JPS61128472A - Fuel cell - Google Patents

Abstract

PURPOSE:To prevent performance decrease caused by increase in cell size by arranging preheaters within fuel and air manifolds mounted outside the fuel cell main body and passing high temperature fluid generated in a system into the preheater. CONSTITUTION:A fuel cell is assembled in such a way that preheaters 12 into which high temperature fluid 13 generated in a system is passed are arranged in fuel and air manifolds 3, 5 mounted outside a fuel cell main body 1 and accommodated inside the pressure container covered with heat insulating material 11 through a thermal shield 7. Temperature of fuel and air is increased with the preheaters 12 and they are supplied for electrochemical reaction. Even when the size of a plate of fuel cell is increased, temperature decrease in a unit cell is prevented and e.m.f. of the cell can be maintained same as that of the small cell. Therefore, efficient power generation is obtained.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a fuel cell, and by installing a preheater inside the fuel and air manifold attached to the outside of the stacked cell, it is possible to improve the efficiency of the fuel cell as it becomes larger. The present invention relates to a fuel cell that can prevent performance deterioration caused by such a drop in average temperature.

[Background of the invention]

Conventionally, heat exchangers were generally not installed in the fuel and air manifolds, and heat radiation was mainly prevented by using insulation material outside the pressure spring that covered the stacked fuel cell. According to this, as the plate size of the fuel cell increases, the average temperature of the reunit cell decreases due to the temperature drop around the plate, and the electromotive force E of the battery decreases according to the following equation, resulting in a decrease in performance. It has been considered difficult to increase the size of the battery because of this problem.

E=f (T) [Object of the Invention] The object of the present invention is to install a preheater in the fuel and air manifold to be supplied to the battery main body, and to supply the fuel by flowing a heated fluid with a high temperature level in the power generation system. Alternatively, the average temperature of each unit cell can be increased by preheating the air and preventing a temperature drop at the edge of the plate due to an increase in battery size, thereby preventing a drop in electromotive force. The object of the present invention is to provide a highly efficient fuel cell that can improve the performance of each stack.

[Summary of the invention]

In order to achieve large-capacity power generation in a fuel cell power generation system, it is necessary to increase the size of the fuel cell plate. However, as the size of the fuel cell increases, the temperature distribution within the separator becomes larger compared to one with a smaller size.

The average temperature of the plate drops. As a result, the electromotive force E is proportional to this average temperature, so the electromotive force decreases and the performance inevitably deteriorates. By installing a heating fluid at a high temperature level within the system, the average temperature within the manifold is increased and the fuel cell plate is heated.

[Embodiments of the invention]

An embodiment of the present invention will be explained with reference to FIG. First, in the structure of the present invention, the fuel cell body 1 stacked inside a cylindrical pressure vessel 9 is installed on a vertical vessel support stand 1o. Around the battery body 1, there are provided a fuel manifold and an air manifold necessary for uniformly flowing the fuel 2 and air necessary for the electrochemical reaction inside the battery into the fuel passage and the air passage. It is installed.

However, in FIG. 1, the air manifold is omitted. Therefore, the following explanation will focus on the flow of fuel, but the content can be similarly considered even if replaced with the flow of air. At this time, a fuel supply pipe 4 is attached to the fuel supply manifold 3, and a fuel exhaust pipe 6 is attached to the fuel exhaust manifold 5. Here, 7 stations for fuel supply are installed. As this heat source, a heating fluid 131 with a high temperature level in the system, for example, high-temperature gas in a reformer, etc. is used.

Furthermore, since the temperature inside the battery body 1 and each manifold 3, 5 is high, a heat shield 7 is installed between the pressure vessel 9 and the manifold to prevent heat radiation, especially radiation heat loss. of course,
The outside of the pressure vessel 1 is covered with a heat insulating material 11.

Next, the operation of the present invention will be explained. The fuel 2 coming out of the discharger passes through a fuel supply pipe 4 and enters a fuel supply manifold 3, where it is heated by a preheater 12 and distributed in a uniform flow rate to fuel passages within the battery body 1. Air also enters the battery body 1 in a similar flow, where electrochemical reaction generates an electromotive force E, and the fuel 2 collects in the fuel exhaust manifold 5 and flows out from the fuel exhaust pipe 6. The same goes for air. At this time, as shown in Fig. 2, in the case of a generally small battery size A, for example, a battery of 300 x 300 m/m, considering the small unit cell 1a, even if temperature distribution occurs within the separator, the size is small. , shows a relatively high value under the average temperature. However, when the battery size is large, for example 1000 x 1000 m /
In the case of a battery of m, even considering the large unit cell 1b,
Same maximum temperature T as the small size, 1. Even if the same temperature distribution is produced, the average temperature at that time 〒〒-0' will be considerably lower.

Therefore, when a large battery size and a preheater inside the manifold are added as in the present invention, it is possible to prevent the temperature drop at the end face of the battery body, and under the average temperature at that time,
becomes 〒,>T,', and it is possible to avoid a decrease in average temperature due to an increase in battery size. Then, the finally required electromotive force E exhibits electrical characteristics as shown in FIG. 3 due to the relationship of decrease in E.

As the battery size increases, if a preheater 12 is installed in each manifold, a heat shield 12 can be installed between the electromotive force unit and the lead to reduce heat radiation loss due to radiation to the outside. It is prevented.

〔Effect of the invention〕

As is clear from the above invention, according to the present invention, when the battery size is increased, by installing a preheater in the fuel and air manifolds, a drop in the average temperature within the unit cell can be prevented. An electromotive force similar to that obtained when the electromotive force is small can be obtained, and a large-capacity fuel cell power generation system can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between fuel cell size and cell temperature distribution. FIG. 3 is a diagram showing the relationship between fuel cell size and electromotive force. DESCRIPTION OF SYMBOLS 1... Battery body, 2... Fuel, 4... Fuel supply pipe, 5... Fuel exhaust manifold, 6... Fuel exhaust pipe, 7... Figure 1/l Certain 2c21 ( CL) 71t3 Mouth as revenge J

Claims (1)

[Claims] 1. A fuel cell characterized in that a preheater is installed inside the fuel supply and exhaust manifolds installed outside the stacked fuel cell main body and inside the air supply and exhaust manifolds.