JPS61260551A - Air cooling type fuel cell - Google Patents

Abstract

PURPOSE:To acquire a simple structure, a compact size, and a compact auxiliary driver of a fuel cell, by installing cylindrical heat pipes with heat exchanging fins, at the end of a box type heat pipe group, and combining them to the box type hat pipes. CONSTITUTION:At the end surface of box type heat pipes 2, are installed plural cylindrical heat pipes 3 projecting from the unit cell members, and both heat pipes 2 and 3 are combined within the system. At the outer periphery of a heat pipe 3 are furnished heat exchanging fins 4. At the ceiling of the stack case 16 is furnished a fan 7, which blows in hot air or cool air to a ventilation duct 6a of the stack case 6, blows air to the cylindrical pipes and the heat exchanging fins to heat or cool them, and exhausts the sir through the bottom of the stack case 6.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention is a fuel! The present invention relates to an air-cooled fuel cell in which unit cells are stacked, each consisting of an oxidizer electrode and an oxidizer electrode, and particularly relates to a heating-cooling structure of a fuel cell stack in which the unit cells are stacked.

[Prior art and its problems]

Fuel cells (a device that directly converts the chemical energy of fuel into electric energy IC!) are a new type of fuel cell because they have the advantages of high thermal efficiency, low noise, and low emissions9). He is attracting attention as Lie. However, there is a problem with this fuel cell that its characteristics deteriorate as the operating temperature decreases. Therefore, the unit cell of the fuel cell must be raised to a predetermined temperature.

Generally, when a fuel cell is used as an 'IIt@, rapid power generation is required. Therefore, it is necessary to make it possible to obtain the rated output as quickly as possible after turning on the switch.

Normally, electrolyte, fuel, and other chemicals are supplied to the unit cell, a load is connected, and power generation below the rated value is continued until the temperature of the unit cell rises to a predetermined value due to heat generated by the internal resistance of the unit cell. There are two methods: waiting for the unit cell to reach its rated output, or supplying an externally heated electrolyte to raise the temperature of the unit cell, but both methods have the problem that it takes a long time to reach the rated output. be.

To address this problem, a method was developed in which the surface of the unit cell is heated from the outside to promote the temperature rise to a predetermined value, thereby quickly achieving the rated output.

One example of this method is an air-cooled fuel cell.

The structure of this type of air-cooled fuel cell will be explained based on the perspective views shown in FIG. 5g6 and FIG. First, the fuel cell stack 1 shown in FIG. 6 is mounted with a cooling plate 1b sandwiched between the unit cells 1a, and a plurality of cooling air #ICs are drilled in the cooling plate 1b to circulate cooling air. Sauce, unit cell 1a
A plurality of reaction air grooves 1d are provided on the surface thereof, and a plurality of fuel (hydrogen) supply grooves 1e are provided on the fourth surface in a direction perpendicular to the reaction air grooves 1d. In the case of FIG. 7, the reaction air groove 1d and the fuel supply groove 1e are provided in the same direction, and the cooling air groove is bored in a direction perpendicular thereto.

In order to increase power generation efficiency in any structure, a large amount of air is allowed to flow through this cooling air groove IC to minimize the temperature difference between the cooling air inlet side and the outlet side, and the average temperature of the cooling air is In the case of phosphorous fuel cells, the temperature is over 100 degrees,
A method has been adopted in which the temperature within the unit cell surface is made uniform. There are two methods for this: a method in which a portion of the high-temperature exhaust gas is returned, mixed with ambient temperature outside air, and then circulated and supplied using a blower; and a method in which the exhaust gas is cooled to a predetermined temperature through a heat exchanger and then circulated. This configuration is shown in FIG. In the figure, fuel (hydrogen) is supplied to the fuel cell stack 1 in the direction shown by the Taihi arrow, but the air that heats (or cools) the fuel cell stack 1 flows inside the circulation duct 2, shown by the m-line arrow. flow in the direction. This circulation duct 2 has a heating heater 3. Blower 4. Heat exchanger5. D/B 6 etc. are installed.

It is well known that the pressure loss in the flow path increases as the temperature of the fluid being handled increases, and the power of the blower increases in proportion to the amount of air blown and the pressure loss in the flow path. Flowing means increasing the size.Furthermore, in order to blow the high-temperature fluid, the blower was also required to be heat resistant, so a heat-resistant type IL machine had to be used. Also heat '2Hm#1MJ
Heater for heat.

Because it is equipped with automatic valves, ducts, etc., it has the disadvantage of being structurally complex and large in size, making it unsuitable for applications with strict size restrictions such as mounting on vehicles. .

[Purpose of the invention]

In view of the above-mentioned circumstances, the purpose of this invention is to provide an air-cooled fuel cell that is simple to use, has a small size, and requires only a small amount of auxiliary power.

[Key points of the invention]

In this invention, a plurality of cylindrical heat pipes are made to protrude from at least one end surface of a box-shaped heat pipe that is formed into a rectangular shape to match the shape of a unit cell, and each of the cylindrical heat pipes is connected to the box-shaped heat pipe. In addition to attaching several heat exchange fins to the outside, the front box-shaped heat pipe is sandwiched between fuel cell stacks consisting of unit cells, and this is housed in a container to blow hot or cold air from one side of the container. was fed into the container, ventilated through the cylindrical heat pipe and the heat exchange heat pipe, heated or cooled, and then exhausted from the other side of the container. In other words, by connecting and attaching a cylindrical heat pipe with heat exchange fins to the end of a box-shaped heat pipe, it is possible to increase the temperature difference between the inlet and outlet of hot or cold air.
The heat-uniforming effect of the heat pipe reduces the temperature difference within the unit cell plane and between the unit cells in the stacking direction, increasing the power generation efficiency and reducing the blower power because the amount of air flow is small and the ventilation resistance is small. It is something that we try to do.

[Embodiments of the invention]

FIG. 1 is a side cross-sectional view of an embodiment of the present invention, in which a fuel cell star and a fuel cell star are sandwiched between box-shaped heat pipes 2 which are rectangularly shaped to match the shape of the unit cell. 11 and housed in a stack case 6 via a heat insulating material 5.

A plurality of cylindrical heat pipes 13 are provided on the end surface of the box-shaped heat pipe 2, protruding from the unit cell part. A plurality of heat exchange fins 4 are attached. A blower 7 is provided on the ceiling of the stack case 6, and the blower 7 sends hot or cold air into the ventilation duct 111 of the stack case 6 to pass through the cylindrical heat pipe and heat exchange fins for heating or cooling. It has a ventilation structure that cools and exhausts air from the bottom of the star 6. This ventilation structure is opposite to the direction shown in the diagram.
That is, a configuration may also be used in which the air supply K (i7f) is provided on the bottom surface of the stack case 6, and the ventilation direction in the ventilation duct 1-6a is from the bottom to the top, and the air is exhausted from the ceiling surface of the stack case 6.

When hot air is to be ventilated, it is sufficient to provide a heating heater (not shown) on the intake side of the blower A machine 7, and to pass the intake air from the blower IL machine 7 through this heater, and hot air can be obtained with extremely simple equipment. When blowing cold air, the heater is inactive (does not heat) and the blower 7 is operated to blow cold outside air. i-style.

The structure of the box-shaped heat pipe 2 described above will be explained based on a plan sectional view shown in FIG. 3 and FIG. 4 showing a cross section taken along the line A--A in FIG. 3. The box-shaped heat pipe 2 is a rectangular one surrounded by a heat equalizing plate 2a, and is in contact with a unit cell of the fuel cell stack 1, and the opposing heat equalizing plate 2a is supported by a modified version 2b via a wick material 2C. It will be done. This corrugated sheet 2b is not a single piece, but is cut in the middle as shown in the wca diagram (the place where the wick material 2C at the bottom is visible in Figure 3). This is to ensure that the upper air and lower air in the space divided by the corrugated plate 2b are exchanged. In other words, the cylindrical heat pipe 3 protruding from the end surface of the box-shaped heat pipe 2 communicates with the inside of the box-shaped heat pipe 2, and the heated air or cooled air inside the cylindrical tote vibe 3 is connected to the interior of the box-shaped heat pipe 2. The air flows into either the upper space or the lower space divided by the corrugated plate 2b inside the box-shaped heat pipe 2, and the air is replaced in the space where the corrugated plate 2b is not provided. The aim is to equalize the temperature by heating or air cooling.

FIG. 2 is a plan sectional view showing another embodiment of the present invention, in which parts having the same configuration as those in FIG.
1 omitted. 12 in the figure is a reaction gas supply manifold, 1
3 is a sealing material, and the difference from FIG. 1 is that the blower 7 is attached to either the left or right side of the stack case 6, so in FIG. There is a temperature difference between cells in the stacking direction that corresponds to the temperature difference between the inlet and the outlet, but in the case of Figure 2, the temperature of the hot air or cold air in the PkJv71 direction is uniform, and even if there is a temperature difference between the population and the outlet, there is no heat difference. Due to the heat-uniforming effect of the pipe, there is almost no temperature difference within the plane of the unit cell, and the temperature difference can be maintained at about 1'C at most.

〔Effect of the invention〕

According to the present invention, a fuel cell stack K consisting of a uniform number of unit cells and a box-shaped heat pipe each having a plurality of cylindrical heat pipes each having peripheral pressure heat exchange fins at the ends are combined and housed in a stack case. However, the structure is such that a blower installed on one side of the stack case blows hot or cold air to the cylindrical heat pipe and heat exchange fins, and the air is exhausted from the other side of the stack case, so the entire air-cooled fuel cell device The structure is simple, and the dimensions are small and it is possible to put together a small size. Furthermore, since there is no problem even if the temperature difference between the inlet and the outlet of the 21 wind or cold air is made large, the amount of ventilation can be reduced and the ventilation resistance can be made extremely small. As a result, the transport Jt mobility can be reduced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an air-cooled fuel cell according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an air-cooled fuel cell according to another embodiment of the present invention. A cross-sectional plan view of the pond, Figure 3 is similar to Figures 1 and 2.
A cross-sectional plan view of a box-shaped heat pipe used in the air-cooled fuel cell shown in the figure, FIG. 4 is a cross-sectional view taken along the line A-A in FIG. 3, and FIG. 5 is a 9-cooled fuel cage with a conventional structure. In the system diagram, cause a is ff? of the air-cooled fuel cell stack with the conventional structure. +View,
FIG. 7 is a perspective view of another air-cooled fuel cell stack having a conventional structure. 1: fuel cell stack, 2: box-shaped heat pipe, 3: cylindrical heat pipe, 4: heat exchange fin, 6: container (stack case). ↓ Figure 1 111 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1) A plurality of cylindrical heat pipes are made to protrude from at least one end surface of a box-shaped heat pipe formed in a rectangular shape to match the shape of a unit cell, and communicate with each of the box-shaped heat pipes, A plurality of heat exchange fins are attached to the outer periphery of the cylindrical heat pipe, and the box-shaped heat pipe is sandwiched between a fuel cell stack consisting of stacked unit cells, and this is housed in a container. An air-cooled fuel cell characterized in that hot air or cold air is sent in from one side, passed through the cylindrical heat pipe and heat exchange fins located in the ventilation duct of the container, and then exhausted from the other side of the container. 2) In the product described in claim 1, the box-shaped heat pipe is a rectangular one surrounded by a heat-uniforming plate, and the two opposing sides that contact the unit cells of the fuel cell stack are connected via a wick. An air-cooled fuel cell characterized by a structure supported by corrugated plates.