JP2007242326A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of removing water from a water supply system more rapidly and certainly when discharging the water in the water supply system connected to a water tank to the outside. <P>SOLUTION: A drain valve 12 is installed in a water supply system 11 connected to a water tank 8, and a tank internal pressure increasing means 100 which raises the internal pressure of the water tank 8 when discharging the water from the drain valve 12 is installed. Thereby, by removing rapidly and certainly the water in the water supply system 11 by the increased pressure in the water tank from the drain valve 12, freezing of the water supply system 11 during system stoppage in a cold district is prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell system, and more particularly, to a fuel cell system including a water tank for storing water to be supplied to the fuel cell.

  A fuel cell system that removes the heat generated by the fuel cell using the latent heat of vaporization of water is equipped with a water tank for storing water for that purpose, and thus a fuel equipped with a fuel cell system equipped with a water storage tank. In a battery car, water in a water tank and a water supply system connected to the water tank may freeze in a cold region, and in such a case, the startability of the fuel cell system deteriorates.

For this reason, a fuel cell system has been proposed in which the water in the water tank is heated using the heat of the exhaust air of the fuel cell (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2003-31243 (5th page, FIG. 2)

  However, in such a conventional fuel cell system, even if the water in the water tank is heated, the water is only heated using the heat generated by the fuel cell after the system is started. The water existing (remaining) in the water tank and the water supply system connected to the water tank is frozen inside, and the smooth operability of the system is deteriorated.

  For this reason, by discharging the water in the water supply system connected to the water tank outside the system when the system is stopped, water can be prevented from freezing in the water supply system during the system stop, and By supplying new water to the water supply system after starting the system, the system can be operated smoothly after starting.

  Accordingly, the present invention provides a fuel cell system in which when water in a water supply system connected to a water tank is discharged out of the system, water can be quickly and reliably removed from the water supply system. It is.

  The present invention is connected to the water tank in a fuel cell system in which water stored in the water tank is supplied to the fuel cell, and heat generated by power generation of the fuel cell is removed by the latent heat of vaporization of the water and removed. The main feature is that a drainage means is provided in the water supply system, and a tank internal pressure raising means for increasing the internal pressure of the water tank when draining water from the drainage means.

  According to the present invention, when the water in the water supply system is drained, the internal pressure of the water tank can be increased by the tank internal pressure increasing means, so that the water in the water supply system is drained by the increased pressure in the water tank. Can be extruded efficiently. For this reason, when it is necessary to drain water to prevent freezing when the system is stopped, the water in the water supply system is more quickly and reliably removed by the tank internal pressure increasing means. The water supply system can be prevented from freezing while the system is stopped in a cold region. As a result, according to the present invention, it becomes possible to prevent the blockage of the path and the breakage of the pipe due to the water freezing.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

[Embodiment 1]
1 and 2 show Embodiment 1 of a fuel cell system according to the present invention, FIG. 1 is an overall schematic configuration diagram of a fuel cell system mounted on a vehicle, and FIG. 2 is a schematic configuration diagram showing an essential part of the fuel cell system. It is.

  The fuel cell system FC of this embodiment is shown as an example when mounted on a vehicle M as shown in FIG. 1, and includes a fuel cell 1, a fuel supply means for supplying hydrogen as fuel to the fuel cell 1, a fuel An oxidant supply means for supplying air as an oxidant to the battery 1 and a water supply means for removing heat generated by power generation by latent heat of vaporization and cooling are provided as main components, and the fuel cell 1 is supplied with hydrogen and air. By supplying each, the hydrogen and oxygen in the air are reacted electrochemically to obtain generated power.

  The fuel cell 1 includes a membrane electrode assembly (MEA) formed by sandwiching an electrolyte membrane between an anode side electrode (fuel electrode) and a cathode side electrode (oxidant electrode), and both sides of the membrane electrode assembly. The fuel cell system FC according to this embodiment includes a cell stack formed by stacking a plurality of unit fuel cells (single cells) in which separators having flow paths for supplying hydrogen, air, and water are arranged. In addition, the separator is formed as a porous body, water is leached into the electrolyte membrane, and heat generated by power generation is removed by the vaporization latent heat of the water.

  The fuel supply means includes, for example, a high-pressure hydrogen tank that stores hydrogen, a hydrogen supply pipe, a valve, a hydrogen exhaust pipe, a hydrogen dilution device, a hydrogen combustion device (all of which are not shown), and the like. The hydrogen taken out from the high-pressure hydrogen tank is supplied to the fuel electrode of the fuel cell 1 through the hydrogen supply pipe after the flow rate and pressure are adjusted by a variable valve or the like. The anode exhaust gas discharged from the fuel electrode of the fuel cell 1 passes through the hydrogen exhaust pipe, and the hydrogen concentration is sufficiently diluted by the hydrogen dilution device or burned by the hydrogen combustion device and oxidized, and then the system It is discharged outside.

  The oxidant supply means includes, for example, a compressor (compressor) 2 that compresses air and supplies it to the oxidant electrode of the fuel cell 1, an air supply pipe 3 that sends the compressed air to the fuel cell 1, and sets the air to a predetermined humidity. A humidifier 4, an air cooling device (condenser) 5 that lowers the temperature of air exhausted from the fuel cell 1, a gas-liquid separator (separator) 6 that separates water contained in exhaust air condensed by the capacitor 5, and the like. .

  The air compressed and supplied by the compressor 2 is adjusted in flow rate and pressure by a variable valve or the like, adjusted to an appropriate temperature / humidity by the humidifier 4, and supplied to the oxidant electrode of the fuel cell 1, The exhausted air discharged from the oxidant electrode of the fuel cell 1 is sent to the condenser 5 from the upstream air exhaust pipe 7A and cooled, and then gas-liquid separated by the gas-liquid separator 6 to be downstream. Is discharged to the outside of the system via the air exhaust pipe 7B.

  The water supply means includes, for example, a water tank 8 for storing water, a water supply pipe 9 for supplying water from the water tank 8 to the fuel cell 1 (or the fuel cell 1 via the humidifier 4), and gas-liquid separation. And a pump 10 for returning the water separated by the vessel 6 to the water tank 8 again. In FIG. 1, water is directly supplied from the water tank 8 to the fuel cell 1 through the water supply pipe 9, but the humidifier 4 is disposed upstream of the fuel cell 1, and the fuel cell is passed through the humidifier 4. 1 may be supplied with water.

  Here, the fuel cell system FC of the present embodiment is provided with a drain valve 12 as a drain means in the water supply system 11 connected to the water tank 8 and drains water from the drain valve 12 as shown in FIG. The tank internal pressure raising means 100 for increasing the internal pressure of the water tank 8 is provided.

  The water supply system 11 includes the gas-liquid separator 6 that separates and stores the water condensed by the condenser 5, the pump 10 that pumps up the water in the gas-liquid separator 6, and water pumped by the pump 10. And a water supply pipe 13 for supplying water to the water tank 8.

  The drain valve 12 is provided in a drain pipe 14 that communicates with the bottom of the gas-liquid separator 6. By opening the drain valve 12, the water in the gas-liquid separator 6 is discharged from the system via the drain pipe 14. On the other hand, the water in the water supply pipe 13 and the water in the pump 10 are caused to flow back into the gas-liquid separator 6, and the backflowed water is simultaneously discharged from the drain pipe 14.

  As shown in FIG. 2, the tank internal pressure raising means 100 communicates an air exhaust system 15 that exhausts air from the fuel cell 1 and the water tank 8, and introduces air from the air exhaust system 15 into the water tank 8. The air intake path 101 is formed.

  The air exhaust system 15 includes the upstream air exhaust pipe 7 A communicating with the fuel cell 1, the condenser 5, the gas-liquid separator 6, and the downstream air exhaust communicating with the upper portion of the gas-liquid separator 6. The air intake passage 101 is provided to be branched from the upstream side air exhaust pipe 7A. A downstream pressure regulating valve 17 is provided in the downstream air exhaust pipe 7B.

  In the fuel cell 1, as shown in FIG. 2, a plurality of cells 23 in which an oxidant electrode (cathode side electrode), an electrolyte membrane 22, and a fuel electrode (anode side electrode) are arranged are stacked between opposed porous separators 21. A stack 20 is provided, and a manifold 24 is arranged on the side of the stack 20. The separator 21 has an air passage 25 formed on the surface facing the oxidant electrode and a hydrogen passage 26 formed on the surface facing the fuel electrode. In addition, water flow paths 27 through which water flows are formed on the opposing surfaces of the separators 21.

  In FIG. 1 and FIG. 2, the air intake path 101 communicating with the water tank 8 is provided in the air exhaust system 15, but the air intake system 16 that supplies air to the fuel cell 1 and the humidifier 4 is used. A path 101 may be provided. The air supply system 16 includes the compressor 2 and an air supply pipe 3 that supplies the compressed air of the compressor 2 to the fuel cell 1.

  Further, the tank internal pressure increasing means 100 increases the air amount of the air supply system 16 and the air exhaust system 15 in addition to the air intake passage 101 for introducing the air of the air exhaust system 15 into the water tank 8. The compressor 2 is used as an air increasing means.

  That is, by increasing the air discharge amount of the compressor 2, the amount of air passing through the air supply system 16 is increased, and the increased amount of air increases when surplus air also passes through the fuel cell 1. Thus, the amount of air passing through the air exhaust system 15 can also be increased, and consequently, the amount of air introduced into the water tank 8 via the air intake path 101 can be increased.

  With the above configuration, according to the fuel cell system FC of the present embodiment, the air intake passage 101 branched from the air exhaust pipe 7A is communicated with the water tank 8 to configure the in-tank raising means 100 and connected to the water tank 8. When the water in the water supply system 11 is drained, the internal pressure of the water tank 8 is increased by the in-tank raising means 100, so that the water supply pipe 13 of the water supply system 11 is increased by the increased pressure in the water tank 8. The water in the gas can be pushed back into the gas-liquid separator 6 efficiently, and the water in the gas-liquid separator 6 is opened from the drain pipe 14 to the outside of the system by opening the drain valve 12. It can be discharged.

  Therefore, when the fuel cell system FC is stopped or the like and water drainage is required, the pressure in the water tank 8 is increased so that the water can be quickly and reliably removed from the water supply system 11. It is possible to prevent the water supply system 11 from freezing while the system is stopped on the ground. For this reason, when the fuel cell system FC is subsequently started up, the system can be smoothly operated by supplying new water to the water supply system 11. It is also possible to avoid path blockage and piping damage due to water freezing.

  Further, in the fuel cell system FC of the present embodiment, when the water in the water supply system 11 can be discharged manually from the drain pipe 14 through the drain valve 12 to the outside of the system, the water tank 8 can be manually supplied with water. In addition, it can also serve as an overflow function that sets the amount of water in the water tank 8 to an appropriate water level.

  Further, the tank internal pressure raising means 100 is formed by an air intake passage 101 that communicates the air exhaust system 15 and the water tank 8 and introduces air from the air exhaust pipe 7A into the water tank 8. Since the tank internal pressure increasing means 100 can be configured by a simple structure in which the air exhaust system 15 and the water tank 8 are simply communicated with each other through the air intake passage 101, the water supply can be performed without causing a significant increase in cost. The water of the system 11 can be discharged.

  Furthermore, the tank internal pressure increasing means 100 uses the compressor 2 as an air increasing means so as to increase the amount of air in the air supply system 16 and the air exhaust system 15, and accordingly, the air introduced into the water tank 8 is increased. By increasing the amount, the pressure in the water tank 8 can be further increased, and the differential pressure between the water tank 8 and the water discharge portion, that is, the gas-liquid separator 6 in this embodiment, is increased. Water drainage can be improved.

[Embodiment 2]
FIG. 3 shows a second embodiment of the present invention, in which the same components as in the first embodiment are denoted by the same reference numerals and redundant description is omitted, and FIG. 3 is a schematic diagram showing the main part of the fuel cell system. It is a block diagram.

  The fuel cell system FC of the present embodiment has basically the same configuration as that of the first embodiment. As shown in FIG. 3, the air intake passage 101 branched from the air exhaust pipe 7A is communicated with the water tank 8 to exhaust air. A drain valve 12 is provided in a drain pipe 14 that introduces air of the system 15 into the water tank 8 and communicates with the bottom of the gas-liquid separator 6.

  In addition to the air intake path 101, the tank internal pressure increasing means 110 of the present embodiment is arranged on the downstream side of the air intake path 101 of the air exhaust system 15, and throttles and controls the air exhaust amount. Thus, an upstream side pressure regulating valve 111 is provided as pressure adjusting means for increasing the air pressure introduced into the air intake passage 101.

  The upstream pressure regulating valve 111 is provided in the air exhaust pipe 7 </ b> A of the air exhaust system 15 and is disposed between the branch portion 102 of the air intake path 101 and the condenser 5. Then, by adjusting the throttle amount of the upstream pressure regulating valve 111, the exhaust air pressure in the air exhaust pipe 7A on the upstream side of the upstream pressure regulating valve 111 can be increased, and as a result, from the air intake path 101. The air pressure supplied to the water tank 8 can be increased.

  With the above configuration, according to the fuel cell system FC of the present embodiment, the air intake path 101 branched from the air exhaust pipe 7A communicates with the water tank 8, and the drain valve 12 is provided at the bottom of the gas-liquid separator 6. Since the drain pipe 14 is connected, the same effect as that of the first embodiment can be obtained. In particular, in this embodiment, the tank internal pressure raising means 110 is added to the air intake passage 101 to provide air. Since the upstream side pressure regulating valve 111 is provided on the downstream side of the air intake path 101 of the exhaust pipe 7A, the upstream side pressure regulating valve 111 controls the exhaust amount of air to introduce it into the air intake path 101. Since the pressure in the water tank 8 can be increased by increasing the air pressure, the pressure difference between the water tank 8 and the gas-liquid separator 6 can be increased to improve the water drainage.

[Embodiment 3]
FIG. 4 shows a third embodiment of the present invention, in which the same components as those of the above-described embodiments are denoted by the same reference numerals and redundant description is omitted, and FIG. 4 is a schematic diagram showing the main part of the fuel cell system. It is a block diagram.

  The fuel cell system FC of the present embodiment has basically the same configuration as that of the second embodiment, and communicates the air intake path 101 branched from the air exhaust pipe 7A to the water tank 8 as shown in FIG. A drain valve 12 is provided in the drain pipe 14 communicating with the bottom of the gas-liquid separator 6, and the upstream side pressure regulating valve 111 is provided between the branch portion 102 of the air intake path 101 of the air exhaust pipe 7 A and the condenser 5. Is provided.

  In the fuel cell system FC of the present embodiment, a large-capacity hollow portion 120 is provided in the outlet portion of the air exhaust system 15, that is, the downstream air exhaust pipe 7B, and the large-capacity hollow portion 120 is connected to the drain valve 12 from the drain valve 12. The drained water W is temporarily stored. The large-capacity hollow portion 120 is formed, for example, as a cylindrical body or rectangular body having an internal space with a large capacity such that the entire space is not filled with drainage with a stainless steel plate or the like.

  At this time, the large-capacity hollow portion 120 is arranged on the downstream side of the downstream pressure regulating valve 17 of the air exhaust pipe 7B, and downstream of the drain pipe 14 provided with the drain valve 12. The side communicates with the large-capacity hollow portion 120.

  Accordingly, the water W discharged from the drain pipe 14 flows into the large-capacity hollow portion 120, but after a predetermined amount of water flowing into the large-capacity hollow portion 120 is stored, the water W is discharged from the discharge pipe 121 to the outside of the system. Is discharged. At this time, the exhaust air A of the air exhaust pipe 7B is also exhausted from the exhaust pipe 121.

  In the present embodiment, the downstream side air exhaust pipe 7B, which is the air exhaust system 15, is provided with a downstream side pressure regulating valve 17 as pressure regulating means, and the downstream side pressure regulating valve 17 is provided downstream of the air exhaust pipe 7B. A drain pipe 14 for discharging water discharged from the drain valve 12 is connected.

  That is, in this embodiment, the outlet portion of the drain pipe 14 provided with the drain valve 12 is connected to the large-capacity hollow portion 120. By connecting the drain pipe 14 to the large-capacity hollow portion 120 in this way, The drain pipe 14 is connected to the downstream side of the downstream side pressure regulating valve 17 of the air exhaust pipe 7B.

  With the above configuration, according to the fuel cell system FC of the present embodiment, the air intake path 101 communicates with the water tank 8 and the drain pipe 14 provided with the drain valve 12 at the bottom of the gas-liquid separator 6 communicates. In addition, since the upstream side pressure regulating valve 111 is provided between the branch portion 102 of the air intake passage 101 of the air exhaust pipe 7A and the condenser 5, it goes without saying that the same effects as those of the second embodiment can be obtained. In particular, in the present embodiment, the water W drained from the drain valve 12 is temporarily stored in the large-capacity hollow portion 120 provided in the downstream air exhaust pipe 7B. The water W of the supply system 11 can be prevented from being discharged from the drain valve 12 to the outside of the vehicle at once. For example, in a parking lot or the like, the road surface is not flooded, so the commercial value as a vehicle is reduced. Avoid Rukoto can.

  In addition, even when water W is frozen in the large volume hollow portion 120, the frozen portion is a part of the cross section of the large volume hollow portion 120, and the passage space for the exhaust air A is always secured. Therefore, the exhaust air A can be prevented from being clogged when the system is started.

  And the water W frozen in the large capacity | capacitance hollow part 120 with a system operation | movement is thawed | decompressed gradually, and the thawed water W is discharge | released out of a vehicle with the exhaust air A, Since the vehicle is in a running state, there is almost no impact on the product value.

  Furthermore, in this embodiment, since the drain pipe 14 is connected to the air exhaust pipe 7B on the downstream side of the downstream pressure regulating valve 17, the pressure in the gas-liquid separator 6 is increased by restricting the downstream pressure regulating valve 17. Since the differential pressure with the exhaust air on the downstream side of the downstream side pressure regulating valve 17 of the air exhaust pipe 7B can be increased, the water in the gas-liquid separator 6 can be quickly and reliably removed from the drain pipe 14 (this embodiment) Then, it can discharge | emit into the large capacity | capacitance hollow part 120), and the drainage property of water can be improved.

  By the way, although the fuel cell system of the present invention has been described by taking the above embodiments as examples, the present invention is not limited to these embodiments, and various other embodiments can be adopted without departing from the gist of the present invention.

1 is an overall schematic configuration diagram of a fuel cell system mounted on a vehicle in Embodiment 1 of the present invention. It is a schematic block diagram which shows the principal part of the fuel cell system in Embodiment 1 of this invention. It is a schematic block diagram which shows the principal part of the fuel cell system in Embodiment 2 of this invention. It is a schematic block diagram which shows the principal part of the fuel cell system in Embodiment 3 of this invention.

Explanation of symbols

1 Fuel cell 2 Compressor (Air increase means)
4 Humidifier 8 Water tank 11 Water supply system 12 Drain valve (drainage means)
DESCRIPTION OF SYMBOLS 14 Drain pipe 15 Air exhaust system 16 Air supply system 100,110 Tank internal pressure raising means 101 Air intake path 111 Upstream pressure regulating valve (pressure regulating means)
120 Large-capacity hollow FC fuel cell system

Claims (6)

In the fuel cell system, the water stored in the water tank is supplied to the fuel cell, and the heat generated by the power generation of the fuel cell is taken away by the latent heat of vaporization of the water for cooling.
A fuel cell system comprising: a drainage means provided in a water supply system connected to the water tank; and a tank internal pressure increasing means for increasing the internal pressure of the water tank when draining water from the drainage means. The fuel cell system according to claim 1,
The tank internal pressure increasing means communicates an air supply system that supplies air to the fuel cell or humidifier, or an air exhaust system that discharges air from the fuel cell or humidifier, and the water tank, and these air supply system or air A fuel cell system, characterized by being an air intake path for introducing exhaust air into a water tank. The fuel cell system according to claim 2, wherein
The tank internal pressure increasing means includes an air increasing means for increasing the amount of air in the air supply system and the air exhaust system. A fuel cell system according to claim 2 or claim 3, wherein
The tank internal pressure increasing means is disposed downstream of the air intake path of the air exhaust system, and pressure adjusting means for increasing the air pressure introduced into the air intake path by restricting the air exhaust amount. A fuel cell system comprising: A fuel cell system according to any one of claims 1 to 4,
A fuel cell system characterized in that a large-capacity hollow portion is provided at an outlet portion of the air exhaust system, and water drained from the drainage means is temporarily stored in the large-capacity hollow portion. The fuel cell system according to claim 5, wherein
A fuel cell system, wherein a pressure adjusting means is provided in the air exhaust system, and a drain pipe for discharging water drained from the drain means is connected to the air exhaust system downstream of the pressure adjusting means.

Images