JPS58135578A - Air-cooled fuel cell - Google Patents

Abstract

PURPOSE:To stabilize the cell performance and to improve the cell life by making a partial laminated body including a cooling plate one unit and by reversing the air flow direction to each other for individual adjoining units so as to keep the temperature distribution of the inlet side and the outlet side of a cell stack uniform. CONSTITUTION:The air fed by a blower 18 is branched into the first and the second introduction pipes 20, 21 through a feed pipe 19 and is fed to a stack 1 in the opposite direction to each other for individual units U through an introduction manifold 7. The air having passed through a reaction air feed groove 5 and an air passage 17 for each unit is collected to the first and the second efferent pipes 22, 23 through an efferent manifold 8, and a large part of the air collected by the efferent pipes 22, 23 is returned to a circulating pipe 24, but a part of the air is discharged outside through a discharge pipe 16 with a damper 14 and a cock 15. About 75% of the air fed to each unit U is fed to the cooling air passage 17 and the remaining about 25% is fed to the reaction air feed groove 5, and the temperature gradient rising from the inlet side toward the outlet side of each unit is heat-exchanged by the air stream flowing in the opposite direction to each other for the adjoining units.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air-cooled fuel cell, and an object of the present invention is to make the humidity distribution of a cell stack uniform.

The battery stack (1) consists of unit cells (2) as shown in Figure 1.
) and gas portion jllh13) alternately, several cells (
A cooling plate (4) is interposed every 4 to 5 inches.

In l1IiI#J of the gas separation plate (3), there are a reaction air supply groove (5) and a reaction hydrogen supply groove (6) so as to intersect with each other.
and air and hydrogen gas are respectively supplied through these grooves.

The battery reaction is carried out through the matrix material supplied to the back surface of each electrode and interposed between the opposite electrode plates.

As shown in Figure 2, a conventional air-cooled fuel cell has an air manifold (71 (8)) on the opposite side of the cell stack (1).
A hydrogen manifold 19>(10) is provided, and an air intake pipe opening having a cock (■) and a damper α4 and an exhaust pipe (α) having a cock are formed in the circulation path αυ connecting the air manifold (7081). In this case, the air sent to the introduction manifold (7) is divided into the reaction air supply groove (5) and the cooling air path αη of the cooling plate (4), and then merges at the outlet manifold (8).

During this time, the oxygen partial pressure of the reaction air decreases due to the cell reaction, and the cooling air absorbs the heat of the Shizuike reaction to maintain the operating temperature at around 180℃. Due to such a reaction, the circulation path Ql)
Approximately 10% of the amount of air flowing through the stack (1) is constantly renewed by supplying fresh air from the air intake WaJ and exhausting air from the exhaust pipe (to).

Therefore, the humidity on the stack inlet side is lower than that on the outlet side, and this can be seen in the humidity distribution on the electrode plate surface as shown in Figure 3 (as shown in tb+, the humidity difference between the inlet and outlet sides is over 40 degrees Celsius). , which caused deterioration of battery characteristics.

In the present invention, a unit cell between each cooling plate and one cooling plate are used as one unit, and each unit is provided with a pair of manifolds communicating with a reaction air supply groove and an air passage, so that the air supplied to each adjacent unit is mutually distributed. This allows the flow to flow in the opposite direction.

Embodiments of the present invention will be described below with reference to the drawings, and corresponding parts are designated by the same reference numerals as in the drawings.

FIG. 4 is an operating path diagram of the battery of the present invention, FIG. 5 is a detailed view of the main part, and FIG. 6 is a sectional view of the main part. First, in Fig. 6, a stack of a unit cell (2) consisting of an air electrode P, a hydrogen electrode (1) and an electrolyte matrix interposed therebetween and a gas separation plate (3) is a cooling plate (4). The cooling plate (4) is divided into a large number of partial stacks, and each manifold (75
These manifolds (7) and (8), on which ζ 85 are attached, are attached to opposite sides of the battery stack (1), and the adjacent manifolds on each side are used alternately for introduction and extraction.

The air sent to the manifold (7;
5) and the cooling air passage αη as shown by the arrows, but in the adjacent unit the air flows in the opposite direction via the corresponding manifold (71 (81).

In the supply route diagram in Fig. 4, the air sent by blower 4 is divided into the first and second introduction pipes (2) via supply pipe a9, and the introduction manifold (7) is connected to each unit U+. and are supplied to the stack (1) in opposite directions.

The air that has passed through the reaction air supply groove (5) and the air passage αh for each unit passes through the first outlet manifold (8). Most of the combined air from these outlet pipes returns to the reflux pipe, but some of it is discharged to the outside from the exhaust pipe GQ, which has a damper 04 and a cock. be done. Intake pipe 0 with cock D at the same time
The fresh air introduced from the above and the recirculated air are mixed in the supply pipe 09 and are supplied to the stack (1) as described in 1. The amount of air sent to each Unilido U+ is approximately 75% through the cooling air passage. αη, and the remaining approximately 251 are reaction air supply grooves (5
), but the humidity gradient that rises from the inlet side to the outlet of each UniSoto is exchanged by the airflow flowing in opposite directions between adjacent units, and the humidity gradient increases between the stack inlet side and the outlet side. Approximately equalizes the humidity difference between the sides.

As described above, the battery stack according to the present invention has 1 unit and 12 partial stacks including cooling plates (a stack of unit cells and gas separation plates between the cooling plates), and the air flow direction is reversed for each adjacent unit. Since heat exchange is performed between the air flow that separates the cooling air passage of each unit and the reaction air groove, the difference in humidity between the inlet and outlet sides of the battery stack, which was conventional, is eliminated and the temperature distribution is uniform. ``It is expected that the battery life will be improved rather than the stability of the battery performance.In addition, in this method, a pair of manifolds are required for each 22-meter battery, but a thick cooling plate is required. Since these manifolds can be installed using the above-mentioned method, there is no need to take much time in terms of construction and it is highly practical.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a battery stack, FIG. 2 is an operating path diagram of a conventional battery, and FIG. 3 (a) is a temperature distribution diagram on the electrode plate surface of a conventional battery. FIG. 4 is an operating path diagram of the battery of the present invention, FIG. 5 is a detailed view of the main parts showing the state of air circulation within the manifold and stack, and FIG. 6 is an enlarged sectional view of the main parts. (1)...Battery stack, (2)...Unit cell,
f3)...Gas separation plate, (4)...Cooling plate, (5)
...Reaction air supply groove, (6)...Reaction hydrogen gas supply groove, α-ri...Cooling air passage, Ut...Units),
(7) (a+...Introduction and extraction manifold, 0...
Air intake pipe, QIS...Exhaust pipe, G! J... Supply pipe, ■ @... 1st, 2nd introduction pipe, ■... 1st,
Second outlet pipe, □□□...Recirculation pipe. 11 13 Arate/l distance flI

Claims (1)

[Claims] (1) A battery stack in which unit cells and gas separation plates are stacked alternately and a cooling plate is interposed between every few cells is divided into a plurality of units each including the several cells and one cooling plate, and each unit・Providing a manifold for each unit that communicates with the reaction air supply groove of the gas separation plate and the air passage of the cooling plate, and making the supply air of each adjacent unit flow in opposite directions through the manifold, which is patented. Air-cooled fuel cell.