JP2005197133A - Cooling gas supply device of fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling gas supply device of a fuel cell, whereby stability and efficiency of power generation are enhanced by adjusting heat dissipation of an end part side cell positioned at the end part of a fuel cell stack, in order to thereby suppress temperature variations of each cell composing a fuel cell stack. <P>SOLUTION: A hinge part 120 made of a bimetal the bend angle of which varies in response to temperatures is connected to an end part side cell 14 E so as to keep free thermal conduction, and the bend angle of the hinge part 120 is varied in response to the temperature of the end part side cell 14E. Therefore, a degree of closing (degree of releasing) of the cooling gas passage 14a1 of the end part side cell 14E by the cooling gas passage closing plate 122 is adjusted by displacing the cooling gas passage closing plate 122 connected to the hinge part 120. That is, the flow of a cooling gas supplied to the end part side cell 14 is adjusted in response to the temperature of the end part side cell 14E to adjust heat dissipation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cooling gas supply device for a fuel cell.

  Conventionally, in order to improve the power generation efficiency of the fuel cell stack, it is widely performed to supply a cooling gas such as air and maintain the temperature at a desired value. However, since the plurality of single cells constituting the fuel cell stack vary in heat dissipation depending on their stacking positions, it is difficult to maintain the entire stack at a uniform temperature. Specifically, the unit cell located near the center of the fuel cell stack is dissipated only by the cooling gas, but the unit cell located on the end side of the fuel cell stack (end side unit cell) is in addition to that end. Since natural heat is radiated through the plate, there is a problem that when the cooling gas is uniformly supplied to each unit cell, the end-side unit cell is overcooled.

  Therefore, for example, in the technique described in Patent Document 1, a flow straightening direction of the cooling gas is provided by providing a rectifying means including a balloon in the intake manifold or the exhaust manifold of the cooling gas, and adjusting the degree of expansion of the balloon. By changing the speed, the flow rate of the cooling gas supplied to the end unit cell is reduced more than that near the center (that is, the heat dissipation of the end unit cell is suppressed). .

In Patent Document 1, the cooling gas is heated by a burner at the start-up when the temperature of the fuel cell is lowered, and the degree of expansion of the balloon is adjusted and supplied to the end-side cell. It has also been proposed to increase the temperature of the end-side cell by increasing the flow rate of the cooling gas after overheating more than that near the center.
JP-A-6-325786 (paragraphs 0012 to 0015, etc.)

  Depending on the operating environment (current density) of the fuel cell stack and the external environment such as the outside air temperature, the temperature of the end-side cell may rise as well as that near the center. For this reason, it is desirable that heat dissipation can be promoted with respect to the end-side cell.

  However, in the above-mentioned Patent Document 1, the cooling gas flow rate supplied to the end side unit cell is reduced to suppress heat dissipation, or the supply amount of the heated cooling gas is increased to promote the temperature rise. Nothing has been considered about promoting heat dissipation when the temperature of the end-side cell rises. For this reason, the temperature of each single cell varies depending on the operating state of the fuel cell and the external environment, and there is a problem that the stability and efficiency of power generation are reduced.

  Accordingly, the object of the present invention is to solve the above-mentioned problems, and to adjust the heat radiation according to the temperature of the end-side unit cell located at the end of the fuel cell stack, so that each unit cell constituting the fuel cell stack An object of the present invention is to provide a fuel cell cooling gas supply device that improves the stability and efficiency of power generation by suppressing temperature variations.

  In order to solve the above-described problem, in claim 1, in a cooling gas supply device for a fuel cell that supplies a cooling gas to cooling gas passages formed in a plurality of single cells constituting a fuel cell stack. And a cooling gas channel closing means for closing a cooling gas channel formed in the end side unit cell according to the temperature of the end side unit cell located on the end side of the fuel cell stack. did.

  Further, in the present invention, the cooling gas flow path closing means is connected to the end-side cell so as to be capable of conducting heat, and the bending angle changes according to the temperature of the end-side cell. And a cooling gas flow path closing plate that is connected to the hinge part and closes the cooling gas flow path formed in the end-side cell according to the bending angle of the hinge part. Configured.

  According to a third aspect of the present invention, the cooling gas flow path closing means is connected to the end unit cell so as to be capable of conducting heat, and stores when the temperature of the end unit cell is equal to or higher than the transformation point. A hinge portion made of a shape memory alloy that is deformed to a bending angle; an urging means that defines a bending angle of the hinge portion when the temperature of the end-side cell is below the transformation point; and the hinge portion. And a cooling gas flow path closing plate for closing the cooling gas flow path formed in the end unit cell by being displaced according to the bending angle of the hinge portion.

  The fuel cell cooling gas supply device for supplying a cooling gas to a cooling gas flow path formed in a plurality of single cells constituting the fuel cell stack according to claim 1, wherein the fuel cell stack has an end side. In accordance with the temperature of the end-side unit cell located at the end-side unit cell, a cooling gas channel closing means for closing the cooling gas channel formed in the end-side unit cell is provided. The heat radiation can be adjusted according to the temperature, and thus the temperature variation of each unit cell constituting the fuel cell stack can be suppressed to improve the stability and efficiency of power generation.

  Further, in the present invention, the cooling gas flow path closing means is connected to the end-side cell so as to be capable of conducting heat, and the bending angle changes according to the temperature of the end-side cell. And a cooling gas flow path closing plate that is connected to the hinge part and closes the cooling gas flow path formed in the end-side cell according to the bending angle of the hinge part. Since it comprised, in addition to the effect described in Claim 1, an apparatus can be simplified.

  According to a third aspect of the present invention, the cooling gas flow path closing means is connected to the end unit cell so as to be capable of conducting heat, and stores when the temperature of the end unit cell is equal to or higher than the transformation point. A hinge portion made of a shape memory alloy that is deformed to a bending angle; an urging means that defines a bending angle of the hinge portion when the temperature of the end-side cell is below the transformation point; and the hinge portion. The cooling gas flow path closing plate for closing the cooling gas flow path formed in the end-side unit cell by being displaced according to the bending angle of the hinge portion, is described in claim 1. In addition to the advantageous effects, the apparatus can be simplified.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a fuel cell cooling gas supply device according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing a fuel cell cooling gas supply device according to a first embodiment of the present invention as a part of a fuel cell unit.

  In FIG. 1, reference numeral 10 denotes a power generation unit including the fuel cell cooling gas supply device according to the first embodiment. The power generation unit 10 is formed by packaging elements necessary for power generation, such as a fuel cell stack 12 (hereinafter simply referred to as “stack”) and piping, in a portable size.

  The stack 12 is formed by laminating a plurality of, specifically 70, cells (cells) 14 and generates a rated output of 1.05 kw. The unit cell 14 includes an electrolyte membrane (solid polymer membrane), a cathode electrode (air electrode) and an anode electrode (fuel electrode) provided on both surfaces of the electrolyte membrane, and a separator disposed outside each electrode. This is a known polymer electrolyte fuel cell, and detailed description thereof is omitted.

  An air blower 20 that supplies cooling gas and cathode gas to the stack 12 is connected to the stack 12 via an intake manifold 22. Note that air is used as both the cooling gas and the cathode gas.

  The stack 12 is connected to an anode gas supply system 30 that supplies an anode gas (hydrogen gas) to the anode electrode. The anode gas supply system 30 includes an anode gas cylinder 32 in which hydrogen gas is sealed at a high pressure, pipes 34a to 34d that connect the anode gas cylinder 32 to the stack 12, and respective elements that will be described later disposed in the middle thereof.

  The anode gas cylinder 32 is connected to a regulator 38 via a manual cylinder valve 36, and the regulator 38 is connected to an ejector 40 via a first pipe line 34a. A main valve 42 (manual valve) is disposed in the middle of the first pipe line 34a. In addition, a second conduit 34b that bypasses the main valve 42 is connected to the first conduit 34a, and a first electromagnetic valve 44 and a second electromagnetic valve are provided in the middle of the second conduit 34b. 46 is arranged.

  The ejector 40 is connected to the inlet side of the anode electrode through the third pipe line 34c, and is connected to the outlet side of the anode electrode through the fourth pipe line 34d.

  Further, a purge gas supply system 50 that supplies a purge gas (inert gas, for example, nitrogen gas) to the stack 12 is connected downstream of the main valve 42 in the first pipe line 34a. The purge gas supply system 50 includes a purge gas cylinder 52 filled with purge gas at a high pressure, a fifth pipe 54 that connects the purge gas cylinder 52 to the first pipe 34a, and elements that will be described later disposed in the middle of the purge gas cylinder 52. Consists of.

  The purge gas cylinder 52 is connected to a regulator 58 via a manual cylinder valve 56, and the regulator 58 is connected to the first pipe line 34 a via a fifth pipe line 54. A third electromagnetic valve 60 is disposed in the middle of the fifth pipeline 54.

  A purge gas discharge system 70 is connected to the ejector 40 described above. The purge gas discharge system 70 includes a purge gas discharge path 72 connected to the ejector 40 and a fourth electromagnetic valve 74 arranged in the middle of the purge gas discharge path 72.

  An output circuit 80 is connected to the output terminal of the stack 12. The output circuit 80 is connected to an external device (not shown) via a first DC-DC converter 82 and a relay 84, and is connected to an ECU 88 (electronic control unit) via a second DC-DC converter 86. . The ECU 88 is connected to an operation switch 90 that can be turned on and off from the outside and the relay 84 described above.

  Next, the power generation operation of the stack 12 will be described based on the above configuration.

  The high-pressure anode gas sealed in the anode gas cylinder 32 is supplied to the regulator 38 when the cylinder valve 36 is manually opened. The anode gas depressurized and regulated by the regulator 38 is supplied to the ejector 40 through the first pipe 34a when the main valve 42 is manually operated (opened), and further the third pipe 34c. To the anode electrode of the stack 12. The first to fourth electromagnetic valves 44, 46, 60, 74 shown in FIG. 1 prevent the anode gas and the purge gas from flowing out when the stack 12 is not in operation. All valves are closed. In other words, the first to fourth electromagnetic valves 44, 46, 60, and 74 are all normal / close type electromagnetic valves (electromagnetic valves that close when not energized and open when energized).

  In each unit cell 14 of the stack 12, the anode gas supplied to the anode electrode generates an electrochemical reaction with the cathode gas existing in the cathode electrode, thereby starting power generation. Of the anode gas supplied to the anode electrode, the unreacted gas that has not been subjected to the electrochemical reaction with the cathode gas is returned to the ejector 40 via the fourth pipe 34d, and the third pipe It is supplied again to the anode electrode through 34c.

  When the power generation of the stack 12 is started, the electric power is converted into a DC voltage of an appropriate magnitude by the second DC-DC converter 86 provided in the output circuit 80, and then supplied to the ECU 88 as an operating power source. .

  The ECU 88 activated upon receiving the supply of electric power opens the first electromagnetic valve 44 and the second electromagnetic valve 46 and supplies the anode gas to the anode electrode through the second pipe 34b. The air blower 20 is operated.

  The air sucked by the air blower 20 is supplied to each single cell 14 through the intake manifold 22 as cooling gas or cathode gas. Further, the cooling gas and the cathode gas that have passed through each unit cell 14 are discharged to the outside of the stack 12 through the exhaust manifold 100 attached to the stack 12.

  When the ECU 88 is activated and the first electromagnetic valve 44 and the second electromagnetic valve 46 are opened, there is no need to manually operate the main valve 42. For this reason, the ECU 88 uses appropriate notification means (not shown) such as a voice or a display to indicate that the power generation of the stack 12 is started and the ECU 88 is activated, in other words, that the power supply to the external device is ready. Z) to the operator.

  When the operation switch 90 is manually operated (turned on) by an operator who knows that the power supply to the external device is ready, the ECU 88 operates the relay 84 provided in the output circuit 80. The first DC-DC converter 82 is electrically connected to an external device. As a result, the electric power generated by the stack 12 is converted into a direct current voltage having an appropriate magnitude by the first DC-DC converter 82 and then supplied to an external device via the relay 84.

  The ECU 88 also purges the stack 12 by operating each electromagnetic valve based on the output of a voltage sensor not shown. Specifically, when the detection value of the voltage sensor falls below a predetermined value, the first electromagnetic valve 44 and the second electromagnetic valve 46 arranged in the second pipe line 34b are closed, and the fifth The third electromagnetic valve 60 arranged in the pipe line 54 and the fourth electromagnetic valve 74 arranged in the purge gas discharge path 72 are opened.

  As a result, the supply of the anode gas is shut off, while the high-pressure purge gas sealed in the purge gas cylinder 52 is supplied to the regulator 58 through the cylinder valve 56, where the pressure is reduced and regulated, and then the fifth pipe 54 , And supplied to the anode electrode of the stack 12 via the ejector 40 and the third conduit 34c. The cylinder valve 56 is assumed to be opened in advance by the operator at the start of operation of the stack 12.

  The purge gas supplied to the anode electrode pushes out the unreacted gas and generated water staying in the anode electrode from the inside of the stack 12, and the outside of the stack 12 through the fourth pipe 34d, the ejector 40, and the purge gas discharge path 72. To be discharged.

  FIG. 2 is a perspective view of the stack 12 and the air blower 20 and intake manifold 22 connected thereto. FIG. 3 is a cross-sectional view of the stack 12.

  As shown in FIG. 2, the stack 12 is housed inside the case 110. An anode gas supply port 110b and an anode gas discharge port 110c are provided on the side surface 110a of the case 110 (more specifically, the side surface located on the extension line in the stacking direction of the stack 12). The anode gas supply port 110b is connected to the third pipeline 34c (not shown in FIG. 2) of the above-described anode gas supply system, while the anode gas discharge port 110c is connected to the fourth pipeline 34d ( (Not shown in FIG. 2) are connected.

  Further, two rectangular openings (indicated by reference numerals 110e and 110f) are formed on the side surface 110d of the case 110 (the side surface orthogonal to the side surface 110a), and their long sides are parallel to the stacking direction of the stack 12. It is drilled to become. Of the two openings, the upper opening indicated by reference numeral 110 e is a cooling gas supply port (hereinafter referred to as “cooling gas supply port”), and is connected to the anode separator 14 a (shown in FIG. 3) of each unit cell 14. The formed cooling gas flow path 14a1 (shown in FIG. 3) communicates with the inlet side. An opening denoted by reference numeral 110f is a cathode gas supply port (hereinafter referred to as “cathode gas supply port”), and is a cathode gas flow path (not shown) formed in the cathode separator 14b (shown in FIG. 3). It communicates with the entrance side. In FIG. 3, reference numeral 14c denotes an electrolyte membrane provided with an anode electrode and a cathode electrode.

  Further, the intake manifold 22 is attached to the side surface 110d. The intake manifold 22 includes a diameter-enlarged portion 22a that increases in diameter from the upstream side toward the downstream side, and a discharge port 22b is formed on the downstream side of the enlarged-diameter portion 22a. The discharge port 22b is formed to a size that covers the cooling gas supply port 110e and the cathode gas supply port 110f described above when the intake manifold 22 is attached to the side surface 110d of the case.

  An air blower 20 is connected to the upstream side of the enlarged diameter portion 22a of the intake manifold. The air blower 20 includes a scroll cover 20a, and a fan (not shown) fixed to the output shaft of the electric motor 20b is disposed therein. An air filter 20 c is attached to the air inlet of the air blower 20.

  Although not shown in the drawings, a cooling gas discharge port (hereinafter referred to as “cooling gas discharge port”) and a cathode gas discharge port (hereinafter referred to as “cathode gas discharge port”) are provided on the side surface of the case 110 facing the side surface 110d. ) And the exhaust manifold 100 is attached so as to cover the two openings.

  Further, as well shown in FIG. 3, the unit cells 14 located at both ends of the stack 12 are connected to the output terminal 12a. Each cell 14 and the output terminal 12a are sandwiched by the end plate 12c via the insulating plate 12b. The output terminal 12a, the insulating plate 12b, and the end plate 12c are all formed from a material having high thermal conductivity.

  Moreover, the hinge part 120 is attached between the insulating plate 12b and the end plate 12c.

  FIG. 4 is a perspective view showing the end plate 12 c, the hinge part 120, and the cooling gas flow path closing plate 122.

  As shown in FIGS. 3 and 4, a recess is formed on the side surface of the end plate 12 c in contact with the insulating plate 12 b, and one end of the hinge part 120 is fixed to the recess by a plurality (two) of bolts 124. A cooling gas flow path closing plate 122 is fixed to the other end of the hinge part 120 by a plurality (two) of bolts 126.

  Here, the hinge part 120 is made of bimetal obtained by laminating two types of metal plates having different thermal expansion coefficients, and is formed so that the cold shape is bent toward the unit cell 14 as shown in the figure. Further, the hinge portion 120 has a metal plate having a larger thermal expansion coefficient in contact with the insulating plate 12b (that is, located on the unit cell 14 side) and a metal plate having a smaller thermal expansion coefficient in contact with the end plate 12c. Be placed. That is, the hinge part 120 is bent toward the unit cell 14 as shown in FIGS. 3 and 4 when cold, but as the temperature rises, the bending angle increases as shown by the imaginary line in FIG. Configured to be smaller.

  As described above, the hinge portion 120 is a single cell (indicated by reference numeral 14E) located on the end side of the stack 12 through the end plate 12c, the insulating plate 12b, and the output terminal 12a formed of a material having high thermal conductivity. (Hereinafter referred to as “end-side cell”) so as to be capable of conducting heat, the temperature depends on the temperature of the end-side cell 14E. In this specification, the “end-side cell 14E” specifically means a cell that is located in the vicinity of the end plate 12c and that is strongly influenced by natural heat radiation from the end plate 12c.

  Accordingly, when the temperature of the end-side unit cell 14E decreases, the hinge portion 120 is bent to the unit cell 14 side accordingly, and as shown in FIGS. 3 and 4, the cooling gas flow path closing plate 122 is moved to the end side. The cooling gas channel 14 a 1 of the end side unit cell 14 E is closed by the cooling gas channel closing plate 122 because it is positioned in the immediate vicinity of the unit cell 14 E.

  On the other hand, when the temperature of the end-side cell 14E rises, the bending angle of the hinge portion 120 decreases accordingly, and the cooling gas flow path closing plate 122 ends as shown in FIG. 5 (and the imaginary line in FIG. 2). Since it is displaced in the direction away from the unit side unit cell 14E, the cooling gas flow path 14a1 of the end unit unit cell 14E is opened.

  As described above, the cooling gas flow path 14a1 of the end-side unit cell 14E increases the degree of closing by the cooling gas flow-path closing plate 122 as the temperature of the end-side unit cell 14E decreases. As the temperature of the battery 14E rises, the degree of closing becomes smaller (the degree of opening becomes larger). In this embodiment, as the temperature of the end-side cell 14E falls below a predetermined temperature (for example, 40 degrees) with high power generation efficiency, the degree of closure increases and the predetermined temperature ( For example, the thermal expansion coefficients of the two types of metal plates constituting the hinge portion 120 were set so that the degree of the closing becomes smaller as the temperature rises above 40 degrees.

  Next, assuming the above, the flow of the cooling gas and the cathode gas will be described.

  As shown in FIG. 2, the air sucked by the air blower 20 is passed through the enlarged diameter portion 22a and the discharge port 22b of the intake manifold after the dust is removed by the air filter 20c, and supplied with the cooling gas supply port 110e and the cathode gas. It flows into the mouth 110f.

  The air flowing into the cathode gas supply port 110e is supplied as a cathode gas to the cathode gas flow path of each unit cell 14. The cathode gas supplied to the cathode gas flow path is discharged to the outside through the cathode gas discharge port and the exhaust manifold 100.

  Further, the air that has flowed into the cooling gas supply port 110e is supplied as a cooling gas to the cooling gas channel 14a1 of each unit cell 14. The cooling gas supplied to the cooling gas flow path 14a1 is heated by absorbing heat generated in each unit cell 14 by power generation, and then discharged to the outside through the cooling gas discharge port and the exhaust manifold 100. The

  Here, when the temperature of the end-side cell 14E is lower than the predetermined temperature, the cooling gas flow of the end-side cell 14E is caused by the cooling gas flow path closing plate 122 as shown in FIGS. Since the path 14a1 is closed, the flow rate of the cooling gas supplied to the end side unit cell 14E is reduced. Therefore, heat dissipation by the cooling gas of the end side unit cell 14E is suppressed more than that of the unit cell 14 located near the center of the stack 12. Thereby, the temperature of the end side unit cell 14E can be raised toward the predetermined temperature.

  On the other hand, when the temperature of the end-side cell 14E exceeds the predetermined temperature, the bending angle of the hinge portion 120 becomes small, and as shown in FIG. 5 (and the imaginary line in FIG. 2), the end-side cell 14E. Since the cooling gas flow path 14a1 is opened, the flow rate of the cooling gas supplied to the end side unit cell 14E is increased. Thereby, the heat radiation by the cooling gas of the end side unit cell 14E is promoted, and thus the temperature of the end side unit cell 14E can be lowered toward the predetermined temperature.

  As described above, in this embodiment, the bimetallic hinge 120 whose bending angle changes according to the temperature is connected to the end-side unit cell 14E so as to be thermally conductive, and the end-side unit cell 14E By changing the bending angle of the hinge part 120 according to the temperature, the cooling gas flow path closing plate 122 connected to the hinge part 120 is displaced, and thus the end side by the cooling gas flow path closing plate 122 is moved. The closing degree (opening degree) of the cooling gas flow path 14a1 of the unit cell 14E was adjusted.

  By configuring as described above, the flow rate of the cooling gas supplied to the end side unit cell 14E (flowing into the cooling gas flow path 14a1) is adjusted according to the temperature of the end side unit cell 14E. For example, the heat radiation can be adjusted according to the temperature of the end-side unit cell 14E, and thus each of the stack 12 including the end-side unit cell 14E that is strongly affected by the natural heat radiation from the end plate 12c. It is possible to improve the stability and efficiency of power generation by suppressing the temperature variation of the single cells 14 (specifically, maintaining each cell 14 at the predetermined temperature where the power generation efficiency is high).

  Further, since the cooling gas flow path closing plate 122 is displaced by the bimetallic hinge part 120 connected to the end side unit cell 14E so as to be capable of conducting heat, the above-described effects can be obtained with a simple configuration. .

  Next, a fuel cell cooling gas supply apparatus according to a second embodiment of the present invention will be described.

  6 and 7 are partial cross-sectional views of the stack 12 showing the fuel cell cooling gas supply device according to the second embodiment.

  In the second embodiment, the hinge portion is made of shape memory alloy instead of bimetal. A hinge portion according to the second embodiment is denoted by reference numeral 120a in FIGS. The shape memory alloy hinge 120a is memorized so that its shape recovers to a flat plate shape when its temperature exceeds the transformation point.

  Similarly to the first embodiment, the hinge portion 120a is connected to the end-side unit cell 14E through the end plate 12c, the insulating plate 12b, and the output terminal 12a formed of a material having high thermal conductivity so as to be capable of conducting heat. When the temperature (that is, the temperature of the end unit cell 14E) is lower than the transformation point (referred to as the above-mentioned predetermined temperature), the bending spring 130 is bent by the biasing force of the bias spring 130 as shown in FIG. Be made. That is, the cooling gas flow path 14a1 of the end side unit cell 14E is closed by the cooling gas flow path closing plate 122, and the flow rate of the cooling gas supplied to the cooling gas flow path 14a1 of the end side unit cell 14E is reduced. Therefore, the heat radiation of the end side unit cell 14E is suppressed. The bias spring 130 is specifically a tension coil spring, one end of which is fixed at an appropriate position of the case 110 and the other end is fixed to the hinge portion 120a. The biasing force of the bias spring 130 is set to be smaller than the shape recovery force of the hinge portion 120a.

  Therefore, when the temperature of the hinge part 120a exceeds the transformation point, the shape memorized against the biasing force of the bias spring 130 (that is, a flat plate shape with a zero bending angle) as shown in FIG. ) To reduce the bending angle. That is, the degree of closing of the cooling gas flow path 14a1 of the end side unit cell 14E by the cooling gas flow path closing plate 122 is reduced (the degree of opening is increased), and the cooling gas flow path 14a1 of the end side unit cell 14E is reduced. The flow rate of the cooling gas supplied to is increased, and thus heat dissipation of the end-side cell 14E is promoted.

  Since the remaining configuration is the same as that of the first embodiment, the description thereof is omitted.

  As described above, in the second embodiment, the shape memory alloy hinge portion 120a whose bending angle changes at the transformation point is connected to the end unit cell 14E so as to be capable of conducting heat, and the end portion side is connected. By changing the bending angle of the hinge part 120a according to the temperature of the unit cell 14E, the cooling gas flow path closing plate 122 connected to the hinge part 120a is displaced. The closing degree (opening degree) of the cooling gas flow path 14a1 of the end side unit cell 14E is adjusted.

  Thereby, similarly to the first embodiment, the flow rate of the cooling gas supplied to the end side unit cell 14E (flowing into the cooling gas flow path 14a1) is adjusted according to the temperature of the end side unit cell 14E. That is, the heat radiation can be adjusted according to the temperature of the end-side unit cell 14E, and thus each of the stack 12 including the end-side unit cell 14E that is strongly affected by the natural heat radiation from the end plate 12c. It is possible to improve the stability and efficiency of power generation by suppressing the temperature variation of the single cells 14 (specifically, maintaining each cell 14 at the predetermined temperature where the power generation efficiency is high).

  Further, the cooling gas flow path closing plate 122 is formed by a shape memory alloy hinge portion 120a connected to the end-side unit cell 14E so as to be thermally conductive, and a bias spring 130 that defines the shape of the hinge portion 120a when cold. Since it is made to displace, the above-described effect can be obtained with a simple configuration.

  As described above, in the first and second embodiments of the present invention, the cooling gas is supplied to the cooling gas passages (14a1) formed in the plurality of single cells (14) constituting the fuel cell stack (12). In the cooling gas supply device of the fuel cell for supplying the fuel cell, the end cell unit (14E) is formed according to the temperature of the end cell unit (14E) located on the end side of the fuel cell stack (12). The cooling gas flow path closing means (hinge portions 120, 120a, cooling gas flow path closing plate 122, bias spring 130) for closing the cooling gas flow path (14a1) is provided.

  Further, in the first embodiment, the cooling gas flow path closing means is connected to the end-side cell (14E) so as to be capable of conducting heat, and depends on the temperature of the end-side cell (14E). Bimetal hinge part (120) whose bending angle changes, and is connected to the hinge part (120), and is displaced according to the bending angle of the hinge part (120), so that the end-side cell (14E) And a cooling gas flow path closing plate (122) for closing the cooling gas flow path (14a1) formed in the above.

  Further, in the second embodiment, the cooling gas flow path closing means is connected to the end side unit cell (14E) so as to conduct heat freely, and the temperature of the end side unit cell (14E) is transformed. When the temperature is higher than the point, the hinge portion (120a) made of a shape memory alloy that is deformed to the memorized bending angle and the hinge portion (120a) when the temperature of the end-side cell (14E) is lower than the transformation point A biasing means (bias spring 130) for defining a bending angle is connected to the hinge part, and is displaced according to the bending angle of the hinge part (120a) to be formed in the end-side cell (14E). A cooling gas flow path closing plate (122) for closing the cooling gas flow path (14a1) is used.

  In the above, the cooling gas flow path closing plate 122 may be plate-shaped, or may be a net-like shape in which a plurality of holes are drilled to allow a predetermined amount of air to pass.

It is the schematic which shows the cooling gas supply apparatus of the fuel cell which concerns on 1st Example of this invention as a part of fuel cell unit. FIG. 2 is a perspective view of a stack, an air blower, and an intake manifold shown in FIG. 1. It is sectional drawing of the stack shown in FIG. FIG. 4 is a perspective view of an end plate, a hinge part, and a cooling gas flow path closing plate shown in FIG. 3. FIG. 4 is a cross-sectional view of the stack shown in FIG. 1, similar to FIG. It is a fragmentary sectional view of a stack showing a cooling gas supply device of a fuel cell concerning the 2nd example of this invention. FIG. 7 is a partial cross-sectional view of the stack similar to FIG. 6.

Explanation of symbols

12 stack (fuel cell stack)
14 unit cell 14E end side unit cell 14a1 cooling gas channel 120 (according to the first embodiment) hinge portion (cooling gas channel closing means)
120a Hinge part (cooling gas flow path closing means) (according to the second embodiment)
122 Cooling gas flow path closing plate (cooling gas flow path closing means)
130 Bias spring (biasing means, cooling gas flow path closing means)

Claims (3)

  In a fuel cell cooling gas supply device for supplying a cooling gas to a cooling gas flow path formed in a plurality of single cells constituting a fuel cell stack, an end side single cell located on an end side of the fuel cell stack A cooling gas supply device for a fuel cell, comprising: a cooling gas passage closing means for closing a cooling gas passage formed in the end-side unit cell according to the temperature of the end cell.   The cooling gas flow path closing means is connected to the end-side unit cell so as to be able to conduct heat and has a bimetal hinge portion whose bending angle changes according to the temperature of the end-side unit cell, and the hinge portion. 2. The fuel cell according to claim 1, further comprising a cooling gas passage closing plate that is connected and closes a cooling gas passage formed in the end-side unit cell in accordance with a bending angle of the hinge portion. Cooling gas supply device. The cooling gas flow path closing means is made of a shape memory alloy that is connected to the end unit cell so as to be able to conduct heat and deforms to a memorized bending angle when the temperature of the end unit cell is equal to or higher than the transformation point. A hinge part, biasing means for defining a bending angle of the hinge part when the temperature of the end-side cell is below the transformation point, and connected to the hinge part, and depending on the bending angle of the hinge part 2. The cooling gas supply device for a fuel cell according to claim 1, further comprising a cooling gas channel closing plate that displaces and closes the cooling gas channel formed in the end cell.

Images