JP2010212049A - Fuel cell, and fuel cell power generation system equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell capable of improving the efficiency of exhaust heat recovery by reducing heat radiation from collector terminals. <P>SOLUTION: The fuel cell is provided at least with a unit cell 2 composed of a fuel electrode 8 and an oxidizer electrode 9 formed on either face of an electrolyte 7 and a pair of separators 1a, 1b which sandwich the electrolyte 7 or a stack 3 laminating a plurality of unit cells 2, collectors 4 arranged at either end of the unit cell 2 or the stack 3, collector terminals 5 fitted to the collectors 4, fuel gas manifolds supplying and exhausting fuel gas to the fuel electrode 8, oxidizer gas manifolds supplying and exhausting oxidizer gas to the oxidizer electrode 9, and a cooling water manifold supplying and exhausting cooling water collecting heat generated at the unit cells 2 or the stack 3. The collector terminals 5 are arranged in the vicinity of a cooling water inlet 10a of the cooling water manifold. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell that can reduce heat radiation from a current collecting terminal and improve exhaust heat recovery efficiency, and a fuel cell power generation system including the fuel cell.

  As shown in FIG. 7, a conventional general fuel cell supplies and discharges an electrolyte, a fuel electrode and an oxidant electrode formed on both surfaces of the electrolyte, and a fuel gas containing at least hydrogen in the fuel electrode, A unit cell 22 composed of a pair of separators 21a and 21b for supplying and discharging an oxidant gas containing at least oxygen, a stack 23 in which a plurality of unit cells 22 are stacked, a current collector 24 disposed at both ends of the stack 23, A collector terminal 25 provided on the current collector 24, a fuel gas manifold for supplying and discharging fuel gas, an oxidant gas manifold for supplying and discharging oxidant gas, and cooling water for recovering heat generated in the stack 23 are provided. It consists of a cooling water manifold that supplies and discharges.

  Here, the current collecting terminal 25 of the current collector 24 is provided for taking out a direct current, but since it is formed of a conductive metal or the like, it has high thermal conductivity, and both ends of the stack 23. The heat generated in the stack or the like during power generation is likely to be radiated from the current collecting terminal 25 due to the fact that the current collecting terminal 25 is increased in area for connecting the cables.

  And if heat dissipation increases, exhaust heat recovery efficiency will fall and total energy efficiency will fall. In addition, fuel gas or oxidant gas that is locally humidified in a part where heat dissipation is large, or water vapor generated by the reaction condenses in the flow path, causing flooding during power generation and voltage drop. Power generation performance may be reduced.

Therefore, in the conventional fuel cell, in order to reduce heat radiation from the current collecting terminal 25, a heat insulating material 26 is disposed around the current collecting terminal 25 to suppress heat radiation from the current collecting terminal 25 (for example, Patent Document 1).
JP 2005-327558 A

  However, in the conventional fuel cell, the amount of heat radiated from the current collecting terminal depends on the positional relationship with the cooling water manifold that supplies and discharges the cooling water that recovers the heat generated in the stack. Therefore, when the distance between the current collecting terminal and the cooling water outlet of the cooling water manifold is short, the temperature of the current collecting terminal rises and the temperature difference between the current collecting terminal and the outside air becomes large. Increases heat dissipation due to current collecting terminals. As a result, there has been a problem that exhaust heat recovery efficiency is reduced as compared with a case where the distance between the current collecting terminal and the cooling water outlet of the cooling water manifold is long.

  The present invention solves the above-described conventional problems, and by disposing a current collecting terminal in the vicinity of the cooling water inlet of the cooling water manifold, a fuel capable of reducing heat radiation from the current collecting terminal and improving exhaust heat recovery efficiency. An object is to provide a battery.

In order to solve the above-described conventional problems, a fuel cell of the present invention includes a unit cell or a plurality of unit cells each including a fuel electrode and an oxidant electrode formed on both surfaces of an electrolyte, and a pair of separators sandwiching the electrolyte. Stacked stacks, single cells or current collectors disposed at both ends of the stack, current collector terminals provided on the current collectors, a fuel gas manifold for supplying and discharging fuel gas to the fuel electrode, and an oxidant electrode An oxidant gas manifold that supplies and discharges oxidant gas and a cooling water manifold that supplies and discharges cooling water that recovers heat generated in the unit cell or the stack are provided at least, and a current collecting terminal is a cooling water inlet of the cooling water manifold. It is arranged in the vicinity.

  Thereby, since the current collection terminal is arrange | positioned in the vicinity of the cooling water inlet of the cooling water manifold with the lowest temperature in the stack, the temperature of the current collection terminal can be kept low. As a result, heat dissipation from the current collecting terminals can be suppressed, and exhaust heat recovery efficiency can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, by reducing the thermal radiation from a current collection terminal, exhaust heat recovery efficiency can be improved and the fuel cell excellent in total energy efficiency and a fuel cell power generation system using the same can be realized.

  A first invention is a unit cell comprising a fuel electrode and an oxidant electrode formed on both surfaces of an electrolyte and a pair of separators sandwiching the electrolyte, or a stack in which a plurality of unit cells are stacked, and both ends of the unit cell or the stack. A current collector disposed on the current collector, a current collector terminal provided on the current collector, a fuel gas manifold for supplying and discharging a fuel gas containing at least hydrogen to the fuel electrode, and an oxidant gas containing at least oxygen at the oxidant electrode And at least a cooling water manifold that supplies and discharges cooling water that recovers the heat generated by the single cell or stack, and a current collecting terminal is disposed near the cooling water inlet of the cooling water manifold It is a fuel cell of the composition to do.

  With this configuration, it is possible to suppress heat dissipation from the current collecting terminal, keep the temperature of the current collecting terminal low, and improve exhaust heat recovery efficiency.

  In a second aspect based on the first aspect, the current collecting terminal is disposed between the cooling water inlet of the cooling water manifold and the oxidant gas inlet of the oxidant gas manifold. As a result, when the dew point temperature at the oxidant gas inlet is the same or higher than the cooling water temperature and the dew point temperature at the fuel gas inlet is lower than the cooling water temperature, the fuel electrode side is in a low humidity state. Since the dew point temperature at the fuel gas inlet is prevented from further lowering due to heat radiation from the current collecting terminal, the resistance against impurities on the fuel electrode side can be kept high.

  In a third aspect based on the first aspect, the current collecting terminal is disposed between the cooling water inlet of the cooling water manifold and the fuel gas inlet of the fuel gas manifold. As a result, when the dew point temperature at the fuel gas inlet is the same or higher than the cooling water temperature and the dew point temperature at the oxidant gas inlet is lower than the cooling water temperature, the oxidant electrode side is in a low humidity state. However, since the dew point at the oxidant gas inlet is prevented from further lowering due to heat dissipation from the current collector terminal, the battery voltage can be kept high, and the resistance to impurities on the oxidant electrode side can be kept high. Can do.

  In a fourth aspect based on the first aspect, the cooling water inlet of the cooling water manifold is disposed in the vicinity of the current collecting terminal in the current collector. Thereby, a cooling water cools a current collection terminal via a collector with high heat conductivity. As a result, the temperature of the current collecting terminal is lowered, and the temperature difference between the current collecting terminal and the outside air is reduced, so that heat radiation from the current collecting terminal is suppressed and the exhaust heat recovery efficiency of the cooling water can be improved.

  In a fifth aspect based on the first aspect, the cooling water inlet of the cooling water manifold is provided in the current collecting terminal. Thereby, since the current collecting terminal is further cooled to lower the temperature, the exhaust heat recovery efficiency of the cooling water is further improved.

According to a sixth invention, in the fourth or fifth invention, the cooling water flow path connected to the cooling water inlet of the cooling water manifold is provided in the surface of the current collecting terminal. Thereby, a current collection terminal can be cooled efficiently and exhaust heat recovery efficiency of cooling water can further be improved.

  A seventh invention is a fuel cell power generation system according to any one of the first to sixth inventions, comprising at least the fuel cell, fuel processing means, and oxidant gas supply means. As a result, a fuel cell power generation system having excellent power generation performance and high exhaust heat recovery efficiency can be realized.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same configurations as those of the conventional technology described above, and detailed descriptions thereof will be omitted. The present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram showing a fuel cell according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the fuel cell according to Embodiment 1 of the present invention includes a stack 3 in which a plurality of single cells 2 are stacked, a current collector 4 disposed at both ends of the stack 3, and a current collector 4. Current collector terminal 5, fuel gas manifold for supplying and discharging fuel gas, oxidant gas manifold for supplying and discharging oxidant gas, and cooling water manifold for supplying and discharging cooling water for recovering heat generated in stack 3 The cooling water inlet 10a and the cooling water outlet 10b are at least configured.

  The unit cell 2 includes a membrane electrode assembly in which the fuel electrode 8 and the oxidant electrode 9 are formed on both surfaces of the electrolyte 7, and mixing or leakage of the fuel gas and the oxidant gas disposed around the membrane electrode assembly. Is sandwiched between a pair of separators 1a and 1b having a gas flow path for supplying and discharging fuel gas and oxidant gas.

  Here, the electrolyte 7 is composed of a solid polymer electrolyte made of a perfluorocarbon sulfonic acid polymer having hydrogen ion conductivity, for example.

  The fuel electrode 8 and the oxidant electrode 9 include a catalyst layer formed of a mixture of a catalyst having a noble metal such as platinum supported on porous carbon having high oxidation resistance and a polymer electrolyte having hydrogen ion conductivity, and a catalyst layer. It is composed of a gas diffusion layer having air permeability and electronic conductivity laminated on. At this time, a platinum-ruthenium alloy catalyst that suppresses poisoning by impurities contained in the fuel gas, particularly carbon monoxide (CO), is generally used as the catalyst for the fuel electrode 8. As the gas diffusion layer of the fuel electrode 8, carbon paper, carbon cloth, carbon non-woven fabric or the like subjected to water repellent treatment is used. The separators 1a and 1b are formed of a conductive material such as carbon.

  The stack 3 is formed by laminating a plurality of unit cells 2, arranging the current collector 4, the insulating plate and the end plate at both ends thereof, and firmly fastening them with a fastening rod. Here, the current collecting terminal 5 is provided so as to protrude from a part of the current collector 4 so as to be connected to a cable for taking out a direct current generated in the stack 3 to the outside. Further, a flow path (not shown) for supplying and discharging cooling water that is recovered by exchanging heat of the stack 3 generated during power generation is provided between the single cells 2. As shown in FIG. 1, cooling water is supplied to each flow path from a cooling water inlet 10 a of a cooling water manifold arranged at the top of the stack 3, and exhaust heat is recovered and arranged at the bottom of the stack 3. The cooling water manifold is connected to be discharged from the cooling water outlet 10b. In FIG. 1, the cooling water inlet 10 a and the cooling water outlet 10 b of the cooling water manifold are illustrated on the same side surface, but the present invention is not limited thereto. For example, the piping of the cooling water inlet 10a and the cooling water outlet 10b of the cooling water manifold may be arranged on different side surfaces, and the cooling water does not necessarily flow from the upper part to the lower part of the stack 3.

  At this time, it is important to arrange the current collecting terminal 5 in the vicinity of the cooling water inlet 10a of the cooling water manifold having the lowest temperature in the stack 3, as described below.

  In addition, a heat insulating material 6 is disposed around the stack 3 to prevent heat radiation to the outside of the stack 3 and to keep the stack 3 at a stable temperature.

  The fuel cell configured as described above generates power by supplying a fuel gas containing at least hydrogen to the fuel electrode 8 of the unit cell 2 constituting the stack 3 and supplying an oxidant gas containing at least oxygen to the oxidant electrode 9. To do.

  Below, the arrangement | positioning relationship between the current collection terminal 5 of the collector 4 which is the point of this Embodiment and the cooling water inlet 10a of a cooling water manifold is demonstrated using FIG.

  FIG. 2 is a schematic plan view showing the arrangement relationship between the cooling water inlet of the cooling water manifold and the current collecting terminal 5 of the fuel cell according to Embodiment 1 of the present invention. FIG. 2 shows the cooling water manifold as viewed from the cooling water inlet 10a side.

  As shown in FIG. 2, the stack 3 around the upper side of the current collector 4 has a cooling water inlet 10a of the cooling water manifold, a fuel gas inlet 11a of the fuel gas manifold, and an oxidant gas inlet 12a of the oxidant gas manifold. Has been placed. The stack 3 around the lower side of the current collector 4 is provided with a cooling water outlet 10b of the cooling water manifold, a fuel gas outlet 11b of the fuel gas manifold, and an oxidant gas outlet 12b of the oxidant gas manifold. .

  The current collector terminal 5 of the current collector 4 is provided in the vicinity of the cooling water inlet 10a of the cooling water manifold and between the oxidant gas inlet 12a of the oxidant gas manifold. The vicinity of the cooling water inlet 10 a of the cooling water manifold means that the shortest distance from the outer periphery of the cooling water inlet 10 a of the cooling water manifold to the outer periphery of the current collecting terminal 5 is 20 mm or less or twice the terminal width of the current collecting terminal 5. Within the following distance range. In particular, it is preferable that the current collector terminal 5 is in contact with the outer periphery of the cooling water inlet 10a of the cooling water manifold.

  Hereinafter, the exhaust heat recovery efficiency of the fuel cell power generation system in which the current collector terminal of the current collector described above is disposed in the vicinity of the cooling water inlet of the cooling water manifold will be specifically described.

  Therefore, the fuel cell of the present embodiment includes a fuel processing means for supplying a fuel gas containing hydrogen generated by reforming city gas to the fuel electrode 8 side, and oxygen in the atmosphere on the oxidant electrode 9 side. The fuel cell power generation system was configured by connecting an oxidant gas supply means for supplying the oxidant gas.

  First, the fuel processing means will be specifically described below.

  The fuel processing means includes at least a desulfurization section, a reforming section, a carbon monoxide shift section, and a carbon monoxide removal section. At this time, the desulfurization unit adsorbs and removes sulfur compounds contained in the odorant of the raw material gas such as city gas containing hydrocarbons such as methane. The reforming unit reforms a raw material gas containing hydrocarbon such as methane into a fuel gas containing hydrogen. In addition, the carbon monoxide conversion unit converts carbon monoxide generated by the reforming reaction, and the carbon monoxide removal unit further selectively oxidizes and removes carbon monoxide.

  That is, the raw material gas is desulfurized in the desulfurization section and then reformed in the reforming section to become a fuel gas containing hydrogen. At this time, for example, when methane is used as the raw material gas, the reaction shown in (Chemical Formula 1) and (Chemical Formula 2) occurs in the reforming unit with water vapor to generate hydrogen.

  In addition, the reaction shown in (Chemical Formula 3) is performed by summing up all reactions occurring in the reforming section.

  However, the reformed gas generated in the reforming section contains about 10% carbon monoxide in addition to hydrogen. The carbon monoxide poisons the platinum catalyst contained in the fuel electrode 8 in the operating temperature range of the stack 3 and reduces the catalytic activity. Therefore, carbon monoxide generated in the reforming section is converted into carbon dioxide in the carbon monoxide conversion section as shown in the reaction formula (Chemical Formula 2). This reduces the concentration of carbon monoxide to about 5000 ppm.

  Further, the carbon monoxide having a reduced concentration is selectively oxidized with the air taken in from the atmosphere by the selective oxidizing air supply means by the reaction shown by (Chemical Formula 4) in the carbon monoxide removing section. As a result, the concentration of carbon monoxide is reduced to about 10 ppm or less which can suppress the decrease in the catalytic activity of the platinum catalyst of the fuel electrode 8.

  Further, an air bleed means for supplying air to the fuel electrode 8 during power generation was provided in front of the fuel electrode 8, and about 1 to 2% of air was mixed with the fuel gas generated by the fuel processing means. This further reduced the effect of the slight remaining carbon monoxide.

  With the above configuration, a fuel processing means was constructed.

  The fuel processing means is not limited to the steam reforming method, and may be a hydrogen generation method such as an autothermal method. Further, the air bleed means may be omitted depending on the concentration of carbon monoxide contained in the fuel gas.

  Next, the oxidant gas supply means will be specifically described.

  The oxidant gas supply unit includes a blower that takes in the oxidant gas, an impurity removal unit that removes impurities in the oxidant gas, and a humidifier that humidifies the oxidant gas. Then, the oxidant gas is humidified and supplied to the oxidant electrode 9 of the stack 3. Here, the oxidant gas is a general term for gases containing at least oxygen (or capable of supplying oxygen). For example, the atmosphere (air) is used.

  Next, the operation of the fuel cell power generation system having the following configuration will be specifically described.

  First, when a fuel gas is supplied to the fuel electrode 8 and an oxidant gas is supplied to the oxidant electrode 9 and a load is connected, hydrogen in the fuel gas is converted into a catalyst layer and an electrolyte of the fuel electrode 8 as shown in the reaction formula Electrons are emitted at the interface of 7 to become hydrogen ions.

  The released hydrogen ions move to the oxidant electrode 9 through the electrolyte 7 and receive electrons at the interface between the catalyst layer of the oxidant electrode 9 and the electrolyte 7. At this time, it reacts with oxygen in the oxidant gas supplied to the oxidant electrode 9 to generate water as shown in the reaction formula (Formula 6).

  When the above reactions are combined, the reaction shown in (Chemical Formula 7) is performed.

  The flow of electrons flowing through the load can be used as direct current electric energy. The series of reactions is an exothermic reaction. Therefore, the exhaust heat generated in the stack 3 can be used as thermal energy such as hot water by recovering heat by exchanging with the cooling water supplied from the cooling water inlet 10a of the cooling water manifold.

  In general, the temperature of the stack 3 is determined by the magnitude of the direct current during power generation and the temperature of the cooling water, and is lowest in the vicinity of the cooling water inlet 10a of the cooling water manifold and highest in the vicinity of the cooling water outlet 10b of the cooling water manifold. Become.

  Specifically, in the fuel cell according to Embodiment 1 of the present invention, the temperature of the cooling water inlet 10a was about 60 ° C., and the temperature of the cooling water outlet 10b was about 70 ° C.

  At this time, generally, since the current collector 4 and the current collector terminal 5 are made of a metal conductor having high thermal conductivity, heat is radiated through the current collector terminal 5 in a portion in contact with the outside air.

  However, in the fuel cell according to Embodiment 1 of the present invention, the current collecting terminal 5 is disposed in the vicinity of the cooling water inlet 10a of the cooling water manifold having the lowest temperature in the stack 3, so that the heat radiation of the current collecting terminal is performed. Is absorbed by the cooling water. As a result, compared with the case where it is not arranged in the vicinity, heat radiation from the stack 3 to the outside is suppressed, and the exhaust heat recovery efficiency can be kept high.

In the fuel cell according to Embodiment 1 of the present invention, the dew point temperature of the fuel gas inlet 11a is about 55.
C., and the dew point temperature of the oxidant gas inlet 12a was about 65.degree. At this time, when the temperature near the center of the power generation surface of the stack 3 is an average of the temperature of the cooling water inlet 10a and the temperature of the cooling water outlet 10b, the temperature of the stack 3 is about 65 ° C. Therefore, the humidity of the fuel gas inlet 11a is changed from a high humidity state to a low humidity state with little water vapor.

  In general, when the fuel electrode 8 side is in a low humidity state, for example, impurities contained in the fuel gas, particularly carbon monoxide, poisons the catalyst of the fuel electrode 8, so that the generated voltage or the like depends on the degree of low humidity. The power generation performance may be reduced.

  However, in the fuel cell according to Embodiment 1 of the present invention, the current collecting terminal 5 is disposed between the oxidant gas inlet 12a of the oxidant gas manifold and the cooling water inlet 10a of the cooling water manifold. Condensation of water vapor due to heat dissipation can be suppressed. As a result, the fuel gas inlet 11a is suppressed from being in a lower humidity state, and the resistance to impurities on the fuel electrode 8 side is kept high, so that stable power generation performance can be maintained.

(Embodiment 2)
Hereinafter, a fuel cell according to Embodiment 2 of the present invention will be described with reference to FIG.

  FIG. 3 is a schematic plan view showing the positional relationship between the cooling water inlet and the current collecting terminal of the cooling water manifold of the fuel cell according to Embodiment 2 of the present invention.

  That is, as shown in FIG. 3, the fuel cell of the present embodiment is implemented in that the current collecting terminal 5 is arranged between the cooling water inlet 10a of the cooling water manifold and the fuel gas inlet 11a of the fuel gas manifold. This is different from the first form. The constituent elements of the fuel cell other than the arrangement relationship between the cooling water inlet and the current collecting terminal of the cooling water manifold are the same as those in the first embodiment, and thus the description thereof is omitted.

  Therefore, in the following, differences from the first embodiment will be mainly described in detail.

  First, as described in the first embodiment, the temperature of the cooling water inlet 10a during power generation of the fuel cell of the present embodiment is about 60 ° C., and the temperature of the cooling water outlet 10b is about 70 ° C. The dew point temperature of the fuel gas inlet 11a is about 65 ° C., and the dew point temperature of the oxidant gas inlet 12a is about 55 ° C. At this time, if the temperature near the center of the power generation surface of the stack 3 is the average of the temperature of the cooling water inlet 10a and the temperature of the cooling water outlet 10b, the temperature of the stack 3 is about 65 ° C. Therefore, the humidity of the oxidant gas inlet 12a is changed from a high humidity state to a low humidity state with little water vapor.

  In general, when the oxidant electrode 9 side is in a low humidity state, for example, impurities contained in the oxidant gas, for example, sulfur compounds such as sulfur dioxide, nitrogen oxides or ammonia contained in the atmosphere, Adhere (adsorb) to the catalyst. As a result, the chemical reaction necessary for power generation may be hindered, so that power generation performance such as power generation voltage may be reduced depending on the degree of low humidity.

  However, in the fuel cell according to Embodiment 2 of the present invention, the current collecting terminal 5 is disposed between the fuel gas inlet 11a of the fuel gas manifold and the cooling water inlet 10a of the cooling water manifold, so that heat is radiated from the current collecting terminal 5. It is possible to suppress the condensation of water vapor. As a result, the oxidant gas inlet 12a is suppressed from becoming a humidity state lower than that, and the resistance against impurities on the oxidant electrode 9 side is kept high, and stable power generation performance can be maintained.

(Embodiment 3)
Hereinafter, a fuel cell according to Embodiment 3 of the present invention will be described with reference to FIG.

  FIG. 4 is a schematic plan view showing the arrangement relationship between the cooling water inlet and the current collecting terminal of the cooling water manifold of the fuel cell according to Embodiment 3 of the present invention.

  That is, as shown in FIG. 4, the fuel cell of the present embodiment is different from that of the first embodiment in that the cooling water inlet 10a of the cooling water manifold is provided in the current collector 4 near the current collecting terminal 5. Is different. The constituent elements of the fuel cell other than the arrangement relationship between the cooling water inlet and the current collecting terminal of the cooling water manifold are the same as those in the first embodiment, and thus the description thereof is omitted.

  As shown in FIG. 4, in the fuel cell of the present embodiment, the cooling water inlet of the cooling water manifold is disposed near the base of the current collecting terminal 5 in the current collector 4 to reduce heat dissipation of the current collecting terminal 5. It is the structure to do.

  Here, the vicinity of the current collecting terminal 5 is a distance in which the shortest distance from the outer periphery of the cooling water inlet 10 a of the cooling water manifold to the outer periphery of the current collecting terminal 5 is 20 mm or less or twice the terminal width of the current collecting terminal 5. Is within the range. In particular, the cooling water inlet 10 a of the cooling water manifold is preferably arranged at the base of the current collecting terminal 5 of the current collector 4.

  At this time, in order to prevent corrosion of the current collector 4 and increase in the conductivity of the cooling water, the cooling water inlet 10a of the cooling water manifold is made of resin so that the cooling water does not directly contact the current collector 4 and the current collecting terminal 5. It is preferable to cover and configure with piping or resin.

  According to the present embodiment, the cooling water cools the current collecting terminal 5 via the current collector 4 having high thermal conductivity. Thereby, the temperature of the current collecting terminal 5 is lowered, and the difference between the current collecting terminal 5 and the outside air temperature is reduced. As a result, heat dissipation from the current collecting terminals 5 can be suppressed, and the exhaust heat recovery efficiency can be improved via the cooling water.

(Embodiment 4)
Hereinafter, a fuel cell according to Embodiment 4 of the present invention will be described with reference to FIG.

  FIG. 5 is a schematic plan view showing the positional relationship between the cooling water inlet and the current collecting terminal of the cooling water manifold of the fuel cell according to Embodiment 4 of the present invention.

  That is, as shown in FIG. 5, the fuel cell according to the present embodiment is different from the first embodiment in that a cooling water inlet 10 a of a cooling water manifold is provided at the current collecting terminal 5. The constituent elements of the fuel cell other than the arrangement relationship between the cooling water inlet and the current collecting terminal of the cooling water manifold are the same as those in the first embodiment, and thus the description thereof is omitted.

  As shown in FIG. 5, in the fuel cell of the present embodiment, a cooling water inlet 10 a of a cooling water manifold is disposed in a current collecting terminal 5 provided to protrude from the current collector 4. This configuration reduces heat dissipation.

  At this time, in order to prevent corrosion of the current collector 4 and increase in the conductivity of the cooling water, the cooling water inlet 10a of the cooling water manifold is made of resin so that the cooling water does not directly contact the current collector 4 and the current collecting terminal 5. It is preferable to cover and configure with piping or resin.

  According to the configuration of the present embodiment, the current collecting terminal 5 is directly cooled to lower the temperature of the current collecting terminal 5. As a result, heat dissipation from the current collecting terminals 5 can be efficiently suppressed, and the exhaust heat recovery efficiency of the cooling water can be further improved.

In the third and fourth embodiments, the configuration in which the cooling water inlet of the cooling water manifold penetrates the current collecting terminal or the current collector in the vicinity thereof is described as an example, but the present invention is not limited to this. For example, as shown in FIG. 6, a cooling water flow path 10 c that is connected to the cooling water inlet 10 a of the cooling water manifold and flows therethrough may be provided in the surface of the current collecting terminal 5. At this time, the cooling water flow path 10c needs to be a sealed space. As a result, it is possible to efficiently cool the entire current collecting terminal, further improve the exhaust heat recovery efficiency of the cooling water, and realize a fuel cell with excellent power generation performance and high overall energy efficiency. Moreover, even if the cooling water flow path is provided in the third embodiment, the same effect can be obtained.

  In each embodiment, the configuration of the fuel cell has been mainly described. However, the present invention is not limited to this, and a fuel cell power generation system can be constructed by providing a fuel cell with a fuel processing unit and an oxidant gas supply unit. . As a result, a fuel cell power generation system having excellent power generation performance and high exhaust heat recovery efficiency can be realized.

  INDUSTRIAL APPLICABILITY The present invention is useful in technical fields such as a fuel cell using a polymer type solid electrolyte membrane, a fuel cell device, and a stationary fuel cell power generation system, where improvement in exhaust heat recovery efficiency is desired.

1 is a schematic configuration diagram showing a fuel cell according to Embodiment 1 of the present invention. 1 is a schematic plan view showing an arrangement relationship between a cooling water inlet and a current collecting terminal of a cooling water manifold of a fuel cell according to Embodiment 1 of the present invention. Schematic plan view showing the arrangement relationship between the cooling water inlet and the current collecting terminal of the cooling water manifold of the fuel cell according to Embodiment 2 of the present invention. Schematic plan view showing the arrangement relationship between the cooling water inlet and the current collecting terminal of the cooling water manifold of the fuel cell according to Embodiment 3 of the present invention. Schematic plan view showing the arrangement relationship between the cooling water inlet and the current collecting terminal of the cooling water manifold of the fuel cell according to Embodiment 4 of the present invention. Schematic plan view showing the structure of a current collecting terminal of another example of the fuel cell according to Embodiment 4 of the present invention. Schematic configuration diagram showing a conventional fuel cell

DESCRIPTION OF SYMBOLS 1a, 1b, 21a, 21b Separator 2,22 Single cell 3,23 Stack 4,24 Current collector 5,25 Current collecting terminal 6,26 Heat insulating material 7 Electrolyte 8 Fuel electrode 9 Oxidant electrode 10a Cooling water inlet 10b Cooling water Outlet 10c Cooling water flow path 11a Fuel gas inlet 11b Fuel gas outlet 12a Oxidant gas inlet 12b Oxidant gas outlet

Claims (7)

A unit cell composed of a fuel electrode and an oxidant electrode formed on both surfaces of the electrolyte, and a pair of separators sandwiching the electrolyte, or a stack in which a plurality of the unit cells are stacked, and arranged at both ends of the unit cell or the stack Current collector, a current collector terminal provided on the current collector, a fuel gas manifold for supplying and discharging a fuel gas containing at least hydrogen to the fuel electrode, and an oxidizer containing at least oxygen in the oxidizer electrode An oxidant gas manifold that supplies and discharges gas; and a cooling water manifold that supplies and discharges cooling water that recovers heat generated in the single cell or the stack, and the current collector terminal is used to cool the cooling water manifold. A fuel cell placed near the water inlet. The fuel cell according to claim 1, wherein the current collecting terminal is disposed between the cooling water inlet of the cooling water manifold and the oxidant gas inlet of the oxidant gas manifold. The fuel cell according to claim 1, wherein the current collecting terminal is disposed between the cooling water inlet of the cooling water manifold and the fuel gas inlet of the fuel gas manifold. The fuel cell according to claim 1, wherein the cooling water inlet of the cooling water manifold is disposed in the vicinity of the current collecting terminal in the current collector. The fuel cell according to claim 1, wherein the cooling water inlet of the cooling water manifold is provided in the current collecting terminal. 6. The fuel cell according to claim 4, wherein a cooling water passage connected to the cooling water inlet of the cooling water manifold is provided in a surface of the current collecting terminal. A fuel cell power generation system comprising at least the fuel cell according to any one of claims 1 to 6, a fuel processing unit, and an oxidant gas supply unit.

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