolyte body 31 of the fuel cell 3 and the heat transported by gas sensible heat can be effectively used in the heating flow path 22. it can.
Further, the reformer combustion off-gas 541 discharged from the heating flow path 22 of the reformer 2 is discharged outside the fuel cell system 1.
FIG. 1 is a schematic diagram of the fuel cell system 1, and various pumps, various valves, various valves, and other elements provided in the refrigerant circulation flow path 4 and the heat exchange flow path 60 are described. Is omitted.

Next, the function and effect of this example will be described.
In the fuel cell system 1, an inorganic refrigerant is used as the cooling medium 41 for cooling the fuel cell 3. Since the inorganic refrigerant is composed of an inorganic substance, it has excellent thermal stability and does not deteriorate even at a high temperature of 300 ° C. or higher.
Therefore, the inorganic refrigerant sufficiently functions as a cooling medium 41 for controlling the temperature of the fuel cell 3 in which the operating temperature is a predetermined region of 300 ° C. or higher (400 to 600 ° C. in this example). Can do.

The inorganic refrigerant can be kept in a liquid state at 300 ° C. or higher. That is, the melting point of the inorganic refrigerant of this example is about 142 ° C., and is in a liquid state at 300 ° C. or higher.
Therefore, since the cooling medium 41 (inorganic refrigerant) can be circulated through the refrigerant circulation passage 4 with a large heat capacity, the efficiency of heat exchange with the fuel cell 3 can be increased. And since the temperature rise of the cooling medium 41 during passing through the fuel cell 3 can be suppressed, the temperature distribution inside the fuel cell 3 can be made uniform.

The fuel cell 3 is a fuel cell having an electrolyte body 31 formed by laminating the hydrogen separation metal layer 311 and the proton conductor layer 312 as shown in FIG.
Therefore, the fuel cell 3 can be operated at a high temperature of 400 to 600 ° C. or 400 to 500 ° C. That is, the fuel cell 3 includes an electrolyte body 311 in which the hydrogen separation metal layer 311 and the proton conductor layer 312 are laminated, and the proton conductor layer 312 made of ceramic is not impregnated with moisture. Therefore, it can be operated at a high temperature as described above.

Therefore, the fuel cell is produced without significantly cooling the hydrogen-containing fuel gas 51 having a high temperature of 400 to 600 ° C. generated by reforming the hydrocarbon (reforming fuel 50) using the reformer 2. 3 can be supplied.
Then, by applying the present invention to such a fuel cell system 1, the temperature control of the fuel cell 3 efficiently performed, Ru can be made uniform internal temperature distribution.

  In particular, in such a fuel cell 3, if a temperature distribution is generated inside, it may cause a decrease in durability due to the generation of thermal stress. However, by making the temperature distribution uniform as described above, 3 durability can be improved. Also, by realizing this uniform temperature field, problems such as hydrogen embrittlement and metal diffusion in the fuel cell 3 can be prevented.

Further, as shown in FIG. 1, since the heat exchange means 6 is provided in the refrigerant circulation channel 4, the temperature of the cooling medium 41 can be controlled, and the circulation of the cooling medium 41 is made smooth. At the same time, the cooling efficiency of the fuel cell 3 can be improved.
That is, since the cooling medium 41 made of an inorganic refrigerant has a melting point of about 142 ° C., for example, it has a property of solidifying when the temperature falls to room temperature. Therefore, in order to ensure a smooth distribution of the cooling medium 41, the temperature of the cooling medium 41 is prevented from lowering to prevent solidification, or the solidified cooling medium 41 (see FIGS. 3 and 4) is melted and liquefied. There is a need to.

In particular, when the system is stopped, the cooling medium 41 may decrease in temperature and solidify. When the system is started, the solidified cooling medium 41 (see FIGS. 3 and 4) is supplied with heat of fusion to liquefy, It is necessary to ensure the circulation of the cooling medium 41.
On the other hand, during the steady operation of the system, it is necessary to improve the temperature controllability by removing the amount of heat received from the fuel cell 3 by the cooling medium 41.

Therefore, the heat exchange means 6 for performing heat exchange with the cooling medium 41 as described above is provided. Thereby, solidification prevention of the cooling medium 41, melting | dissolving, or heat removal can be performed efficiently, smooth circulation of the cooling medium 41 can be ensured, and cooling efficiency can be improved.
Further, the circulation amount of the cooling medium 41 can be reduced by improving the cooling efficiency accompanying the smooth removal of the heat quantity of the cooling medium 41. Thereby, the temperature rise of the low-temperature cooling medium 41 and the melting of the solidified cooling medium 41 (see FIGS. 3 and 4) can be performed in a short time.

Moreover, since the heat exchanging means 6 performs heat exchange with the cooling medium 41 using a gas or liquid heat exchanging fluid 61, the temperature of the cooling medium 41 can be easily adjusted.
In some cases, the system efficiency of the fuel cell system 1 can be improved by effectively using the heat exchange fluid 61 that has exchanged heat with the cooling medium 41 to balance the heat in the system. it can.

Further, since the heat exchanging means 6 has a heat exchanging channel 60 for circulating the heat exchanging fluid 61 in parallel with the refrigerant circulating channel 4, the configuration of the fuel cell system 1 is simplified. And sufficient heat exchange efficiency can be secured.
That is, by configuring the heat exchanging means 6 with a double tube as shown in FIG. 3 or a laminated tube as shown in FIG. 4, the configuration of the fuel cell system 1 is simplified and the heat exchange efficiency is improved. Can be improved.
Moreover, since the said heat exchange flow path 60 is formed over the full length of the said refrigerant | coolant circulation flow path 4, sufficient heat transfer area can be ensured and sufficient heat exchange efficiency can be acquired. Moreover, even if the cooling medium 41 solidifies in any part in the path | route of the refrigerant | coolant circulation flow path 4, this can be melt | dissolved easily and liquefied.

  As described above, it is possible to provide a fuel cell system capable of efficiently performing uniform temperature distribution control of a fuel cell having an operating temperature of 300 ° C. or higher.

( Reference Example 2 )
This example is an example of the fuel cell system 1 using an oxygen-containing gas 52 before being supplied to the cathode flow path 33 of the fuel cell 3 as the heat exchange fluid 61 as shown in FIG.
That is, the oxygen-containing gas 52 is circulated through the heat exchange channel 60 as the heat exchange fluid 61. The oxygen-containing gas 52 is supplied to the cathode flow path 33 of the fuel cell 3 after performing heat exchange with the cooling medium 41.
Others are the same as in Reference Example 1 .

In this case, the heat of the cooling medium 41 can be released to the heat exchanging fluid 61, and the temperature rise of the cooling medium 41 during steady operation of the fuel cell 3 can be prevented. Thereby, the temperature control of the fuel cell 3 can be performed.
The oxygen-containing gas 52 rises in temperature by receiving heat from heat exchange with the cooling medium 41. Therefore, since the oxygen-containing gas 52 is supplied to the cathode flow path 33 of the fuel cell 3 in a high temperature state, the temperature distribution in the fuel cell 3 can be prevented from being uneven.
In addition, the same effects as those of Reference Example 1 are obtained.

( Reference Example 3 )
This example is an example of the fuel cell system 1 using the reformer combustion gas 54 before being supplied to the heating flow path 22 of the reformer 2 as the heat exchange fluid 61 as shown in FIG.
That is, the reformer combustion gas 54 is circulated as a heat exchange fluid 61 through the heat exchange flow path 60. The reformer combustion gas 54 is supplied to the heating flow path 22 of the reformer 2 after performing heat exchange with the cooling medium 41.
Others are the same as in Reference Example 1 .

In this case, the heat of the cooling medium 41 can be released to the heat exchanging fluid 61, and the temperature rise of the cooling medium 41 during steady operation of the fuel cell 3 can be prevented. Thereby, the temperature control of the fuel cell 3 can be performed.
Further, the reformer combustion gas 54 receives a heat amount by heat exchange with the cooling medium 41 and rises in temperature. Therefore, the reformer combustion gas 54 is supplied to the heating flow path 22 of the reformer 2 at a high temperature. Therefore, the amount of heat supplied to the reformer combustion gas 54 to be supplied from the outside of the system in the reformer 2 can be suppressed by effectively using the heat transported by the gas sensible heat.
Others are the same as in Reference Example 1 .

( Reference Example 4 )
This example is an example of the fuel cell system 1 using a fluid whose temperature is adjusted by a heat exchanging means 12 different from the heat exchanging means 6 as the heat exchanging fluid 61 as shown in FIG.
The temperature of the heat exchanging fluid 61 can be adjusted by exchanging heat with external air using a radiator (heat exchanging means 12) such as a radiator.
Others are the same as in Reference Example 1 .

In this case, the temperature control of the cooling medium 41 can be sufficiently performed.
Further, by using a fluid whose temperature can be easily adjusted as the heat exchanging fluid 61, the temperature of the cooling medium 41 can be adjusted in detail.
In addition, the same effects as those of Reference Example 1 are obtained.

( Reference Example 5 )
This example is an example of the fuel cell system 1 using the reformer combustion off-gas 541 discharged from the heating flow path 22 of the reformer 2 as the heat exchange fluid 61 as shown in FIG.
That is, the reformer combustion off-gas 541 is circulated through the heat exchange channel 60 as the heat exchange fluid 61. The reformer combustion off-gas 541 is discharged outside the fuel cell system 1 after performing heat exchange with the cooling medium 41.
Others are the same as in Reference Example 1 .

In this case, the amount of heat of the reformer combustion off-gas 541 can be used to prevent the cooling medium 41 from lowering in temperature and prevent solidification, or to melt and liquefy the solidified cooling medium 41.
In addition, the system efficiency can be improved by collecting the heat of the reformer combustion off-gas 541 as it is for supplying heat to the cooling medium 41 without releasing it to the outside of the system as it is.
In addition, the same effects as those of Reference Example 1 are obtained.

( Reference Example 6 )
This example is an example of the fuel cell system 1 using the combustion gas 55 generated by combustion as the heat exchange fluid 61 as shown in FIGS.
The combustion gas 55 can be generated by burning an anode off gas containing unused H ₂ , combustible CO, and CH ₄ .

  For example, as shown in FIG. 10, the combustion gas 55 at the time of system startup is sequentially passed through the reforming reaction channel 21 of the reformer 2, the fuel gas heat exchanger 11, and the anode channel 32 of the fuel cell 3. After that, the heat exchange fluid 61 may be introduced into the heat exchange channel 60. The combustion gas 55 after heat exchange with the cooling medium 41 can be introduced into the heating flow path 22 of the reformer 2.

  Further, as shown in FIG. 11, after the combustion gas 55 is sequentially passed through the reforming reaction channel 21 of the reformer 2, the heat exchanger 11 for fuel gas, and the anode channel 32 of the fuel cell 3, Furthermore, the heating channel 22 of the reformer 2 may be passed, and then introduced into the heat exchange channel 60 as the heat exchange fluid 61. Then, the combustion gas 55 after heat exchange with the cooling medium 41 is discharged outside the fuel cell system 1.

Further, as shown in FIG. 12, after the combustion gas 55 has passed through the reforming reaction channel 21 of the reformer 2, the fuel gas 55 is passed through the heat exchange channel 60 instead of the fuel gas heat exchanger 11. You may comprise so that it may introduce into the anode flow path 32 of the battery 3. FIG. Thereafter, the combustion gas 55 is introduced into the heating flow path 22 of the reformer 2.
Others are the same as in Reference Example 1 .

In the case of this example, the cooling medium 41 can be prevented from being lowered in temperature and solidified, and the solidified cooling medium 41 (see FIGS. 3 and 4) can be melted and liquefied.
Further, as described above, the combustion gas 55 generated by combustion can be used as the heat exchange fluid 61 and can be supplied to each element of the fuel cell system 1 such as the fuel cell 3 and the reformer 2. As a result, the heat of the high temperature part of the fuel cell system 1 can be efficiently recovered and effectively used in other elements inside the system, so that the heat dissipation loss to the outside of the system can be reduced and the system efficiency is improved. Can be achieved.
In addition, the same effects as those of Reference Example 1 are obtained.

(Example 1 )
This example is an embodiment according to the present invention, and as shown in FIGS. 13 to 20, the cooling medium 41 and the heat exchange fluid in the tank 14 that is in communication with the refrigerant circulation passage 4 and stores the cooling medium 41. This is an example of the fuel cell system 1 in which the heat exchanging means 6 is configured to exchange heat with 61.
In the fuel cell system 1 of this example, when the system is stopped, the cooling medium 41 is all collected in the tank 14 by suction by a pump, gas pressure feeding to the refrigerant circulation passage 4, or the like. Further, when the system is started, the cooling medium 41 in the tank 14 is sent into the refrigerant circulation passage 4 using a pump, a compressor, an ejector or the like.

Further, at the time of steady operation of the system, the valve between the tank 14 and the refrigerant circulation channel 4 may be closed to circulate the cooling medium 41 in the refrigerant circulation channel 4. It is also possible to circulate the refrigerant and send it to the refrigerant circulation passage 4 while adjusting the temperature of the cooling medium 41 in the tank 14.
Then, heat exchange with the cooling medium 41 is performed by causing the heat exchange fluid 61 to flow through the flow path disposed in the tank 14. This flow path may be arranged around the tank 14.

Heat exchange between the cooling medium 41 and the heat exchange fluid 61 in the tank 14 can be performed by various methods as described below.
For example, as shown in FIG. 13, the oxygen-containing gas 52 before being supplied to the cathode flow path 33 of the fuel cell 3 can be used as the heat exchange fluid 61. In this case, the oxygen-containing gas 52 is introduced into the flow path in the tank 14, heat exchange with the cooling medium 41 is performed, and then supplied to the cathode flow path 33.
In this configuration, during the steady operation of the system, the cooling medium 41 is sequentially fed into the tank 14 and the temperature is intensively adjusted in the tank 14, and the temperature-adjusted cooling medium 41 is sequentially circulated through the refrigerant circulation passage 4. Let

Further, as shown in FIG. 14, the reformer combustion gas 54 before being supplied to the heating flow path 22 of the reformer 2 can be used as the heat exchange fluid 61. That is, the reformer combustion gas 54 is circulated as a heat exchange fluid 61 through the flow path in the tank 14. The reformer combustion gas 54 is supplied to the heating flow path 22 of the reformer 2 after performing heat exchange with the cooling medium 41.
Also in this configuration, during the steady operation of the system, the cooling medium 41 is circulated through the refrigerant circulation passage 4 sequentially while the temperature is intensively adjusted in the tank 14.

Further, as shown in FIG. 15, a fluid whose temperature is adjusted by a heat exchanging means 12 different from the heat exchanging means 6 can be used as the heat exchanging fluid 61. That is, a fluid whose temperature is adjusted by heat exchange with external air by a radiator such as a radiator is sent to the flow path in the tank 14.
Also in this configuration, during the steady operation of the system, the cooling medium 41 is circulated through the refrigerant circulation passage 4 sequentially while the temperature is intensively adjusted in the tank 14.

Further, as shown in FIG. 16, the reformer combustion off-gas 541 discharged from the heating flow path 22 of the reformer 2 can be used as the heat exchange fluid 61. That is, the reformer combustion off-gas 541 is circulated as the heat exchange fluid 61 through the flow path in the tank 14. The reformer combustion off-gas 541 is discharged to the outside of the fuel cell system 1 after performing heat exchange with the cooling medium 41 in the tank 14.
In this configuration, when the system is stopped, all the cooling medium 41 is collected in the tank 14, and when the system is started, the temperature of the cooling medium 41 is concentrated in the tank 14 and sent to the refrigerant circulation passage 4.

Moreover, as shown in FIGS. 17-20, the combustion gas 55 produced | generated by combustion can also be used as the fluid 61 for heat exchange. That is, it is the structure according to the reference example 6 (FIGS. 9 to 12).
Also in this configuration, when the system is stopped, all the cooling medium 41 is collected in the tank 14, and when the system is started, the cooling medium 41 is intensively heated in the tank 14 and sent to the refrigerant circulation passage 4.

  Specifically, for example, as shown in FIG. 18, the combustion gas 55 at the time of starting the system is changed into a reforming reaction channel 21 of the reformer 2, a fuel gas heat exchanger 11, and an anode channel of the fuel cell 3. Alternatively, the heat exchange fluid 61 may be introduced into the flow path in the tank 14 after sequentially passing through 32. Then, the combustion gas 55 after heat exchange with the cooling medium 41 is discharged outside the fuel cell system 1.

  Further, as shown in FIG. 19, after the combustion gas 55 is sequentially passed through the reforming reaction channel 21 of the reformer 2, the heat exchanger 11 for fuel gas, and the anode channel 32 of the fuel cell 3, Further, the heating passage 22 of the reformer 2 may be passed, and then introduced into the passage in the tank 14 as the heat exchange fluid 61.

Further, as shown in FIG. 20, after the combustion gas 55 has passed through the reforming reaction channel 21 of the reformer 2, instead of passing through the fuel gas heat exchanger 11, through the channel in the tank 14, You may comprise so that it may introduce into the anode flow path 32 of the fuel cell 3. FIG. Thereafter, the combustion gas 55 is introduced into the heating flow path 22 of the reformer 2.
Others are the same as in Reference Example 1 .

In the case of the present embodiment , heat exchange can be performed in a concentrated manner in a state where the cooling medium 41 is collected in the tank 14, so that the heat exchange efficiency can be improved.
Moreover, since the cooling medium 41 collected in the tank 14 has a small surface area, it is difficult to be cooled and solidification is suppressed. Therefore, for example, by collecting the cooling medium 41 in the tank 14 when the system is stopped, the solidification of the cooling medium 41 can be suppressed.
In addition, the same effects as those of Reference Example 1 are obtained. In addition, the fuel cell system 1 having various configurations shown in the present example has the same functions and effects as those of Reference Examples 2 to 6 corresponding to the respective configurations.

( Reference Example 7 )
In this example, as shown in FIG. 21 to FIG. 28, the heat exchanging unit 62 that causes the cooling medium 41 and the heat exchanging fluid 61 to circulate inside and exchanges heat between the cooling medium 41 and the heat exchanging fluid 61. This is an example of the fuel cell system 1 constituting the heat exchanging means 6.
That is, the heat exchange unit 62 is incorporated into a part of the refrigerant circulation flow path 4.
Examples of the heat exchange unit 62 include a plate fin type heat exchanger and a fin and tube type heat exchanger.

The heat exchange between the cooling medium 41 and the heat exchange fluid 61 in the heat exchange unit 62 can be performed by various methods as described below.
For example, as shown in FIG. 21, the oxygen-containing gas 52 before being supplied to the cathode flow path 33 of the fuel cell 3 can be used as the heat exchange fluid 61. In this case, the oxygen-containing gas 52 is introduced into the heat exchange unit 62, and after heat exchange with the cooling medium 41, the oxygen-containing gas 52 is supplied to the cathode channel 33.

  Further, as shown in FIG. 22, the reformer combustion gas 54 before being supplied to the heating flow path 22 of the reformer 2 can be used as the heat exchange fluid 61. That is, the reformer combustion gas 54 is circulated through the heat exchange unit 62 as the heat exchange fluid 61. The reformer combustion gas 54 is supplied to the heating flow path 22 of the reformer 2 after performing heat exchange with the cooling medium 41.

  Further, as shown in FIG. 23, a fluid whose temperature is adjusted by the heat exchanging means 12 different from the heat exchanging means 6 can be used as the heat exchanging fluid 61. That is, a fluid whose temperature is adjusted by heat exchange with external air by a radiator such as a radiator is sent to the heat exchange unit 62.

  Further, as shown in FIG. 24, the reformer combustion off-gas 541 discharged from the heating flow path 22 of the reformer 2 can be used as the heat exchange fluid 61. That is, the reformer combustion off-gas 541 is circulated through the heat exchange unit 62 as the heat exchange fluid 61. The reformer combustion off-gas 541 is discharged to the outside of the fuel cell system 1 after performing heat exchange with the cooling medium 41 in the tank 14.

Further, as shown in FIGS. 25 to 28, the combustion gas 55 produced by combustion can be used as the heat exchange fluid 61. That is, it is the structure according to the reference example 6 (FIGS. 9 to 12).
Specifically, for example, as shown in FIG. 26, the combustion gas 55 at the time of system startup is changed into a reforming reaction channel 21 of the reformer 2, a fuel gas heat exchanger 11, and an anode channel of the fuel cell 3. Alternatively, the heat exchange unit 61 may be configured to introduce the heat exchange fluid 61 into the heat exchange unit 62 after sequentially passing through the heat exchanger 32. The combustion gas 55 after heat exchange with the cooling medium 41 can be further introduced into the heating flow path 22 of the reformer 2.

  Further, as shown in FIG. 27, after the combustion gas 55 is sequentially passed through the reforming reaction channel 21 of the reformer 2, the heat exchanger 11 for fuel gas, and the anode channel 32 of the fuel cell 3, Further, the heating passage 22 of the reformer 2 may be passed, and then introduced into the heat exchange unit 62 as the heat exchange fluid 61.

Further, as shown in FIG. 28, after the combustion gas 55 has passed through the reforming reaction flow path 21 of the reformer 2, the fuel cell is passed through the heat exchange unit 62 instead of the fuel gas heat exchanger 11. It may be configured to be introduced into the three anode flow paths 32. Thereafter, the combustion gas 55 is introduced into the heating flow path 22 of the reformer 2.
Others are the same as in Reference Example 1 .

In the case of this example, in the heat exchanging unit 62, the cooling medium 41 and the heat exchanging fluid 61 can be concentrated to exchange heat, so that the heat exchanging efficiency can be improved.
In addition, heat exchange between the cooling medium 41 and the heat exchange fluid 61 can be performed even during steady operation of the fuel cell system 1.
In addition, the same effects as those of Reference Example 1 are obtained. In addition, the fuel cell system 1 having various configurations shown in the present example has the same functions and effects as those of Reference Examples 2 to 6 corresponding to the respective configurations.

( Reference Example 8 )
This example is an example of the fuel cell system 1 having a heater 63 that directly heats the cooling medium 41 as the heat exchange means 6 as shown in FIG.
As the heater 63, an electric heater or a catalytic combustion heater is used.
Moreover, when using an electric heater, it can arrange | position, for example by winding a sheath heater, a metal resistance type | mold film-like heater, etc. around the refrigerant | coolant circulation flow path 4. FIG.

When a catalytic combustion heater is used, for example, a Pt-based, Pd-based, or Ru-based catalyst is applied to the outer peripheral surface of the refrigerant circulation passage 4 and stored in vaporized hydrocarbon or buffer. By supplying hydrogen, the catalyst is combusted to generate heat.
Others are the same as in Reference Example 1 .

In the case of this example, the cooling medium 41 can be directly heated to prevent a decrease in temperature of the cooling medium 41 to prevent solidification, or to melt and liquefy the solidified cooling medium.
Moreover, the cooling medium 41 can be rapidly heated by using an electric heater or a catalytic combustion heater. Moreover, since heating control is easy, the temperature control of the cooling medium 41 can be performed in detail.
In addition, the same effects as those of Reference Example 1 are obtained.

(Example 2 )
In this example, as shown in FIG. 30 and FIG. 31, two refrigerant circulation channels 4a and 4b are provided. An inorganic refrigerant 41a is circulated in one refrigerant circulation channel 4a, and the other refrigerant circulation channel is provided. 4b shows an example of the fuel cell system 1 in which the gas refrigerant 41b is circulated.
Specifically, as shown in FIG. 30, the two refrigerant circulation channels 4 a and 4 b are passed through the fuel cell 3 and also through the heat exchange unit 42. The fuel cell system 1 is also provided with a tank 14, and is configured so that heat exchange between the inorganic refrigerant 41 a and the gas refrigerant 41 b can be performed in the tank 14. Thereby, the inorganic refrigerant 41a solidified in the tank 14 can be melted by the high-temperature gas refrigerant 41b.
As the gas refrigerant 41b, the anode off-gas 511 discharged from the anode channel 32 is used. In addition, although not shown, a cathode off gas discharged from the cathode flow path 33 may be used as the gas refrigerant 41b.

For reference, as shown in FIG. 31, the reformer combustion gas 54 before being supplied to the heating flow path 22 of the reformer 2 can be used as the gas refrigerant 41 b in the fuel cell 3. Thus, the reformer combustion gas 54 as the gas refrigerant 41b, which receives the amount of heat from the fuel cell 3, is cooled in the high temperature state while the fuel cell 3 is cooled by the gas refrigerant 41b. Two heating channels 22 can be supplied.
Others are the same as in Reference Example 1 .

In the case of this example, since the fuel cell 3 can be supplementarily cooled by the gas refrigerant 41b, the cooling capacity can be improved. As a result, the flow rate of the inorganic refrigerant 41a can be reduced, and as a result, the temperature of the inorganic refrigerant 41a is increased and the solidified inorganic refrigerant 41a (see FIGS. 3 and 4) is easily melted. Can do.
In addition, the same effects as those of Reference Example 1 are obtained.

The schematic diagram of the fuel cell system in the reference example 1. FIG. Explanatory drawing of the fuel cell in the reference example 1. FIG. Sectional drawing of the double pipe | tube as a heat exchange means in the reference example 1. FIG. Sectional drawing of the laminated pipe as a heat exchange means in the reference example 1. FIG. The schematic diagram of the fuel cell system in the reference example 2. FIG. The schematic diagram of the fuel cell system in the reference example 3. FIG. The schematic diagram of the fuel cell system in the reference example 4. FIG. The schematic diagram of the fuel cell system in the reference example 5. FIG. The schematic diagram of the 1st fuel cell system in the reference example 6. FIG. The schematic diagram of the 2nd fuel cell system in the reference example 6. FIG. The schematic diagram of the 3rd fuel cell system in the reference example 6. FIG. The schematic diagram of the 4th fuel cell system in reference example 6. FIG. 1 is a schematic diagram of a first fuel cell system in Embodiment 1. FIG. FIG. 3 is a schematic diagram of a second fuel cell system according to the first embodiment. FIG. 3 is a schematic diagram of a third fuel cell system in the first embodiment. 4 is a schematic diagram of a fourth fuel cell system in Embodiment 1. FIG. The schematic diagram of the 5th fuel cell system in Example 1. FIG. The schematic diagram of the 6th fuel cell system in Example 1. FIG. The schematic diagram of the 7th fuel cell system in Example 1. FIG. The schematic diagram of the 8th fuel cell system in Example 1. FIG. The schematic diagram of the 1st fuel cell system in the reference example 7. FIG. The schematic diagram of the 2nd fuel cell system in the reference example 7. FIG. The schematic diagram of the 3rd fuel cell system in the reference example 7. FIG. The schematic diagram of the 4th fuel cell system in reference example 7. FIG. FIG. 10 is a schematic diagram of a fifth fuel cell system in Reference Example 7 . The schematic diagram of the 6th fuel cell system in reference example 7. FIG. The schematic diagram of the 7th fuel cell system in the reference example 7. FIG. The schematic diagram of the 8th fuel cell system in the reference example 7. FIG. The schematic diagram of the fuel cell system in the reference example 8. FIG. FIG. 3 is a schematic diagram of a fuel cell system in Example 2 . The schematic diagram of the other fuel cell system shown in Example 2 for reference .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 14 Tank 2 Reformer 21 Reformation reaction flow path 22 Heating flow path 3 Fuel cell 31 Electrolyte body 311 Hydrogen separation metal layer 312 Proton conductor layer 32 Anode flow path 33 Cathode flow path 4 Refrigerant circulation flow path 41 Cooling medium 51 Hydrogen-containing fuel gas 6 Heat exchange means 60 Heat exchange flow path 61 Heat exchange fluid 62 Heat exchange unit

Claims (20)

In a fuel cell system including a fuel cell that generates power at an operating temperature of 300 ° C. or higher using a hydrogen-containing fuel gas containing hydrogen,
The fuel cell system has a refrigerant circulation channel for circulating a cooling medium for cooling the fuel cell in a liquid state,
Upper Symbol cooling medium is made using an inorganic refrigerant in the liquid state at 300 ° C. or higher,
And a tank that is in communication with the refrigerant circulation channel and includes a heat exchange means for exchanging heat with the inorganic refrigerant,
The tank collects the inorganic refrigerant when the system is stopped, and heat-exchanges the inorganic refrigerant flowing through the refrigerant circulation passage by the heat exchanging means when the system is in steady operation .   2. The fuel cell according to claim 1, wherein the fuel cell includes an anode channel to which the hydrogen-containing fuel gas is supplied, a cathode channel to which an oxygen-containing gas containing oxygen is supplied, the cathode channel and the anode channel. An electrolyte body disposed between the hydrogen separation metal layer for allowing hydrogen in the hydrogen-containing fuel gas supplied to the anode flow path to pass therethrough, and the hydrogen body. A fuel cell system comprising: a proton conductor layer made of ceramics for laminating the hydrogen that has passed through the separation metal layer in a hydrogen proton state and allowing the hydrogen to reach the cathode channel.   3. The fuel cell system according to claim 2, wherein the inorganic refrigerant is an inorganic refrigerant in a liquid state in an operating temperature range of the fuel cell.   4. The fuel cell system according to claim 1, wherein the inorganic refrigerant includes at least one of potassium nitrate, sodium nitrite, and sodium nitrate. 5.   5. The heat exchange means for performing heat exchange with the cooling medium is provided in at least a part of the refrigerant circulation passage or a portion communicating with the refrigerant circulation passage according to claim 1. A fuel cell system provided.   6. The fuel cell system according to claim 5, wherein the heat exchange means is configured to prevent the cooling medium from solidifying or to melt the solidified cooling medium.   7. The fuel cell system according to claim 5, wherein the heat exchange means performs heat exchange with the cooling medium using a gas or liquid heat exchange fluid.   8. The fuel cell system according to claim 7, wherein the heat exchanging means has a heat exchanging passage for circulating the heat exchanging fluid in parallel with the refrigerant circulation passage. According to claim 7 or 8, the heat exchange means is the upper Northern tank, a fuel cell system characterized by being configured to perform heat exchange between the cooling medium and the heat exchange fluids.   The heat exchange means according to any one of claims 7 to 9, wherein the heat exchange means exchanges heat between the cooling medium and the heat exchange fluid by causing the cooling medium and the heat exchange fluid to flow inside. A fuel cell system comprising a heat exchanging unit.   11. The fuel cell system according to any one of claims 7 to 10, wherein a fluid whose temperature is adjusted by a heat exchange means different from the heat exchange means is used as the heat exchange fluid.   The fuel cell system according to any one of claims 7 to 11, wherein combustion gas generated by combustion is used as the heat exchange fluid.   13. The fuel cell according to claim 7, wherein the fuel cell includes an anode flow path to which the hydrogen-containing fuel gas is supplied, a cathode flow path to which an oxygen-containing gas containing oxygen is supplied, and the cathode flow. An electrolyte body disposed between the channel and the anode channel, and the oxygen-containing gas before being supplied to the cathode channel is used as the heat exchange fluid. Fuel cell system.   The fuel cell system according to any one of claims 7 to 13, wherein the fuel cell system includes a reforming reaction channel that generates a hydrogen-containing fuel gas from the reforming fuel, and a heating flow for heating the reforming reaction channel. And a reformer combustion gas before being supplied to the heating flow path as the heat exchange fluid.   15. The fuel cell system according to claim 7, wherein the fuel cell system heats a reforming reaction channel that generates a hydrogen-containing fuel gas containing hydrogen from a reforming fuel, and the reforming reaction channel. A fuel cell system comprising a reformer having a heating flow path for use, and using a reformer combustion off-gas discharged from the heating flow path as the heat exchange fluid.   16. The fuel cell system according to any one of claims 5 to 15, wherein the heat exchange means includes a heater that directly heats the cooling medium.   The fuel cell system according to claim 16, wherein the heat exchange means includes an electric heater.   18. The fuel cell system according to claim 16 or 17, wherein the heat exchange means includes a catalytic combustion heater.   19. The fuel cell system according to claim 1, wherein the fuel cell system includes two systems of the refrigerant circulation passages, the inorganic refrigerant is circulated in one refrigerant circulation passage, and the other A fuel cell system characterized in that a gas refrigerant is circulated in a refrigerant circulation passage.   The fuel cell system according to any one of claims 1 to 19, wherein the inorganic refrigerant is solidified when the temperature is lowered to room temperature.

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