JPH1154140A - Fuel cell power generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide power generating characteristics at a low cost by heating and supplying oxidant gas by a simple constitution, and achieving a uniform inplane temperature distribution. SOLUTION: A pipeline 15 is disposed in contact with the wall surface of an oxidant gas supply manifold 2 attached at the side surface of a fuel cell layered body 1. One end of the pipeline 15 is connected to a cell cooling water supply pipe 10 for supplying cell cooling water to the fuel cell layered body 1 through a cooling pipe 13, and the other end is connected to a cell cooling water discharging pipe 11 for converging the cell cooling water discharged through a cooling pipe 14, so that oxidant gas is heat-exchanged with the cell cooling water, and then, is supplied to the fuel cell layered body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphoric acid type fuel cell power generation apparatus which incorporates a manifold into a side surface of a fuel cell stack and supplies a reaction gas to generate power, and more particularly to an oxidizing gas supply structure. About.

[0002]

2. Description of the Related Art FIG. 6 is a plan view showing an example of the configuration of a fuel cell stack having gas supply and discharge manifolds on the side surfaces. The fuel cell stack 1 is formed in a square shape by stacking a large number of flat unit cells in which a matrix holding phosphoric acid is sandwiched between a fuel electrode and an oxidant electrode, and oxidant gas is provided on opposing side surfaces. A supply manifold 2 and an oxidant gas discharge manifold 3 are arranged, and a fuel gas supply manifold 4 and a fuel gas discharge manifold 5 are arranged on the other opposite side perpendicular to these, so that the oxidant gas and the fuel gas intersect at right angles. The method of letting it flow is adopted. That is, the atmosphere is usually used as the oxidizing gas, and the oxidizing gas is sent from the oxidizing gas supply pipe 6 to the oxidizing gas supply manifold 2 at the atmospheric temperature to separate the oxidizing electrodes of many cells of the fuel cell stack 1. And flow into the oxidant gas discharge manifold 3
The oxidant gas is discharged to the outside through the discharge pipe 7. On the other hand, a reformed gas having a high hydrogen concentration is used as the fuel gas, and is supplied at a temperature close to the operating temperature of the fuel cell stack of about 190 ° C. The fuel gas sent from the fuel gas supply pipe 8 to the fuel gas supply manifold 4 flows back and forth between the fuel gas discharge manifold 5 and the fuel gas discharge pipe 9 in order to increase the efficiency. Is discharged.

[0003] The power generation reaction in a unit cell is an exothermic reaction, and it is necessary to eliminate the heat generation in order to maintain the unit cell at a predetermined temperature. For this reason, the fuel cell stack 1 is laminated by appropriately inserting a cooling plate, and the battery cooling water sent to the battery cooling water supply pipe 10 shown in the figure passes through the cooling pipes embedded in each cooling plate. The fuel cell stack 1 is caused to flow from the discharge side of the oxidant gas to the supply side, and is discharged from the cell cooling water discharge pipe 11 to remove heat.
Is maintained at about 190 ° C.

[0004]

As described above, in a phosphoric acid type fuel cell, the temperature of the fuel cell stack is about 190 ° C.
, And the fuel gas is also supplied at substantially the same temperature, but the air as the oxidizing gas is supplied at a normal atmospheric temperature. For this reason, as shown in FIG. 8, looking at the in-plane temperature distribution of the unit cells stacked in the fuel cell stack, the temperature on the oxidant gas supply side tends to decrease. As the temperature decreases, the power generation characteristics also decrease, so that not only the characteristics of the battery as a whole deteriorate, but also an excessive reaction occurs in a high-temperature portion to compensate for the decrease in the characteristics. This will cause deterioration of the characteristics.

In order to solve this difficulty, the temperature of the oxidizing gas may be increased and supplied. For example, a heat exchanger 12 is provided as shown in FIG. A method is employed in which the oxidizing gas is heated by exchanging heat with the oxidizing gas to be discharged, and the oxidizing gas is heated to a high temperature. FIG. 9 is a characteristic diagram showing the in-plane temperature distribution of the fuel cell stack in this method. There is no decrease in the temperature on the oxidant gas supply side, and the power generation characteristics are higher than those in FIG. .

However, in such a method in which the heat exchanger 12 is provided, the oxidizing gas which is heated and discharged by the power generation reaction contains the vapor of phosphoric acid used for the electrolyte of the unit cell. Since there is a risk of phosphoric acid condensing inside the heat exchanger 12 due to heat exchange with the supply oxidizing gas having a low temperature and causing corrosion to proceed and being damaged, a configuration for preventing this is provided. However, there is a disadvantage that the cost is high because the necessity and the installation space are required.

SUMMARY OF THE INVENTION An object of the present invention is to provide a simple configuration in which the temperature of an oxidizing gas to be supplied is effectively increased, and the cost is low without causing corrosion of equipment, an increase in installation space, or an increase in cost. An object of the present invention is to provide a fuel cell power generation device having excellent power generation characteristics.

[0008]

In order to achieve the above object, in the present invention, a fuel cell stack is constituted by stacking a plurality of unit cells with a cooling plate interposed therebetween as appropriate,
The cell cooling water supplied to the cell cooling water supply pipe arranged close to the fuel cell stack flows through the cooling plate to maintain the fuel cell stack at a predetermined temperature, and the manifold incorporated into the side surface of the fuel cell stack is provided. In a fuel cell power generator operated by flowing an oxidizing gas and a fuel gas through a fuel cell stack using the fuel cell, (1) a battery in which the oxidizing gas supplied to the fuel cell stack is supplied to a cell cooling water supply pipe A heat exchange means for exchanging heat with the cooling water is provided. (2) For example, a pipe branched from the battery cooling water supply pipe and diverted from the battery cooling water, or the battery cooling water after flowing through the cooling plate is used. The flowing pipe is arranged in close contact with the wall surface of the manifold for supplying the oxidizing gas.

(3) Alternatively, a pipe branched from the battery cooling water supply pipe is connected to a cooling water tank disposed inside the manifold for supplying the oxidizing gas, and the battery cooling water is divided.
(4) Alternatively, the pipe for diverting the battery cooling water branched from the battery cooling water supply pipe, or the pipe for flowing the battery cooling water after flowing through the cooling plate is closely attached to the oxidizing gas supply pipe. And distribute them.

The battery cooling water serves to remove the heat generated by the power generation reaction and to maintain the fuel cell stack at an operating temperature of about 190 ° C. Therefore, the battery cooling water supplied to the battery cooling water supply pipe is , Is kept at a high temperature. Therefore, as described in (1) above, if the oxidizing gas supplied to the fuel cell stack is subjected to heat exchange with the cell cooling water, the oxidizing gas is effectively heated, and the oxidizing gas having an increased temperature is heated. Is supplied to the fuel cell stack, so that a temperature drop on the inlet side of the oxidizing gas as in the conventional case is avoided, and the power generation characteristics are improved.

In particular, in the case of (2) or (3), the oxidizing gas effectively exchanges heat with the cell cooling water inside the oxidizing gas supply manifold, and after the temperature rises, the fuel cell If the oxidizing gas is supplied to the laminate and the temperature is raised by effectively exchanging heat with the battery cooling water in the oxidizing gas supply pipe according to (4), the oxidizing gas is supplied. Is supplied to the fuel cell stack, so that a decrease in temperature at the inlet side of the oxidizing gas is avoided, and the power generation characteristics are improved.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

<Embodiment 1> FIG. 1 shows a first embodiment of a fuel cell power generator according to the present invention.
It is a principal part perspective view which shows the heat exchange means of the Example of FIG. In addition,
In the figure, only the oxidizing gas supply manifold 2 among the four manifolds incorporated in the fuel cell stack 1 is shown, and the others are omitted.

The feature of this configuration is that the cooling pipe is branched from the battery cooling water supply pipe 10 provided with a cooling pipe 13 communicating with a cooling plate (not shown) incorporated in the fuel cell stack 1 and communicates with the cooling plate. A pipe 15 connected to the battery cooling water discharge pipe 11 provided with the pipe 14 is provided in close contact with the wall surface of the oxidizing gas supply manifold 2. In this configuration, the fuel cell stack 1 is heated and supplied to maintain the fuel cell stack 1 at a predetermined operating temperature of about 190 ° C.
5 will be diverted. The oxidizing gas is heated by exchanging heat with the cell cooling water flowing through the pipe 15 in the oxidizing gas supply manifold 2, heated, and then supplied to the fuel cell stack 1. Therefore, the in-plane temperature distribution of the fuel cell stack 1 is made more uniform without lowering the temperature on the inlet side of the oxidizing gas as in the prior art, and good cell characteristics are obtained.

<Embodiment 2> FIG. 2 is a perspective view showing a main part of a heat exchange means of a fuel cell power generator according to a second embodiment of the present invention. This configuration is characterized by a large number of cooling pipes 14A which communicate with a cooling plate (not shown) incorporated in the fuel cell stack 1 and through which the discharged battery cooling water flows, and discharge these battery cooling waters by combining them. The battery cooling water discharge pipe 11 is disposed in close contact with the wall surface of the oxidizing gas supply manifold 2.

Also in this structure, the oxidizing gas is heated by exchanging heat with the cooling water flowing through the cooling pipe 14A and the battery cooling water discharge pipe 11 in the oxidizing gas supply manifold 2, and is heated. As a result, the temperature distribution in the plane of the fuel cell stack 1 is made uniform without lowering the temperature on the inlet side of the oxidizing gas, and good cell characteristics can be obtained. Becomes

<Embodiment 3> FIG. 3 is a perspective view showing a main part of a heat exchange means of a fuel cell power generator according to a third embodiment of the present invention. The feature of this configuration is that the oxidant gas supply manifold 2
A cooling water tank 16 is provided on the wall surface of A, a pipe 17 is provided between the cooling water tank 16 and the battery cooling water supply pipe 10, and a pipe 18 is provided between the cooling water tank 16 and the battery cooling water discharge pipe 11. It is in the point.

In this configuration, the oxidizing gas is heated by exchanging heat with the battery cooling water diverted to the cooling water tank 16 in the oxidizing gas supply manifold 2A, heated, and then heated to the fuel cell stack 1. As a result, the temperature distribution in the plane of the fuel cell stack 1 is made uniform,
Good battery characteristics will be obtained. <Embodiment 4> FIG. 4 shows a fourth embodiment of the fuel cell power generator according to the present invention.
It is a principal part perspective view which shows the heat exchange means of the Example of FIG. This configuration is characterized in that the oxidizing gas supply pipe connected to the oxidizing gas supply manifold 2 is partially connected to the battery cooling water discharge pipe 11.
In that it is provided with a double tube 19 formed so as to cover a part of the double tube.

In this configuration, the oxidizing gas is heated by exchanging heat with the battery cooling water in the double pipe 19 and is heated, and then supplied from the oxidizing gas supply manifold 2 to the fuel cell stack 1. Therefore, the in-plane temperature distribution of the fuel cell stack 1 is made uniform, and good cell characteristics are obtained. <Embodiment 5> FIG. 5 shows a fifth embodiment of the fuel cell power generator of the present invention.
It is a principal part perspective view which shows the heat exchange means of the Example of FIG. The feature of this configuration is that a pipe 20 for connecting the battery cooling water supply pipe 10 and the battery cooling water discharge pipe 11 is wound around a part of the oxidizing gas supply pipe connected to the oxidizing gas supply manifold 2. It is located at the point.

Also in this configuration, the oxidizing gas is heated by exchanging heat with the battery cooling water flowing through the pipe 20 in the oxidizing gas supply pipe, and after the temperature rises, the fuel cell is supplied from the oxidizing gas supply manifold 2 to the fuel cell. Since the fuel is supplied to the stack 1, the in-plane temperature distribution of the fuel cell stack 1 is made uniform, and good cell characteristics are obtained.

[0020]

As described above, according to the present invention, a fuel cell stack is formed by stacking a plurality of unit cells with a cooling plate interposed therebetween as appropriate, and arranged in close proximity to the fuel cell stack. The battery cooling water supplied to the battery cooling water supply pipe flows through the cooling plate to maintain the fuel cell stack at a predetermined temperature, and the oxidant gas is supplied to the fuel cell stack using the manifold incorporated on the side of the fuel cell stack. And a fuel cell power generation device that operates by flowing fuel gas, wherein a heat exchange means is provided for exchanging heat between the oxidizing gas supplied to the fuel cell stack and the battery cooling water supplied to the battery cooling water supply pipe. For example,
(1) The pipe for diverting the battery cooling water branched from the battery cooling water supply pipe or the pipe for flowing the battery cooling water after flowing through the cooling plate is closely attached to the wall surface of the oxidant gas supply manifold. And distribute them. Or,
(2) A pipe branched from the battery cooling water supply pipe is connected to a cooling water tank disposed inside a manifold for supplying an oxidizing gas, and the battery cooling water is divided. Alternatively, (3) the pipe for diverting the battery cooling water branched from the battery cooling water supply pipe or the pipe for flowing the battery cooling water after flowing through the cooling plate is closely attached to the oxidizing gas supply pipe. Since the oxidizing gas is heated by exchanging heat with the cell cooling water and is heated and then supplied to the fuel cell stack, the temperature in the plane of the fuel cell stack is increased. A fuel cell power generator with uniform distribution, low cost, and excellent power generation characteristics has been obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part showing a heat exchange unit of a first embodiment of a fuel cell power generator according to the present invention.

FIG. 2 is a perspective view of a main part showing a heat exchange unit of a second embodiment of the fuel cell power generator according to the present invention.

FIG. 3 is a perspective view of a main part showing heat exchange means of a third embodiment of the fuel cell power generator according to the present invention.

FIG. 4 is a perspective view of a main part showing a heat exchange unit of a fourth embodiment of the fuel cell power generator according to the present invention.

FIG. 5 is a perspective view of a main part showing a heat exchange unit of a fifth embodiment of the fuel cell power generator according to the present invention.

FIG. 6 is a plan view showing a configuration example of a fuel cell stack having gas supply / discharge manifolds arranged on side surfaces;

FIG. 7 is an explanatory diagram of a gas supply system for supplying an oxidizing gas heated by using an oxidizing gas to be discharged to a fuel cell stack;

FIG. 8 is a characteristic diagram showing an in-plane temperature distribution of a fuel cell stack in a conventional gas supply system.

9 is a characteristic diagram showing an in-plane temperature distribution of the fuel cell stack in the gas supply system of FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel cell laminated body 2 Oxidant gas supply manifold 2A Oxidant gas supply manifold 10 Battery cooling water supply pipe 11 Battery cooling water discharge pipe 13 Cooling pipe 14 Cooling pipe 14A Cooling pipe 15 Pipe 16 Cooling water tank 17 Pipe 18 Pipe 18 Duplex Pipe 20 Piping

Claims (4)

[Claims] A fuel cell stack is formed by stacking a plurality of unit cells with a cooling plate interposed therebetween as appropriate, and the battery cooling unit is supplied to a battery cooling water supply pipe disposed close to the fuel cell stack. The fuel is operated by flowing water to the cooling plate to maintain the fuel cell stack at a predetermined temperature, and flowing the oxidizing gas and the fuel gas through the fuel cell stack using a manifold incorporated on the side of the fuel cell stack. A fuel cell power generator, comprising: a heat exchange means for exchanging heat with oxidant gas supplied to a fuel cell stack with battery water supplied to a cell cooling water supply pipe. 2. The fuel cell power generator according to claim 1, wherein the heat exchanging means includes a pipe for diverting battery cooling water from the battery cooling water supply pipe or a cooling plate. A fuel cell power generator, wherein a pipe through which the cell cooling water flows is closely attached to a wall surface of a manifold for supplying an oxidizing gas. 3. The fuel cell power generator according to claim 1, wherein the heat exchange means connects a pipe branched from the battery cooling water supply pipe to a cooling water tank arranged inside a manifold for supplying oxidant gas. And a fuel cell power generation device, wherein the fuel cell power generation device is connected to the fuel cell and shunts the battery cooling water. 4. The fuel cell power generator according to claim 1, wherein the heat exchange means includes a pipe for diverting the battery cooling water branched from the battery cooling water supply pipe, or the heat exchange means flowing through the cooling plate. A fuel cell power generator, wherein a pipe through which the battery cooling water flows is closely attached to a pipe for supplying an oxidizing gas.