JP2000277135A - Heat insulating device of phosphoric acid type fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of parts of a heating appliance for heat insulation and power source capacity, to enhance maintenance property and to provide a low-cost phosphoric acid type fuel cell easily insulating heat compared with a conventional heat insulating device of a fuel cell. SOLUTION: In this phosphoric acid type fuel cell, a fuel cell body 1 is surrounded with a heat-insulating member 5a. A space part 20 where air can convect is provided between the fuel cell body 1 and the heat-insulating member 5a. A space heater 6 for heating the air in the space part 20 is disposed in the space part 20. In addition, in the fuel cell, an inspection door 7 for inspecting the space heater 6 is disposed near the space heater 6 of the heat-insulating member 5a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for keeping a phosphoric acid fuel cell warm while the fuel cell is stopped or transported.

[0002]

2. Description of the Related Art As is well known, a phosphoric acid type fuel cell holds phosphoric acid in an electrolyte layer and uses a fuel gas (for example, hydrogen) and an oxidant gas (for example, air) as a reaction gas as a fuel electrode and an oxidant. The energy is continuously supplied to the drug electrode, and the energy of the fuel is electrochemically converted into electric energy.

In the above-described phosphoric acid type fuel cell, phosphoric acid as an electrolyte freezes during the period when the operation of the battery is stopped, such as during construction or maintenance of the power generator or peripheral equipment, or during transportation of the power generator, and the volume of the fuel expands. In order to prevent accidents such as breakage of the porous matrix holding phosphoric acid, freezing of phosphoric acid is prevented by the following method.

(1) A method in which an electric heater is provided on the upper and lower fastening members and the manifold of the fuel cell stack, and the temperature is kept by an external power source to prevent the temperature of the fuel cell stack from lowering. FIG.
Fig. 1 shows an example of a conventional fuel cell heat retention device for implementing this method. The fuel cell stack 1 includes an upper clamp plate 3a, a lower clamp plate 3b, and a manifold 4 for reactant gas. The fuel cell body 1 is surrounded by a heat insulating member 5a. 14
Shows the electric heater for keeping heat.

(2) A method of heating and circulating fuel cell cooling water to prevent the temperature of the fuel cell stack from lowering. A boiler, pump, etc. of a power generator are used for heating and circulation of cooling water.

(3) A method in which phosphoric acid is humidified when the fuel cell is stopped so that it does not freeze even when the temperature drops to the ambient temperature.

[0007]

The above-mentioned conventional method has the following problems.

Problem of the method (1): When the fuel cell stack is heated by an electric heater, the temperature of a portion away from the electric heater is lowered by heat radiation to the outside. If the temperature of the electric heater is increased to avoid this, the fuel cell stack becomes too hot near the electric heater and the water in the phosphoric acid evaporates, and the concentration of phosphoric acid becomes higher than the concentration suitable for battery operation. Become. Usually, in order to avoid this, the electric heaters are dispersedly installed on a structure around the battery, for example, upper and lower clamping plates or a manifold.

In this case, the number of parts to be used increases and the cost increases. In addition, since the temperature is maintained by an electric heater, it is necessary to prepare a temporary power supply during a power outage or transportation due to an accident or construction. Also, since many of these electric heaters are mounted around the fuel cell stack, there are places where inspection and replacement are difficult. Therefore, when the electric heater fails, it is necessary to lower the fuel cell body from the power generator. or,
Since the generator is not required during operation, it is difficult to remove it despite its long non-use period, so it remains installed, resulting in poor cost performance.

Problems with the method (2): Even though the temperature of the fuel cell stack can be easily maintained to maintain the temperature with the cooling water, a larger power supply than that of the method (1) is required. Therefore, it is suitable for keeping heat for a short period after installation,
It is not suitable for keeping warm during long-term shutdown or transportation.

Problem of method (3): There is an advantage that an external power supply is not required during stoppage. However, in order to return phosphoric acid whose concentration has been reduced by humidification to a concentration suitable for operation, it is necessary to start the operation at the start of operation. It is necessary to heat the battery by the method (2) to evaporate the water in the phosphoric acid. Therefore, the operation cannot be started immediately. In addition, when the operation is stopped, a humidification step is required, so that the stop operation takes a long time. Therefore, this method is not suitable when it is required to shorten the work period before and after the stop of operation.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a phosphoric acid type fuel cell heat insulation apparatus which realizes the following.

(1) A simple and inexpensive device can be obtained by reducing the number of heating devices to be used.

(2) The heating device can be inspected while the fuel cell main body is mounted on the power generation device.

(3) The heating device for keeping heat can be easily detached, and it is not necessary to mount the heating device on the power generation device, and the structure can be shared by a plurality of power generation devices, thereby reducing the total cost.

(4) A heat retaining device that does not require a power supply or that can reduce the power supply capacity.

In short, an object of the present invention is to provide an inexpensive phosphoric acid-type fuel cell heat insulation device which can reduce the number of components and power supply capacity of a heating device for heat insulation and improve maintainability, thereby simplifying heat insulation and inexpensive. It is in.

[0018]

In order to solve the above-mentioned problems, in the present invention, a fuel cell main body is surrounded by a heat insulating member, and a gap through which air can convect between the main body and the heat insulating member is provided. The space is provided with a space heater for heating the air in the space (claim 1). Thereby, the number of heaters and the power supply capacity can be reduced.

In the above-mentioned apparatus, an inspection port for inspecting the space heater is provided near the space heater of the heat insulating member. This facilitates inspection and replacement of the space heater while being mounted on the power generator.

Further, as a configuration of a heat retaining device different from the above, a fuel cell main body, a heat insulating member surrounding the main body, a gap provided between the main body and the heat insulating member and through which gas can flow, A heating gas supply device such as air or combustion exhaust gas, wherein the heat insulating member includes a gas supply port and a discharge port for supplying and flowing the heating gas from the heating gas supply device to the gap. Claim 3). However, if the heat insulating member is non-hermetic and the heating gas supplied from the gas supply port can be discharged from the heat insulating member, only the gas supply port may be provided. ). Thereby, maintainability is further improved.

In the above-mentioned apparatus, there is provided a sealing member for sealing the gas supply port and the discharge port after heating the atmosphere in the gap and removing the heating gas supply device. By doing so, the heating gas supply device can be detached and used for keeping the temperature of other fuel cells. Of course, in the case of keeping the temperature for a long time, reheating is necessary as appropriate so that the temperature does not fall below the predetermined temperature.

Further, in the case of keeping heat for a short time, such as during transportation, the exhaust gas of the transportation vehicle may be supplied as a heating gas supply device. In this case, a special heating device becomes unnecessary. However, as described above, if the exhaust gas of automobiles or other combustion exhaust gas directly touches the fuel cell body, water vapor and unburned substances in the exhaust gas adhere to the cell body, causing rust and lowering the electrical insulation. Because of the danger, the fuel cell main body is provided with a covering sheet for preventing the fuel cell main body from directly contacting the flowing heating gas, and the fuel cell main body has a fuel cell operating temperature. Shall have heat resistance, electrical insulation, and waterproofness.

Further, it is desirable that the covering sheet is made of a polytetrafluoroethylene sheet or a glass-fiber-based silicone rubber-coated sheet.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment according to claims 1 and 2 of the present invention. A heat insulating member 5a is provided around the fuel cell main body 1 so as to provide a void 20 as an air layer through which air can flow. A space heater 6 is provided inside the heat insulating member 5a. When the battery is stopped, the space heater 6 is operated to raise the temperature of the air in the gap.

The air is convected by the temperature rise and the fuel cell body 1
In order to heat the fuel cell from all directions, the space heater 6 may be arranged at least at one place below in the heat insulating member 5a, and it is not necessary to arrange many heaters around the fuel cell main body 1.
Since there are few restrictions on the number of the space heaters 6 and the planar arrangement thereof, the space heaters 6 are installed at positions such as the door side of the power generation device package that can be accessed by an operator, and an inspection port is provided on the heat insulating member 5a at a position close to the space heaters. When the fuel cell body 7 is provided, the space heater 6 can be easily inspected and replaced without removing the fuel cell main body 1 from the power generating device.

FIG. 2 shows a second embodiment according to claims 3 to 6 of the present invention. A space 20 is provided around the fuel cell main body 1 so that air can convect similarly to FIG. further,
The heat-insulating member 5a has a supply port 1 for heated air or heated gas.
0 and an outlet 11 are provided. An electric heater, a heating gas supply device 13 that uses gas or oil combustion heat as a heat source is connected to a distal end of the supply port 10 on the outside of the heat insulation through a duct 12. The air heated by the heating gas supply device 13 is
The fuel cell body 1 is heated by flowing through the inside and exits through the outlet 11. The fuel cell body 1 is entirely covered with the heated air, and is uniformly heated from the surroundings.

FIG. 3 shows an arrangement example of the supply port 10 and the discharge port 11 in the embodiment of FIG. Heated air and fuel cell body
In order to make the contact 1 as long as possible, it is better to make the path in the gap 20 as long as possible. FIG. 3 (c),
In (d), the supply port 10 and the discharge port 11 are arranged so as to increase the plane distance and the height distance. 3 (a), 3 (b),
(D) and (e) show that the supplied heated air has a low specific gravity,
Paying attention to the fact that the air outlet becomes heavier as it is cooled, the discharge port 11 is provided at the lower part of the heat insulation to make it difficult for high-temperature air to escape from the gap 20. Further, in FIG. 2D, the supply port 10 is provided above the heat insulating member, and the arrangement is such that the heated air always passes around the fuel cell body 1.

FIGS. 3A to 3F show an example applied to a case where the air-tightness of the heat insulating member 5a is relatively good and it is difficult to supply heated air into the gap without an outlet. FIG. 3 (g)
Shows an example applied when the airtightness of the heat insulating member 5a is relatively poor. When the airtightness of the heat insulating member 5a is relatively poor, the heated air passes through the gap and is discharged from a plurality of locations of the heat insulating member without providing a discharge port.

In the embodiment shown in FIGS. 2 and 3, if the heated air is forcibly sent into the air gap by the exhaust pressure of the fan or the internal combustion engine, the flow of the heated air is accelerated, and the battery stack is operated even with a small heat source. Can be kept efficiently.

In the embodiment shown in FIGS. 2 and 3, if a lid (sealing member) for preventing the heat insulating effect from being lowered can be attached to the supply port 10 and the discharge port 11 of the heated air,
After the operation of the fuel cell is started, the heating gas supply device 13
Can be used to keep the fuel cell warm before starting another operation or during inspection, and the equipment can be used effectively.

Further, in addition to an electric heater, a heating engine such as a burner or an internal combustion engine or a combustion engine such as an oil is used as the heating gas supply device 13 to indirectly raise the temperature of the air and feed the air, or to exhaust the combustion exhaust gas. It is also possible to send in directly. However, when the combustion exhaust gas is sent directly to the periphery of the fuel cell body, there is a risk that water vapor, unburned matter, etc. in the combustion exhaust gas adhere to the fuel cell body 1 and cause problems such as deterioration of insulation properties and generation of rust. There is.

The covering sheet 9 shown in FIG. 2 is provided in order to avoid this danger, and the bag-on-sheet is made of a material having heat resistance, electrical insulation and waterproofness that can withstand the operating temperature of the fuel cell body 1. Then, the fuel cell body 1 is covered. Accordingly, water vapor, unburned matter, and the like contained in the combustion gas do not adhere to the fuel cell body 1. The covering sheet 9
FIG. 2 also covers the lower fastening plate 3b if necessary.
1 shows a configuration in which the covering sheet 9 is sealed at the end of the lower fastening plate 3b.

Examples of the material of the covering sheet 9 include:
There are a polytetrafluoroethylene sheet, a glass fiber-based silicone rubber sheet and the like.

Further, as the heating gas supply device 13, an automobile engine is also applicable. In particular, if exhaust gas from a transportation vehicle is used during transportation, there is no need to prepare temporary equipment. However, in the case of using the exhaust gas of the vehicle, all the exhaust gas from the muffler, which is the original exhaust gas line, is not introduced into the gap portion 20 but branched as necessary so as not to reduce the engine efficiency. Introduce some.

According to the present invention, a conventional heat retaining device can be used in combination. In particular, a conventional electric heater may be used in combination with a structurally large heat radiating portion, a lower fastening plate and the like.

[0037]

As described above, according to the present invention, the fuel cell main body is surrounded by the heat insulating member, and a gap through which air can flow is provided between the main body and the heat insulating member. The space heater for heating the air in the gap is provided (claim 1), and the inspection port for checking the space heater is provided near the space heater of the heat insulating member (claim 2). And the power supply capacity can be reduced, and the inspection and replacement of the space heater becomes easy.

Further, a heating gas supply device for supplying air or combustion exhaust gas is provided, and the heating gas is supplied from the gas supply port provided in the heat insulating member to the gap so that maintenance is possible. Is further improved,
In the above-mentioned apparatus, the heating gas is provided by heating the atmosphere in the gap, removing the heating gas supply device, and then sealing the gas supply port and the discharge port. The supply device can be removed and used for keeping the other fuel cells warm.

Furthermore, in the case of keeping the temperature for a short time, such as during transportation, the exhaust gas of the transportation vehicle is supplied as the heating gas supply device. can do. Also, to prevent the fuel cell body from directly touching the flowing heating gas,
By providing a covering sheet having heat resistance, electrical insulation and waterproofness (claims 5 and 6), water vapor and unburned substances in the exhaust gas adhere to the fuel cell body and generate rust. It is possible to prevent the danger of lowering the electrical insulation.

In general, as compared with the conventional fuel cell heat insulation apparatus, the number of parts and the power supply capacity of the heat insulation heating equipment can be reduced and the maintainability can be improved. A battery heat insulating device can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing an example of arrangement of supply ports and discharge ports in the embodiment of FIG. 2;

FIG. 4 is a schematic configuration diagram showing an example of a conventional heat retaining device for a fuel cell.

[Explanation of symbols]

1: fuel cell main body, 2: fuel cell stack, 3a: upper clamping plate, 3b: lower clamping plate, 4: manifold, 5a: heat insulating member, 6: space heater, 7: inspection port, 9: coating Sheet: 10: supply port, 11: discharge port, 13: heated gas supply device, 20: void.

Claims (8)

[Claims] 1. A fuel cell main body, a heat insulating member surrounding the main body, a gap provided between the main body and the heat insulating member, through which air can flow, and a gap provided in the gap, And a space heater for heating the air. 2. The heat insulation device for a phosphoric acid type fuel cell according to claim 1, wherein an inspection port for inspecting the space heater is provided near the space heater of the heat insulating member. 3. A fuel cell main body, a heat insulating member surrounding the main body, a gap provided between the main body and the heat insulating member, through which a gas can flow, and a heating gas supply device such as air or combustion exhaust gas. Wherein the heat insulating member has a gas supply port and a discharge port for supplying and flowing a heating gas from the heating gas supply device to the gap, and the phosphoric acid type fuel cell, Insulation device. 4. A fuel cell main body, a heat insulating member surrounding the main body, a gap provided between the main body and the heat insulating member and through which gas can flow, and a heating gas supply device such as air or combustion exhaust gas. The heat insulating member has a gas supply port for supplying and flowing a heating gas from the heating gas supply device to the gap, and the heat insulating member is non-hermetic and has a gas supply port. A heating device for a phosphoric acid type fuel cell, characterized in that the heating gas supplied from a mouth can be discharged from the heat insulating member. 5. The method according to claim 3, wherein after heating the atmosphere in the gap and removing the heating gas supply device,
A heat insulation device for a phosphoric acid type fuel cell, comprising a sealing member for sealing a gas supply port and a discharge port. 6. The fuel cell main body according to claim 3, wherein the fuel cell main body is provided with a covering sheet for preventing the fuel cell main body from directly contacting the flowing heating gas. , Heat resistance to fuel cell operating temperature,
A heat insulation device for a phosphoric acid fuel cell having electrical insulation and waterproofness. 7. The heat insulation apparatus for a phosphoric acid type fuel cell according to claim 6, wherein the covering sheet is made of a polytetrafluoroethylene sheet or a glass-fiber-based silicone rubber sheet. 8. The method according to claim 6, wherein
A heating device for a phosphoric acid type fuel cell, wherein the heating gas supply device is configured to supply exhaust gas from a transportation vehicle.