JP2005129387A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure air venting in the piping by preventing the trapped air from reversing to the piping. <P>SOLUTION: The fuel cell 9 mounted under the floor of a vehicle 1 and a radiator 13 installed in a motor room 3 are connected by a cooling water supply piping 15 and a cooling water exhaust piping 17. An air storage space 33 is provided in the cooling water exhaust piping 17 in the vicinity of the exit of the fuel cell 9 and the air storage space 33 is connected to a tank 19 in the motor room 3 installed at the location higher than that. Furthermore, the air storage spaces 29, 31, and 35, 37 are respectively provided in the cooling water supply piping 15 in the vicinity of the exit of a cooling water circulation pump 21 and a first system component 23, and in the cooling water exhaust piping 17 in the vicinity of the exit of a second system component 25 and a heat exchanger 27. Then, these and the tank 19 are respectively independently connected by the air vent pipings 39, 41, 45, 47. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell system that circulates fluid through system components.

  In the fuel cell system, a humidifier for humidifying the fuel gas and the oxidant gas, a pipe for supplying humidified water to the humidifier, and a cooling water for removing excess heat in the fuel cell generated by power generation are supplied. A pipe or a pipe for supplying cooling water for removing heat from the auxiliary equipment is provided, and the liquid circulates through these pipes.

For example, in the following Patent Document 1, in the above-described piping, a relatively high portion of the piping portion before and after the piping is connected to a steam separator through a branch pipe in the vertical direction, and the atmosphere is released on the spot and vented. The technology is disclosed.
Japanese Patent Laid-Open No. 15-123805

  However, in the conventional fuel cell system as described above, even if the air is trapped in the air reservoir space in the steam separator, the air remains there, so the trapped air may return to the pipe.

  In view of the above, an object of the present invention is to ensure that the trapped air does not return to the pipe so that the air in the pipe is vented.

  The present invention circulates a liquid in a flow path in a system component such as a fuel cell, and stores an air in an upper portion near an outlet of a pipe connected to the flow path in the system component. The most important feature is that an air vent pipe is connected from the air reservoir space to a tank for storing a liquid provided at a position higher than the air reservoir space.

  According to the present invention, the air reservoir space for storing air is provided in the upper part near the outlet of the pipe connected to the flow path of the system component, so that even when a large number of air reservoir spaces cannot be installed, especially air is mixed. It is possible to efficiently trap the air mixed into the pipe when passing through system components that are easy to be used.

  The air reservoir space can also be used as an air reservoir space when an initial liquid is put into the pipe.

  Furthermore, since the air vent pipe is connected from the air reservoir space to the tank that stores liquid higher than the air reservoir space, air is pumped from the air reservoir space to the tank that stores liquid by the internal pressure of the pipe. Therefore, the air trapped in the air reservoir space can be quickly moved to the tank using the air vent pipe, the return of air to the pipe can be prevented, and the air vent in the pipe can be ensured. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an overall schematic diagram showing a fuel cell system according to an embodiment of the present invention. In this fuel cell system, a portion surrounded by a broken line A is disposed under the floor 1 of the vehicle, and a portion surrounded by a broken line B is disposed in a motor room 3 at the front of the vehicle. FIG. 2 is a simplified side cross-sectional view of such a vehicle, in which 5 is a front wheel and 7 is a rear wheel.

  As shown in FIG. 2, the fuel cell 9 is mounted on a subframe 11 provided under the floor 1, and other components surrounded by the broken line A are also mounted on the subframe 11.

  The fuel cell 9 and the radiator 13 installed at the front part in the motor room 3 are connected by a cooling water supply pipe 15 and a cooling water discharge pipe 17 as shown in FIG. In FIG. 2, the cooling water supply pipe 15 and the cooling water discharge pipe 17 are omitted.

  The cooling water supply pipe 15 includes, in order from the radiator 13 side, an open tank 19 that stores liquid cooling water, a cooling water circulation pump 21 that pumps the cooling water toward the fuel cell 9, and a first system component 23. Are provided respectively. Here, the tank 19 is installed in the motor room 3, and the cooling water circulation pump 21 and the first system component 23 are installed under the floor 1.

  On the other hand, the cooling water discharge pipe 17 is provided with a second system component 25 and a heat exchanger 27 in order from the fuel cell 9 side, and these are installed under the floor 1.

  The above-described first and second system components 23 and 25 may be, for example, filters, heat exchangers, valves, etc., and their types are not limited. The fuel cell 9, the cooling water circulation pump 21, and the heat exchanger 27 also constitute system components.

  Each of these system components includes a flow path through which cooling water flows.

  Air reservoir spaces 29 and 31 are provided in the upper part (the highest part) of the cooling water supply pipe 15 in the vicinity of the outlet of the cooling water circulation pump 21 and in the vicinity of the outlet of the first system component 23, respectively. Air reservoir spaces 33, 35, and 37 are also provided in the upper part (the highest part) of the cooling water discharge pipe 17 near the outlets of the fuel cell 9, the first system component 25, and the heat exchanger 27, respectively. .

  Note that the vicinity of the outlet described above means a pipe from the outlet of each system component to another system component downstream thereof, or when there is a branch path, to the branch path. For example, the vicinity of the outlet of the fuel cell 9 is the cooling water discharge pipe 17 between the fuel cell 9 and the second system component 25.

  From these air reservoir spaces 29, 31, 33, 35, 37 to the tank 19 for storing the liquid provided at a position higher than the air reservoir spaces 29, 31, 33, 35, 37 in the motor room 3. 39, 41, 43, 45 and 47 are connected independently.

  The air vent pipes 39, 41, 43, 45, and 47 described above are vehicle widths in the vehicle under floor 1 as shown in FIG. 2 and FIG. 3, which is a simplified schematic diagram corresponding to the CC cross section of FIG. In the space 51 below the center tunnel 49 provided in the center in the direction, it is arranged along the vehicle front-rear direction and connected to the tank 19 in the motor room 3 at the front of the vehicle. At this time, each air vent pipe 39, 41, 43, 45, 47 is composed of a flow path from the bottom toward the tank 19 toward the tank 19 from the air reservoir space 29, 31, 33, 35, 37. The spaces 29, 31, 33, 35, and 37 are connected to the tank 19 without any downhill.

  In the fuel cell system configured as described above, the cooling water discharged from the cooling water circulation pump 21 passes through the first system component 23 and is supplied to the fuel cell 9. At this time, the cooling water absorbs heat generated by the electrochemical reaction between the fuel gas and the oxidant gas inside the fuel cell 9 and becomes high temperature.

  The high-temperature coolant discharged from the fuel cell 9 passes through the second system component 25 and then exchanges heat with the low-temperature fluid in the heat exchanger 27. Thereafter, the cooling water enters the radiator 13 to release heat, and further, the air is released from the tank 19 and returned to the cooling water circulation pump 21 to repeat the cycle.

  Here, in particular, the fuel cell 9 and the heat exchanger 27 have a fine internal flow path and are a portion where air easily accumulates. However, this air is in the piping near the outlet of the fuel cell 9 and the heat exchanger 27. The air is stored in the air reservoir spaces 33 and 37 at the highest position.

  In addition, the air accumulated in the flow paths in the other cooling water circulation pump 21 and the first and second system components 23 and 25 is also the air reservoir space at the highest position in the piping near these outlets. 29, 31, and 35 respectively.

  As a result, the air can be efficiently vented from the piping in the vicinity of the outlet of the system components such as the fuel cell 9, and as a result, a sufficient amount of cooling water can be secured and the cooling efficiency is improved.

  Air trapped in the air reservoir spaces 29, 31, 33, 35, and 37 is connected to the air reservoir spaces 29, 31, 33, 35, and 37 independently of each other by the internal pressure of the piping. Ascending and moving up to the tank 19 through 39, 41, 43, 45, 47. Thereby, it is possible to prevent the air trapped in the air reservoir spaces 29, 31, 33, 35, and 37 from returning to the piping.

  Such air reservoir spaces 29, 31, 33, 35, and 37 are always connected to the tank 19 by the air vent pipes 39, 41, 43, 45, and 47, and thus always have an air vent function.

  Further, the air vent pipes 39, 41, 43, 45, 47 are constituted by flow paths from the air reservoir spaces 29, 31, 33, 35, 37 toward the tank 19 from the lower side to the upper side. , 31, 33, 35, 37 to the tank 19 without any downhill, the backflow of air to the pipes in the air vent pipes 39, 41, 43, 45, 47 can be reliably prevented.

  Furthermore, by providing the air reservoir spaces 29, 31, 33, 35, 37, the air in the cooling water supply pipe 15 and the cooling water discharge pipe 17 can be vented at the time of cooling water injection.

  Further, the air vent pipes 39, 41, 43, 45, and 47 are connected from the air reservoir spaces 29, 31, 33, 35, and 37 to the tank 19 even at an operating pressure lower than when the trapped air is pumped at a normal pipe internal pressure. The trapped air can be guided to the tank 19 without stagnation inside the air vent pipes 39, 41, 43, 45, and 47, and further air venting performance can be improved. This can contribute to further improvement in cooling efficiency.

  Further, since the plurality of air vent pipes 39, 41, 43, 45, 47 are connected to the tank 19 in an independent state without being joined together, the air vent pipes 39, 41, 43, 45, 47 are provided midway. There is no possibility that the air flows backward due to the pressure difference as in the case of merging, and the backflow of air can be reliably prevented.

  Further, even in a vehicle in which the fuel cell 9 is arranged at a portion where the height of the vehicle floor 1 is limited, the plurality of air vent pipes 39, 41, 43, 45, 47 are guided upward using the center tunnel 49. Therefore, the air in the cooling water supply pipe 15 and the cooling water discharge pipe 17 can be easily vented.

  As described above, according to the present embodiment, when the fuel cell system is mounted under the floor of the vehicle, the air reservoir spaces 29, 31 and 33, 35, 37 are provided in the cooling water supply pipe 15 and the cooling water discharge pipe 17. And air vent pipes 39, 41, 43, 45, 47 for connecting the air reservoir spaces 29, 31, 33, 35, 37 and the tank 19 in the motor room 3 to the space 51 of the center tunnel 49. By connecting the air reservoir spaces 29, 31, 33, 35, and 37 to the tank 19 without downhill, the cooling water supply pipe 15 and the cooling water discharge pipe 17 can be easily vented and effective. The amount of cooling water can be secured and the cooling efficiency can be obtained.

  In the present embodiment, the example in which the present invention is applied to the cooling water pipe (the cooling water supply pipe 15 and the cooling water discharge pipe 17) is shown. However, the present invention is not limited to this, and instead of the cooling water pipe, The present invention is also applicable to a pure water piping system that supplies pure water to the electrolyte membrane and a humidified water (pure water) piping system that includes a humidifying device that humidifies fuel gas and oxidant gas instead of the fuel cell 9.

  According to the present invention, the system component is at least one of a fuel cell, a humidifier, and a heat exchanger, which has a fine internal flow path through which liquid flows and generates air when the fuel cell is started. By providing an air reservoir space in the vicinity of the outlet of the pipe connected to the pipe, effective air venting can be performed.

  Since the above-described air vent pipe is configured with a flow path that is directed upward from the air reservoir space toward the tank, it is possible to effectively prevent the backflow of air in the air vent pipe, and even during liquid injection, Easy to vent. Further, even at an operating pressure lower than the normal pipe internal pressure, the air trapped in the air reservoir space can be discharged to the tank without stagnation in the air vent pipe, and the air vent performance can be improved.

  The above air reservoir space is provided for each of a plurality of system components, and the air vent pipes are connected independently corresponding to each of the air reservoir spaces. Therefore, when the air vent pipes are merged on the way, Backflow due to a possible pressure difference can be prevented.

  Since the fuel cell system is installed under the floor of the vehicle, the air vent pipe is installed in the space under the center tunnel provided on the vehicle floor, and the tank is installed in the motor room in front of the vehicle. It is possible to connect the air vent piping from the air reservoir space to the tank provided in the motor room without any downhill, and even if the height is limited, such as a vehicle equipped with a fuel cell system under the vehicle floor, the air vent in the piping can be removed. It can be done easily.

  In addition, the tank installed in the motor room can more reliably increase the height of the air reservoir space, and the operation of injecting liquid from the tank becomes easy.

1 is an overall schematic diagram showing a fuel cell system according to an embodiment of the present invention. FIG. 2 is a simplified side cross-sectional view of a vehicle on which the fuel cell system of FIG. 1 is mounted. FIG. 3 is a simplified schematic diagram corresponding to the CC cross section of FIG. 2.

Explanation of symbols

3 Motor room 9 Fuel cell (system components)
15 Cooling water supply piping (piping connected to the flow paths in the system components)
17 Cooling water discharge pipe (pipe connected to the flow path in the system components)
19 Tank 21 Cooling water circulation pump (system components)
23 First system component 25 Second system component 27 Heat exchanger (system component)
29, 31, 33, 35, 37 Air reservoir space 39, 41, 43, 45, 47 Air vent pipe 49 Center tunnel 51 Space under the center tunnel

Claims (5)

  The liquid is circulated through the flow paths in the system components including the fuel cell, and an air storage space for storing air is provided in the upper part near the outlet of the pipe connected to the flow paths in the system components. A fuel cell system, wherein an air vent pipe is connected from an air reservoir space to a tank for storing a liquid higher than the air reservoir space.   2. The fuel cell system according to claim 1, wherein the system component is at least one of a fuel cell, a humidifier, and a heat exchanger.   3. The fuel cell system according to claim 1, wherein the air vent pipe is configured by a flow path from a lower side to an upper side toward the tank from the air reservoir space. 4.   4. The fuel cell system according to claim 3, wherein the air reservoir spaces are respectively provided corresponding to a plurality of system components, and the air vent pipes connecting the air reservoir spaces and the tank are provided in the plurality of air reservoir spaces. A fuel cell system provided independently for each of the above.   The fuel cell system according to claim 3 or 4, wherein the system is mounted under a vehicle floor, the air vent pipe is installed in a space under a center tunnel provided on the vehicle floor surface, and the tank is installed in a motor room in front of the vehicle. A fuel cell system characterized by being installed.

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