JP2006216431A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of equalizing a temperature distribution of a fuel cell. <P>SOLUTION: A cooling medium passage 12 for running a cooling medium for cooling a unit cell 1 is formed so as to cross an air passage 11. A cooling medium internal introduction manifold 13 for introducing the cooling medium into the cooling medium passage 12 is divided into a cooling medium internal introduction manifold 13a located on the upstream side of the air passage 11 and a cooling medium internal introduction manifold 13b located on the downstream side thereof by a movable part 24, and the flow rates of the cooling medium introduced into the cooling medium internal introduction manifolds 13a and 13b are controlled by flow control valves 39 and 40. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system, and more particularly to cooling of a fuel cell.

  A fuel cell is a device that continuously supplies fuel and discharges combustible organisms, and changes the chemical energy of the fuel directly into electrical energy, providing high power generation efficiency, low air pollutants, and noise. It is characterized by a small amount of

  A unit cell (unit cell) serving as a power generation unit of a fuel cell has a structure in which gas diffusion electrodes are joined to both surfaces of an electrolyte and sandwiched between separators each having a gas flow path on both surfaces. The power generation principle of a fuel cell is such that a fuel gas such as hydrogen is applied to one gas diffusion electrode (fuel electrode) side of the unit cell having such a structure, and air is applied to the other gas diffusion electrode (oxygen electrode) side. By flowing an oxidant gas containing oxygen, the fuel is oxidized, and the change in free energy at that time is taken out as electric energy through separators arranged at both ends of the unit cell.

  It is well known that there is a close relationship between the output of such a fuel cell and the cell temperature, and it is necessary to maintain the cell temperature optimally in order to obtain the maximum output. For example, in the case of a polymer electrolyte fuel cell that uses reformed gas instead of pure hydrogen as the fuel gas, if the cell temperature is too low, the electrode catalyst in the gas diffusion electrode is poisoned by carbon monoxide in the reformed gas. , Power generation performance is reduced. In addition, when the cell temperature becomes a temperature equal to or higher than the boiling point of the humidified water contained in the solid polymer electrolyte membrane, the water vapor behavior changes and the power generation performance decreases. Moreover, when the cell temperature reaches a temperature equal to or higher than the glass transition point of the solid polymer electrolyte membrane, the electrolyte membrane is transformed and power generation performance is reduced. Further, it has been confirmed that the temperature on the outlet side of the oxidant gas is higher than that on the inlet side in the cell plane, and it is well known that the temperature varies within the unit cell. It is also clear that the variation in temperature distribution changes with deterioration.

Therefore, in the fuel cell, it is necessary to maintain each unit cell at the optimum temperature. As a cooling method, a cooling surface parallel to the fuel gas / oxidant gas flow path is provided, and a refrigerant is circulated therethrough via a separator. A cooling method is often used. In the configuration of the fuel cell disclosed in Patent Document 1, a plurality of refrigerant flow paths in the cell plane are provided, and the temperature gradient generated in the cell plane is made uniform by controlling the flow rate and flow direction of the refrigerant flowing therethrough. It has become.
JP-A-8-329960

  However, the above-described invention has a problem that the refrigerant flow area is fixed and cannot cope with various operation modes, that is, changes in temperature distribution accompanying changes in the output of the fuel cell.

  The present invention has been invented in order to solve such problems, and it is an object of the present invention to make the temperature of the fuel cell uniform by changing the region where the cooling medium flows in accordance with the operation mode of the seed master.

  In the present invention, the oxidant gas separator having an oxidant gas flow path through which the oxidant gas flows, the fuel gas separator having a fuel gas flow path through which the fuel gas flows, and the oxidant gas separator and the fuel gas separator are sandwiched. Cooling medium having a cooling medium flow path arranged so that the cooling medium for cooling the unit cell composed of the electrolyte membrane, the oxidant gas separator, the fuel gas separator, and the electrolyte membrane flows and intersects the flow direction of the oxidant gas In a fuel cell system having a fuel cell comprising a medium separator and a cooling medium introduction manifold that communicates with the cooling medium passage and introduces the cooling medium into the cooling medium passage, the inside of the cooling medium introduction manifold contains oxidant gas. Dividing means that divides in the direction intersecting the flow direction and is movable in the cooling medium introduction manifold based on the operating state of the fuel cell , And a coolant flow rate control means for controlling each based on the flow rate of the cooling medium to be introduced into the divided coolant inlet manifold to the operating state of the fuel cell by dividing means.

  According to the present invention, in a fuel cell system having a fuel cell provided so that the cooling medium flow path intersects the air flow path, the cooling medium introduction manifold is divided by the movable dividing means, and the divided cooling medium introduction manifold is divided. Since the flow rate of the cooling medium introduced into the air flow path is controlled, the flow area of the cooling medium is changed according to the output of the fuel cell, for example, on the upstream side and the downstream side of the air flow path, and the flow rate of the refrigerant is controlled. The temperature can be made uniform.

  The unit cell 1 constituting the fuel cell stack 30 used in the first embodiment of the present invention will be described with reference to the schematic configuration diagram of FIG.

  The unit cell 1 includes an electrolyte membrane 2, an anode catalyst layer 3a and a cathode catalyst layer 3b sandwiching the electrolyte membrane 2, an anode gas diffusion layer 4a provided outside the anode catalyst layer 3a and the cathode catalyst layer 3b, and a cathode gas diffusion. A membrane electrode assembly 5 (MEA: Membrane Electrode Assembly) composed of the layer 4b is provided. Further, an anode separator (fuel gas separator) 6 provided outside the anode gas diffusion layer 4a and a cathode separator (oxidant gas separator) 7 provided outside the cathode gas diffusion layer 4b are provided. Further, a refrigerant separator (cooling medium separator) 8 is provided outside the cathode separator 7. Further, an edge seal 9 is provided so that hydrogen or air does not leak from the MEA 5.

  The anode separator 6 includes a hydrogen channel (fuel gas channel) 10 for diffusing hydrogen (fuel gas) into the anode gas diffusion layer 4a, and the cathode separator 7 includes air (oxidant gas) in the cathode gas diffusion layer 4b. ) Is provided with an air flow path (oxidant gas flow path) 11. The hydrogen flow path 10 and the air flow path 11 are linear flow paths, the hydrogen flow path 10 and the air flow path 11 are arranged in parallel, and in the unit cell 1, hydrogen flowing through the hydrogen flow path 10 and The air flow through the air flow path 11 is in the opposite direction. In addition, you may provide so that the hydrogen flow path 10 and the air flow path 11 may cross | intersect.

  The refrigerant separator 8 will be described in detail with reference to FIG. FIG. 2 is a front view of the refrigerant separator 8 as seen from the cathode separator 7.

  The refrigerant separator 8 includes a refrigerant flow path 12 (indicated by 12a and 12b in FIG. 2) through which a refrigerant that cools the unit cell 1, and a rib portion 12c (shaded portion in FIG. 2) that forms the refrigerant flow path 12. A refrigerant internal introduction manifold (cooling medium introduction manifold) 13 for introducing the refrigerant into the refrigerant flow path 12 and a refrigerant internal discharge manifold 14 for discharging the refrigerant from the refrigerant flow path 12 are provided. Further, a hydrogen introduction manifold 20 that introduces hydrogen into the hydrogen flow path 10, a hydrogen discharge manifold 21 that discharges hydrogen not used in the power generation reaction in the unit cell 1 from the hydrogen flow path 10, and air into the air flow path 11. An air supply manifold 22 to be introduced and an air discharge manifold 23 for discharging air that has not been used in the power generation reaction in the unit cell 1 from the air flow path 11 are provided.

  The refrigerant flow path 12 has, for example, a linear shape, and is disposed so as to intersect the air flow that flows through the air flow path 11.

  In the refrigerant internal introduction manifold 13 (indicated by 13a and 13b in FIG. 2) and the refrigerant internal discharge manifold 14 (indicated by 14a and 14b in FIG. 2), movable parts (dividing means) 24 and 25 described later are provided. Each is arranged.

  Next, the fuel cell stack 30 in which the unit cells 1 are stacked will be described with reference to FIGS. FIG. 3 is a schematic perspective view of the fuel cell stack 30, and FIG. 4 is a cross-sectional view taken along plane A of FIG.

  The fuel cell stack 30 includes end plates 32c and 32d on both sides of a stack portion 31 in which, for example, 100 to 200 unit cells 1 are stacked, pressurizes from the outside of the end plates 32c and 32d, and tie rods (not shown) and bolts ( (Not shown). Note that the surface pressure of the stack portion 31 may be made constant by a spring or the like. The fuel cell stack 30 also includes a refrigerant introduction manifold 33 that introduces refrigerant into the refrigerant internal introduction manifold 13 and a refrigerant discharge hold 34 that discharges the refrigerant from the refrigerant internal discharge manifold 14. Furthermore, the movable part 24 which divides | segments the refrigerant | coolant internal introduction manifold 13 in the lamination direction of the unit cell 1 and the movable part 25 which divides the refrigerant | coolant internal discharge manifold 14 in the lamination direction of the unit cell 1 are provided.

  Here, the movable parts 24 and 25 will be described with reference to the exploded schematic view of the unit cell 1 of FIG. 4 or FIG. 5, only the MEA 5, the anode separator 6, the cathode separator 7, the refrigerant separator 8, and the movable parts 24 and 25 are shown for explanation. The hydrogen separator 11 is used for the anode separator 6, and the air channel 12 is used for the cathode separator 7. The shape is omitted. Further, a part of the refrigerant flow path 12 is also omitted.

  The movable portion 24 connects one end portion 24c to one end plate 32c, and the end portion 24c is movable with respect to the end plate 32c. The other end 24 d is connected to the end of the partition portion 35 provided in the refrigerant introduction manifold 33 by the stretchable connecting portion 36. Although not shown in detail, the refrigerant internal introduction manifold 13 can be moved by moving the end 24d of the movable portion 24 by a motor or the like. In addition, the movable part 24 can move smoothly because the connection part 36 expands and contracts. The movable part 24 is preferably a highly rigid member. Furthermore, the width of the movable portion 24 is made smaller than the width between adjacent refrigerant flow paths 12, that is, the width of the rib portion 12c (shaded portion in FIG. 5). As a result, it is possible to eliminate the refrigerant flow path 12 in which it is difficult for the refrigerant to flow due to pressure loss due to the rib portion 12 c in the refrigerant flow path 12.

  In this embodiment, one end 24c of the movable portion 24 is connected to the end plate 32c so as to be movable with respect to the end plate 32c, and the movable portion 24 passes through the refrigerant internal introduction manifold 13 in the air passage 11. However, the end portion 24c may be fixed to the end plate 32c.

  In the following, in the divided refrigerant internal introduction manifold 13, refrigerant internal discharge manifold 14, and refrigerant flow path 12, an area corresponding to the upstream side of the air flow path 11 is indicated by a suffix “a”, and an area corresponding to the downstream side of the air flow path 11 is illustrated. Indicated by the subscript b.

  By moving the movable part 24 in the refrigerant internal introduction manifold 13 in the air flow direction, the areas of the refrigerant internal introduction manifolds 13a and 13b, that is, the areas of the refrigerant flow paths 12a and 12b can be changed.

  Further, the refrigerant introduction manifold 33 is divided by the partition part 35, and the air flow path 11 or the hydrogen flow path is obtained by introducing refrigerants having different flow rates into the refrigerant introduction manifolds 33a and 33b by flow rate control valves 39 and 40, which will be described later. The upstream side and the downstream side of 10 can be cooled by different flow rates of refrigerant, and the temperatures of the air flow path 11 or the upstream and downstream sides of the hydrogen flow path 10 can be controlled.

  The movable portion 25 has the same configuration as that of the movable portion 24, and the fuel internal discharge manifold 14 is divided so that the refrigerant that has passed through the refrigerant flow paths 12 a and 12 b is not mixed in the fuel cell stack 30. It is discharged to the outside of the stack 30. Further, it is desirable that the movable portion 24 and the movable portion 25 are located at substantially the same position in the refrigerant internal introduction manifold 13 and the refrigerant internal discharge manifold 14 with respect to the refrigerant flow direction. By setting substantially the same position with respect to the flow direction of the refrigerant, a rapid change in pressure in the refrigerant flow path 12 can be prevented, and deterioration of the fuel cell stack 30 can be suppressed.

  A fuel cell system including a fuel cell stack 30 in which unit cells 1 are stacked will be described with reference to FIG. The fuel cell system controls a pump 37 for circulating the refrigerant, a radiator 38 for cooling the refrigerant, a flow rate control valve 39 for controlling a flow rate of the refrigerant flowing to the refrigerant internal introduction manifold 13a, and a flow rate of the refrigerant flowing to the refrigerant internal introduction manifold 13b. And a flow rate control valve 40. Further, a hydrogen cylinder 41 for supplying hydrogen to the fuel cell stack and a compressor 42 for supplying air are provided.

  Further, the overall flow rate of the refrigerant by the pump 37 is controlled according to the output of the fuel cell stack 30, the flow rate of the refrigerant flowing through the refrigerant flow paths 12 a and 12 b is controlled by the flow rate control valves 39 and 40, and the movable parts 24 and 25. A controller 100 for controlling a motor (not shown) for moving the motor.

  Although the fuel cell stack 30 may change in the temperature distribution in the fuel cell stack 30 depending on the output of the fuel cell stack 30, the refrigerant internal introduction manifolds 13a and 13b are moved by moving the movable parts 24 and 25. Is changed, that is, the areas of the refrigerant flow paths 12a and 12b are changed. In this embodiment, the movable portions 24 and 25 are moved from a map or the like set in advance according to the output of the fuel cell stack 30 or the like to change the areas of the refrigerant internal introduction manifolds 13a and 13b and the refrigerant internal discharge manifolds 14a and 14b. In addition, the movable parts 24 and 25 move only between the rib parts 12c in the refrigerant internal manifold 13 and the refrigerant internal discharge manifold 14, and when the movable parts 24 and 25 stop, the movable parts 24 and 25 become the refrigerant flow path 12a, It moves so as not to reduce the flow path area of 12b. As a result, it is possible to prevent an increase in pressure loss in the refrigerant flow paths 12a and 12b, and to suppress deterioration of the fuel cell stack 30.

  Further, the flow rate of the refrigerant flowing through the refrigerant flow paths 12a and 12b is controlled by the flow control valves 39 and 40 based on the output of the fuel cell stack 30 and the like.

  For example, when the temperature on the downstream side of the air flow path 11 is expected to increase, the movable portions 24 and 25 are moved based on a preset map, and the refrigerant internal introduction manifold 13b and the refrigerant internal discharge manifold 14b are in the region. To widen. Further, by increasing the flow rate of the refrigerant flowing through the refrigerant flow path 12b, it is possible to suppress an increase in temperature on the downstream side of the air flow path 11, and to make the temperature of the fuel cell stack 30 uniform.

The moving amount of the movable parts 24 and 25 is, for example,
(Refrigerant channels 12a, 12b width + rib portion 12c width) × n Formula (1)
And n is a natural number, and n is set by a map based on the output of the fuel cell stack 30, the cooling capacity of a radiator (not shown) for cooling the refrigerant, the size of the unit cell 1, the temperature distribution, and the like. Control the amount of movement.

  In the fuel cell stack 30, flooding tends to occur as the air flow channel 11 is blocked by the generated water generated by the power generation reaction as it becomes downstream of the air flow channel 11. In such a case, the downstream of the air flow channel 11, That is, the movable parts 24 and 25 are moved so that the flow rate of the refrigerant flowing through the refrigerant flow path 12b decreases, and the flow rate is controlled by the flow rate control valves 39 and 40, thereby increasing the temperature downstream of the air flow path 11; Flooding downstream of the air flow path 11 is suppressed.

  Further, when the fuel cell system is restarted after being stopped, flooding is particularly likely to occur downstream of the air flow path 11. Therefore, in this embodiment, the refrigerant internal introduction manifold 13b is narrowed so that the vicinity of the downstream of the air flow path 11 is not cooled when the fuel cell system is stopped, and the flow rate introduced into the refrigerant internal introduction manifold 13b by the flow rate control valve 40 is set. Reduce. As a result, flooding downstream of the air flow path 11 at the time of restart can be suppressed, and the fuel cell system can be quickly started up at the next startup. Further, freezing of water in the fuel cell stack 30 below freezing point can be suppressed.

  A refrigerant tank that temporarily stores the refrigerant may be provided. In this embodiment, the air flow path 11 has a linear shape, but may have a serpentine shape including a straight portion and a folded portion. In this case, the refrigerant flow path 12 is disposed so that the entire flow of air and the refrigerant flow path 12 intersect.

  Moreover, although one movable part 24 and 25 are provided in the refrigerant | coolant internal introduction manifold 13 and the refrigerant | coolant internal discharge manifold 14, respectively, you may provide two or more movable parts.

  The effect of 1st Embodiment of this invention is demonstrated.

  Movable parts 24 and 25 that divide the refrigerant internal introduction manifold 13 and the refrigerant internal discharge manifold 14 in the direction intersecting the air flow direction of the air flow path 11 are formed in the refrigerant internal introduction manifold 13 and the refrigerant internal discharge manifold 14 of the fuel cell stack 30. Furthermore, the movable parts 24 and 25 are movable within the refrigerant internal introduction manifold 13 and the refrigerant internal discharge manifold 14. Further, different flow rates of refrigerant are introduced into the refrigerant internal introduction manifolds 13a and 13b by the flow rate control valves 39 and 40, respectively. Accordingly, the region of the refrigerant internal introduction manifolds 13a and 13b can be changed, and further, the cooling capacity in the refrigerant flow paths 12a and 12b, that is, the air flow is controlled by controlling the refrigerant flow rate introduced into the refrigerant internal introduction manifolds 13a and 13b. The temperature can be controlled respectively on the upstream side and the downstream side of the path 11, the temperature of the fuel cell stack 30 can be made uniform, and the power generation efficiency of the fuel cell stack 30 can be improved.

  When flooding is likely to occur downstream of the air flow path 11, the temperature of the downstream of the air flow path 11 is increased by narrowing the area of the refrigerant internal introduction manifold 13b and reducing the flow rate of the refrigerant flowing through the refrigerant flow path 12b. And flooding can be suppressed. In addition, when the electrolyte membrane 2 is easy to dry, the drying of the electrolyte membrane 2 can be suppressed and deterioration of the fuel cell stack 30 can be suppressed particularly by increasing the refrigerant flow rate upstream of the air flow path 11. it can.

  Further, when the fuel cell system is stopped, the region of the refrigerant internal introduction manifold 13b is narrowed to reduce the flow rate of the refrigerant flowing through the refrigerant flow channel 12b, thereby suppressing the temperature downstream of the air flow channel 11 from decreasing. It can be started quickly when starting up. Further, when the fuel cell stack 30 is below freezing point, water may freeze in the fuel cell stack 30, but by reducing the amount of water remaining in the air flow path 11 when stopped, the ice in the air flow path 11 is reduced. The fuel cell system can be quickly started even when starting below freezing.

  Next, a fuel cell system according to a second embodiment of the present invention will be described with reference to the schematic diagram of FIG. In addition to the first embodiment, this embodiment includes temperature sensors 43, 44, 45, and 46 that detect the temperature of the refrigerant upstream and downstream of the refrigerant introduction manifold 33 and the refrigerant discharge manifold 34, respectively. Since other configurations are the same as those in the first embodiment, description thereof is omitted here.

  In this embodiment, the temperature of the refrigerant upstream and downstream of each of the refrigerant internal introduction manifolds 13a and 13b and the refrigerant internal discharge manifolds 14a and 14b is detected, and the flow rate is based on the detected temperature or the temperature difference between the upstream and downstream. By controlling the control valves 39 and 40, the refrigerant flow rates of the refrigerant flow paths 12a and 12b can be controlled, and the temperature of the fuel cell stack 30 can be accurately controlled.

  For example, when the regions of the refrigerant internal introduction manifolds 13a and 13b and the refrigerant internal discharge manifolds 14a and 14b are determined by the movable parts 24 and 25 according to the output of the fuel cell stack 30, the temperature sensors 43 and 45 of the refrigerant flow path 12a. If the temperature of the refrigerant detected by the temperature sensors 44 and 46 of the refrigerant flow path 12b is higher than the set temperature, the cooling capacity of the refrigerant flow path 12b is insufficient. Therefore, the opening degree of the flow control valve 40 is increased, and the refrigerant flow rate to the refrigerant flow path 12b is increased.

  Alternatively, when the temperature difference between the temperature sensor 45 and the temperature sensor 43 and the temperature difference between the temperature sensor 46 and the temperature sensor 44 are large, the amount of heat exchange of the refrigerant is large, that is, the temperature of the fuel cell stack 30 is high. Increase the flow rate.

  Further, the movable portions 24 and 25 are moved based on the temperature detected by the temperature sensors 43, 44, 45, and 46 or a map set in advance from the temperature difference, so that the refrigerant internal introduction manifolds 13a and 13b and the refrigerant internal discharge manifold 14a are moved. , 14b may be changed to control the refrigerant flow rate.

  The effect of 2nd Embodiment of this invention is demonstrated. In this embodiment, in addition to the effects of the first embodiment, the following effects can be obtained.

  In this embodiment, temperature sensors 43, 44, 45, and 46 are provided upstream and downstream of the refrigerant internal introduction manifolds 13a and 13b and the refrigerant internal discharge manifolds 14a and 14b, respectively. Accordingly, the temperature of the refrigerant introduced into the refrigerant internal introduction manifolds 13a and 13b or discharged from the refrigerant internal discharge manifolds 14a and 14b, that is, the temperature distribution of the fuel cell stack 30, can be accurately detected. The temperature can be adjusted quickly according to the distribution. As a result, the temperature of the fuel cell stack 30 can be made more uniform, and the power generation efficiency of the fuel cell stack can be further improved.

  Further, since the temperature distribution of the fuel cell stack 30 is accurately detected, the movable portions 24 and 25 are moved based on the detected temperature to change the regions of the refrigerant internal introduction manifolds 13a and 13b and the refrigerant internal discharge manifolds 14a and 14b. By controlling the refrigerant flow rate, the temperature of the fuel cell stack 30 can be made more uniform, and the power generation efficiency of the fuel cell stack can be further improved.

  Moreover, since the temperature of the fuel cell stack is accurately detected, flooding and drying of the electrolyte membrane 2 can be further suppressed based on the detected temperature.

  Next, a fuel cell system according to a third embodiment of the present invention will be described with reference to the schematic diagram of FIG. This embodiment includes humidity sensors (humidity detection means) 47 and 48 upstream and downstream of the air flow path 11 in addition to the second embodiment. Since other configurations are the same as those of the second embodiment, description thereof is omitted here. With this configuration, the humidity of the air passage 11 can be accurately detected.

  For example, when the humidity of the humidity sensor 48 is high, that is, when the humidity downstream of the air flow path 11 is high, flooding occurs downstream of the air flow path 11. , 25 is moved, for example, the higher the humidity, the narrower the region of the refrigerant internal introduction manifold 13b, the flow control valves 39 and 40 are controlled, and the refrigerant flow rate flowing through the refrigerant flow channel 12b is changed to the refrigerant flowing through the refrigerant flow channel 12a. Less than the flow rate. Thereby, the temperature on the downstream side of the air flow path 11 can be increased, and flooding downstream of the air flow path 11 can be suppressed. In addition, by controlling the flow rate of the refrigerant introduced into the refrigerant internal introduction manifold 13a by the flow control valve 39, the temperature on the upstream side of the air flow path 11, that is, the humidity can be controlled, and the temperature of the fuel cell stack 30 can be controlled. It can be made uniform and flooding can be suppressed.

  In addition, when the humidity of the humidity sensor 47 is low, the air is dry, and the electrolyte membrane 2 is dried, so that the conductivity of the electrolyte membrane 2 is lowered and the power generation efficiency of the fuel cell stack may be lowered. In this case, the movable parts 24 and 25 are moved according to a map set in advance based on the humidity. For example, the lower the humidity, the wider the region of the refrigerant internal introduction manifold 13a and the flow control valves 43 and 44 are controlled. Then, the refrigerant flow rate flowing through the refrigerant flow path 12a is made larger than the refrigerant flow rate flowing through the refrigerant flow path 12b. Thereby, the humidity on the upstream side of the air channel 11 can be increased, and drying of the electrolyte membrane 2 can be suppressed. In addition, by controlling the flow rate of the refrigerant introduced into the refrigerant internal introduction manifold 13b by the flow rate control valve 40, the temperature on the downstream side of the air flow path 11, that is, the humidity can be controlled, and the temperature of the fuel cell stack 30 can be controlled. It can be made uniform and the drying of the electrolyte membrane 2 can be suppressed.

  A dew point sensor may be used in place of the humidity sensors 47 and 48.

  The effect of the third embodiment of the present invention will be described. In this embodiment, in addition to the effects of the second embodiment, the following effects can be obtained.

  In this embodiment, humidity sensors 47 and 48 are provided upstream and downstream of the air flow path 11. Thereby, the humidity of the air flow path 11 can be accurately controlled by detecting the humidity of the air flow path 11 and controlling the movable parts 24 and 25 and the flow rate control valves 39 and 40 based on the humidity. . Therefore, flooding in the air flow path 11 can be further suppressed, and drying of the electrolyte membrane 2 can be further suppressed.

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea.

  It can be used for automobiles equipped with a fuel cell stack where the load fluctuation of the fuel cell stack is severe.

It is a schematic block diagram of the unit cell of this invention. It is the schematic of the refrigerant separator of this invention. 1 is a schematic perspective view of a fuel cell stack according to the present invention. It is sectional drawing in the A plane of FIG. It is an exploded view of the unit cell of this invention. 1 is a fuel cell system according to a first embodiment of the present invention. It is a fuel cell system of 2nd Embodiment of this invention. It is a fuel cell system of 3rd Embodiment of this invention.

Explanation of symbols

1 unit cell 2 electrolyte membrane 6 anode separator (fuel gas separator)
7 Cathode separator (oxidizer gas separator)
8 Refrigerant separator (cooling medium separator)
10 Hydrogen channel (fuel gas channel)
11 Air channel (oxidant gas channel)
12 Refrigerant flow path (cooling medium flow path)
13 Refrigerant internal introduction manifold (cooling medium introduction manifold)
14 Refrigerant internal discharge manifold 24, 25 Movable part (dividing means)
39, 40 Flow control valve (cooling medium flow control means)
43, 44, 45, 46 Temperature sensor (temperature detection means)
47, 48 Humidity sensor (humidity detection means)
100 controller

Claims (6)

An oxidant gas separator having an oxidant gas flow path through which the oxidant gas flows;
A fuel gas separator having a fuel gas flow path through which the fuel gas flows;
An electrolyte membrane sandwiched between the oxidant gas separator and the fuel gas separator;
Cooling medium having a cooling medium flow path arranged so that a cooling medium for cooling a unit cell composed of the oxidant gas separator, the fuel gas separator, and the electrolyte membrane flows and intersects the flow direction of the oxidant gas A media separator;
In a fuel cell system having a fuel cell comprising: a cooling medium introduction manifold that communicates with the cooling medium flow path and introduces the cooling medium into the cooling medium flow path;
A dividing unit that divides the inside of the cooling medium introduction manifold in a direction intersecting the flow direction of the oxidant gas, and that is movable in the cooling medium introduction manifold based on an operating state of the fuel cell;
And a cooling medium flow rate control means for controlling the flow rate of the cooling refrigerant introduced into the cooling medium introduction manifold divided by the dividing means based on the operating state of the fuel cell. . Comprising temperature detecting means for detecting the temperature of the unit cell;
The dividing means moves in the cooling medium introduction manifold based on the temperature of the unit cell detected by the temperature detecting means,
The cooling medium flow rate control unit controls the flow rate of the cooling medium introduced into the divided cooling medium introduction manifold based on the temperature of the unit cell detected by the temperature detection unit. The fuel cell system described. The temperature detecting means is provided upstream and downstream of the divided cooling medium introduction manifold, detects the temperature of the cooling medium,
The dividing means moves in the cooling medium introduction manifold based on the temperature difference detected by the temperature detecting means,
3. The fuel cell system according to claim 2, wherein the cooling medium flow rate control unit controls the flow rate of the cooling medium introduced into the divided cooling medium introduction manifold based on the temperature difference. Comprising humidity detecting means for detecting the humidity of the oxidant gas;
The dividing means moves in the cooling medium introduction manifold based on the humidity of the oxidant gas detected by the humidity detecting means,
2. The cooling medium flow rate control means controls the flow rate of the cooling medium introduced into the divided cooling medium introduction manifold based on the humidity of the oxidant gas detected by the humidity detection means. 4. The fuel cell system according to any one of items 1 to 3. As the humidity of the oxidant gas decreases, the dividing means moves the region of the cooling medium introduction manifold upstream of the oxidant gas passage from the region of the cooling medium introduction manifold downstream of the oxidant gas passage. Wider than the area,
As the humidity of the oxidant gas decreases, the coolant flow rate control means causes the coolant flowing through the coolant flow path communicating with the coolant supply manifold upstream of the oxidant gas flow path to 5. The fuel cell system according to claim 4, wherein the flow rate of the cooling medium flowing through the cooling medium flow path communicating with the cooling medium introduction manifold on the downstream side of the oxidant gas flow path is increased. When the fuel cell is stopped, the dividing means makes the region of the cooling medium introduction manifold upstream of the oxidant gas flow path narrower than the area of the cooling medium introduction manifold downstream of the oxidant gas flow path. ,
When the fuel cell is stopped, the coolant flow rate control means is configured such that the coolant flowing through the coolant flow path communicating with the coolant supply manifold on the upstream side of the oxidant gas flow path is the oxidant gas flow path. 6. The fuel cell system according to claim 1, wherein a flow rate of the cooling medium flowing through the cooling medium flow path communicating with the cooling medium introduction manifold on the downstream side of the cooling medium is smaller.

Images