JP2002042846A - Cooling/warming installation for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling/warming installation for a fuel cell improving the power generation efficiency in cooling in the start of the fuel cell for a vehicle. SOLUTION: This cooling/warming installation is provided with a thermal storage device 4 for insulating the heat of cooling water to a prescribed temperature or more and storing it in a cooling water circulation system for cooling the fuel cell in a stable operation. When the fuel cell is started at a low temperature, the supply of the cooling water from a heat exchanger 3 for cooling the fuel cell is made to stop, and a channel of the cooling water is changed over so as to supply heat insulated cooling water in the thermal storage device to the fuel cell. When the temperature of the fuel cell inside becomes a prescribed temperature or more, the channel of the cooling water is changed over so as to supply the cooling water cooled in the heat exchanger to the fuel cell so as to suppress the temperature rise in the fuel cell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling / warming-up facility for a fuel cell which is used in a generator for home use or a car and takes out electricity by utilizing a chemical reaction between hydrogen and oxygen.

[0002]

2. Description of the Related Art In recent years, attention has been paid to electric vehicles for environmental problems, that is, air pollution, and electric vehicles equipped with storage batteries have already entered the stage of practical use. However, battery-powered vehicles have difficulties in solving such problems as a relatively short mileage and a long charging time in relation to the storage capacity of the battery. The emergence of battery-powered vehicles is awaited.

[0003] When a mobile fuel cell, that is, a fuel cell is mounted on a vehicle, there is a case where a serious problem occurs that the problem is not so large in the stationary fuel cell. One of them is a problem when the fuel cell is started in a cold state. this is,
When a fuel cell is used as a vehicle power source, it is not always used at a high load from the start, and the fuel cell is
It has the characteristic that the ability to warm up by itself is small because the heat generated by power generation loss is small, and the characteristic that the power generation efficiency is extremely low when the temperature is lower than the specified temperature, so that sufficient power can be obtained immediately after starting. Is difficult to obtain. In particular, in the case of the polymer electrolyte fuel cell, the power generation efficiency, that is, the energy conversion efficiency is high, so that the self-warming function is extremely small.

[0004]

In the above-mentioned conventional fuel cell, when the fuel cell is started, particularly in a cold region, the reaction between hydrogen and oxygen does not take place actively due to the low temperature of the fuel cell. Fuel hydrogen was discharged, an enormous amount of time and heater power were required to generate sufficient power, and a complicated and high-temperature combustor had to be provided.

[0005] The present invention has been made in view of the above circumstances,
An object of the present invention is to provide a fuel cell cooling / warm-up facility that improves the power generation efficiency of a fuel cell for a vehicle particularly at the time of cold start.

[0006]

According to the present invention, there is provided a fuel cell cooling / warm-up facility described in each claim as means for solving the above-mentioned problems. Claim 1
The fuel cell cooling / warm-up equipment described in the above, keeps the cooling water at a predetermined temperature or higher in a cooling water circulation system for cooling the fuel cell,
Provided is a warm storage means for storing, when the fuel cell is started at a low temperature, the cooling water circulation system side for cooling is closed, and the heated cooling water stored in the warm storage means is supplied to the fuel cell, and the fuel cell is operated. The temperature is raised to improve the power generation efficiency at the time of start-up cooling. Since liquid such as cooling water has a large heat capacity, heating the fuel cell while heating it requires a large amount of time and energy. However, when cooling water that has become hot during normal operation is stored and used, the magnitude of its heat capacity can be an advantage. Therefore, a small amount of high-temperature cooling water required for warming up the fuel cell is sufficient, so that a special large physique for warming up is unnecessary.

In the cooling / warm-up equipment according to the second aspect, an air pump for supplying pressurized air to the fuel cell is cooled by a part of the cooling water used for cooling the fuel cell.
As a result, since a non-lubricated air pump is used for a fuel cell that requires clean air, heat generation due to mechanical loss is large, and in addition to loss such as compression loss, the discharge temperature of the air pump is reduced. Although it increases inevitably, cooling the air pump with a part of the cooling water can ensure the efficiency and life of the pump.

According to a third aspect of the present invention, the cooling / warm-up equipment is configured such that the cooling water after cooling the air pump returns to the cooling water circulation system through the outer periphery of the heat retaining storage means. This is because the cooling water used after cooling the air pump is generally higher than the temperature after cooling the fuel cell. Therefore,
By utilizing the cooling water after cooling the air pump for heating the warm storage means, the heat generated by the air pump can be used effectively for warming up the fuel cell.

According to a fourth aspect of the present invention, the cooling / warm-up equipment is capable of supplying a portion of the high-temperature cooling water stored in the heat-retaining storage means to the fuel cell even during steady operation of the fuel cell. Therefore, it is possible to cope with low-temperature operation when the outside air temperature is low. In the cooling / warm-up equipment according to the fifth aspect, the heat-retaining storage means is provided with a heat storage material for absorbing and releasing heat by sublimation and condensation, thereby further increasing the heat storage efficiency of the heat-retention storage means. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cooling / warm-up facility for a fuel cell according to an embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows an overall configuration of a fuel cell cooling / warm-up facility of the present invention. In the fuel cell 1, a separator 11 having a groove (not shown) serving as a flow path for hydrogen and an enzyme (air) is arranged so as to sandwich a solid polymer membrane having electrodes attached thereto. In addition, the polymer film and the electrode are 1
If the temperature is set to 00 ° C. or more, a serious loss is given to the function thereof. Therefore, a groove (not shown) for passing cooling water is formed in the separator 11. That is, the fuel cell 1 has a structure in which the polymer membrane and the electrode are cooled by flowing the cooling water to contact the separator 11.

A closed loop cooling water circulation system for cooling the fuel cell 1 is connected to the fuel cell 1. In the cooling water circulation system, a pump 2 for circulating cooling water, a heat exchanger 3 for exchanging heat with outside air to cool the cooling water, and a feature of the present invention are provided in front of the fuel cell 1. Is,
A heat storage device 4 as a heat-retaining storage means for keeping and storing the cooling water as hot water is provided. Further, in the cooling water circulation system, a throttle valve 5a is provided between the outlet side of the heat exchanger 3 and the pump 2 and a throttle valve 5b is provided between the outlet side of the heat storage chamber 41 of the heat storage device 4 and the pump 2. , And the heat storage room 4 of the heat storage device 4
Switching valves 6a, 6b on the inlet side and the outlet side
Is provided, the outlet side of the heat storage device 4 is connected to the inlet side of the heat exchanger 3, and the outlet side of the heat retaining chamber 41 of the heat storage device 4 is directly connected to the pump 2 without the heat exchanger 3 via a bypass. Is also connected.

That is, in the cooling water circulation system, the cooling water exiting the fuel cell 1 is supplied to the switching valve 6a, the heat storage device 4, and the switching valve 6.
b, a system returning to the fuel cell 1 via the heat exchanger 3, the throttle valve 5a and the pump 2, and a fuel cell from the fuel cell 1 via the switching valve 6a, the heat storage device 4, the switching valve 6b, the throttle valve 5b and the pump 2. 1 and another system path is formed.

Further, in the present invention, an air pump cooling system for cooling an air pump 7 for supplying pressurized air to the fuel cell 1 is provided. This air pump cooling system is provided as a bypass system for a cooling water circulation system,
After a part of the cooling water after cooling is bypassed, the air pump 7 is cooled and then returned to the cooling water circulation system. In the present embodiment, the above-described heat storage device 4 has a double structure, and is provided with a pipe 42 so as to flow so as to wrap around a room outside the heat insulation room 41. The air pump cooling system uses cooling water after cooling the air pump. Pipe 4 around heat storage device 4
2 to return to the cooling water circulation system. The switching valves 6 are also provided on the inlet side and the outlet side of the pipe 42 of the heat storage device 4 in the air pump cooling system.
c, 6d are provided.

In order to detect the internal temperature of the fuel cell 1, a temperature sensor 8 is provided at the outlet of the fuel cell 1 in the cooling water circulation system as temperature detecting means. The output of the temperature sensor 8 is sent to the control device 9, and the control signal is used to control the throttle valves 5a, 5b and the switching valves 6a, 6
b, 6c, 6d and the pump 2 are controlled. Thereby, the circulation path and amount of cooling water circulating in the fuel cell 1 can be controlled, and temperature management such as heating and cooling of the fuel cell 1 can be performed.

As a heat storage means, the heat storage device 4 includes:
For example, it is possible to provide a heat storage material such as sodium acetate which repeatedly absorbs and dissipates heat by sublimation and condensation.

Next, the operation of the fuel cell cooling / warm-up facility of the present invention will be described. When the engine is started at a low temperature, the throttle valve 5a is completely closed. Switching valves 6a to 6d
Is set to the position shown in FIG. Therefore,
In the cooling water circulation system, a system returning from the fuel cell 1 to the fuel cell 1 via the switching valve 6a, the heat storage device 4, the switching valve 6b, the throttle valve 5b, and the pump 2 is formed, and the cooling water circulation system is heated to about 80 ° C. during the previous operation. The cooling water retained and stored in the heat storage device 4 is circulated in the fuel cell 1 without being cooled by the heat exchanger 3. At this time, there is no supply of hydrogen and air to the fuel cell 1. The fuel cell 1 is efficiently heated.

When the temperature of the fuel cell 1 rises to a temperature at which power can be generated,
Supply hydrogen and air. Since the air pump generates heat by driving the air pump 7, the switching valves 6c and 6d are switched from the state shown in FIG. 1, and a part of the circulating cooling water is passed through the air pump cooling system to cool the air pump 7. By returning the cooling water after cooling the air pump to the cooling water circulation system through the pipe 42 around the heat storage device 4, the heat from the air pump 7 absorbed by the cooling water also contributes to the heating of the fuel cell 1.

Further, the temperature in the fuel cell 1 rises to 60
When the temperature reaches around ° C., the throttle valve 5a is gradually released and the throttle valve 5b is throttled, so that the cooling water circulation system passing through the heat exchanger 3 becomes conductive, and the cooling water is circulated while being cooled.
To prevent the temperature inside the fuel cell 1 from becoming higher than necessary,
The degree of throttle and the degree of opening of the throttle valves 5a and 5b are adjusted,
The flow rate of the cooling water through the heat exchanger 3 can be reduced to the amount required for cooling.

In such a fuel cell cooling / warm-up facility, if the amount of cooling water stored in the heat storage device is appropriately set, there is no need to newly provide a heating means such as a heater or a burner, and simple cooling can be performed. / Warm-up facilities can be realized.

As described above, in the fuel cell cooling / warming-up equipment of the present invention, when heating the cooling water by heating the cooling water, the heat capacity of the cooling water is large and the heating takes time. , And fuel cells require clean air, so we focused on using a non-lubricated air pump,
During steady operation, a small amount of the steam-heated cooling water is kept and stored in the cooling water circulation system, and immediately after startup, the cooling water cooling system is used as a closed loop, and the heated and stored cooling water is rapidly cooled by the fuel cell. By circulating through the inside of the fuel cell, the temperature inside the fuel cell is efficiently raised.

That is, since liquid such as cooling water has a large heat capacity, heating the fuel cell while heating it requires a large amount of time and energy. However, when cooling water that has become hot during normal operation is stored and used, the magnitude of its heat capacity can be an advantage, and a small amount of high-temperature cooling water required for warm-up is sufficient. No extra large equipment is required for the machine.

In addition, since the air pump involves a loss such as a compression loss and a mechanical loss, the discharge temperature necessarily rises. In particular, non-lubricated air pumps generate considerable heat due to mechanical loss. Therefore, in order to ensure the efficiency and life of the pump, cooling is usually performed by passing cooling water through the pump, and the cooling water used for cooling is generally higher than the temperature of the fuel cell after cooling. high. Therefore, by supplying the cooling water used for cooling the fuel cell for further cooling the air pump, the heat generated in the entire system can be effectively used for warming up the fuel cell.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a fuel cell cooling / warm-up facility according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fuel cell 3 ... Heat exchanger 4 ... Heat storage device 5a, 5b ... Throttle valve 6a, 6b, 6c, 6d ... Switching valve 7 ... Air pump 8 ... Temperature sensor 9 ... Control device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuo Inagaki 14 Iwatani, Shimowasumi-cho, Nishio-shi, Aichi Prefecture Inside the Japan Automobile Parts Research Institute, Inc. F term (reference) in the company 5H027 AA02 CC06 DD06 KK41 KK46 MM16

Claims (5)

[Claims] A fuel cell that uses pressurized air as an oxidant; a cooling water circulation system that heats or cools the fuel cell; and a heat exchanger that cools cooling water provided in the cooling water circulation system. Similarly, a heat-retention storage means provided in the cooling water circulation system for keeping and storing the cooling water at a predetermined temperature or higher, a flow switching means for switching a flow path of the cooling water of the cooling water circulation system, Temperature detection means for detecting an internal temperature, and control means for controlling the flow path switching means based on an output from the temperature detection means, wherein when the fuel cell is started at a low temperature, the fuel cell is cooled. The supply of the cooling water from the heat exchanger is stopped, and the flow path of the cooling water is supplied to the fuel cell while keeping the warmed cooling water kept in the warm storage means. Switch the fuel When the temperature inside the pond becomes equal to or higher than a predetermined temperature, the flow path is switched so that the cooling water cooled by the heat exchanger is supplied to the fuel cell, so as to suppress an increase in the temperature inside the fuel cell. A cooling / warm-up facility for a fuel cell, wherein the flow control means is controlled by the control means. 2. An air pump cooling system for using a part of cooling water used for cooling the fuel cell to cool an air pump for supplying pressurized air to the fuel cell. The fuel cell cooling / warm-up facility according to claim 1. 3. The air pump cooling system is connected to the cooling water circulation system such that the cooling water after cooling the air pump enters the heat exchanger through the outer periphery of the heat retaining storage means. The fuel cell cooling / warm-up facility according to claim 2. 4. Even during a steady operation of the fuel cell,
When the outside air temperature is low and the output is low, the control means controls the flow path switching means so that a part of the high-temperature cooling water stored in the heat retaining storage means is supplied to the fuel cell without cooling. The fuel cell cooling / warm-up facility according to any one of claims 1 to 3, wherein: 5. The fuel cell according to claim 1, wherein the thermal storage means has a heat storage material that absorbs and releases heat by sublimation and condensation. Cooling / warm-up equipment.