JPS63195971A - Stacked fuel cell - Google Patents

Abstract

PURPOSE:To prevent a drop in the outlet and a decrease in the life by installing a cooling unit which cools water vapor in a reaction gas into condensed water and an exhaust means which exhausts the condensed water while a reaction gas enters the latter half from the first half of a cell main body. CONSTITUTION:In an air return manifold 3, the water vapor in the air is cooled with a cooling pipe 11 in which water is circulated as shown in an arrow C and plate fins 14 installed around it. The cooled water vapor is condensed into water, and the condensed water drops and is gathered in a condensed water reservoir 16, then exhausted from a condensed water outlet 15 as shown in an arrow D. The flood of electrolyte caused by moisture absorption and expansion of electrolyte on the outlet side of the latter half 9 of a cell main body and the corrosion of an air electrode in a unit cell caused by the dilution of electrolyte can be prevented. Therefore, a drop in the outlet of a cell and a decrease in the life can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel cell, and particularly to a stacked fuel cell consisting of a plurality of unit cells electrically connected in series.

[Conventional technology]

In a stacked fuel cell, it is necessary to supply reactive gas to a plurality of i-cells without causing non-uniformity, and to improve the utilization rate of the reactive gas.

For this reason, a reaction gas supply method called "return flow" has been conventionally used. This is the special public service 58-228
This is a technique as described in Japanese Patent No. 66, and a typical conventional example thereof is shown in FIG. FIG. 4 is a cross-sectional view showing the stacked fuel cell, and FIG. 5 is a perspective view. In the figure, the main body of a stacked fuel cell (hereinafter referred to as a battery) is constructed by stacking a plurality of single cells, (2) is the inlet side and outlet side manifold for air, which is the reactive gas on the air side, and (3)
is an air return manifold, (4) is a manifold on the inlet side of the fuel gas which is the reaction gas on the fuel side, (5) is a manifold on the fuel outlet side, and (6) is a manifold on the fuel outlet side to prevent air from mixing on the forward flow side and reverse flow side. a barrier provided within the battery body (1);
(7) is the air inlet side piping, (8) is the air outlet side piping, (9) is the rear half of the battery body where air flows backward, and 0ω is the front half of the battery body where air flows forward. . In addition, the fifth
In the figure, the fuel side manifold (41151 is not shown for simplicity. In the figure, arrows indicate the flow of reaction gas, arrows (A) indicate the flow direction of air, and arrows (B) indicate the flow of fuel gas. Show direction.

Next, the operation will be explained. Fuel gas is supplied from the fuel inlet side manifold (4), and air is supplied from the air inlet side manifold (2). The battery body (1) is made up of stacked single cells each having an air electrode and a fuel electrode.
Chemical and electrochemical reactions take place while the reactant gases on the air side and the fuel side flow in a cross-flow manner. “Return Flow”
In this system, the battery body (1) is divided into a front half a0 of the battery body on the forward flow side and a rear half of the battery body (9) on the reverse flow side in terms of air flow. Regarding the air supplied as shown by the arrow Ell (A), after reacting in each unit cell of the front half αΦ of the battery body, it flows into the air return manifold (3). In this air return manifold (3), the air between the upper and lower parts is mixed and becomes uniform, and the rear half of the battery body (9)
) is supplied to each cell. In this way, in the stacked fuel cell using the "return flow" method, the reactant gases between the upper and lower sides are mixed once in the air return manifold (3), so the reactant gas is uneven in the rear half of the cell body (9). In addition, the stacked battery body (1)
This also has the effect of improving the in-plane temperature distribution of each unit cell.

Although FIGS. 4 and 5 show conventional examples in which return flow is applied to the air side, there are, of course, also conventional examples in which return flow is applied to the fuel side.

[Problem that the invention seeks to solve]

In a stacked fuel cell, a reaction gas is consumed and a product, water vapor, is generated and is mainly discharged to the air side where the flow rate is high. Therefore, the air return manifold (
3) contains a large amount of water vapor generated in the first half of the battery body (forward flow side) 0 [, and the second half of the battery body (reverse flow side) (9
). Therefore, on the outlet side of the battery main body rear half (9), the water vapor generated in the battery main body rear half (9) is further added, and a much larger amount of water vapor is supplied compared to the battery main body front half 00). Become. For this reason, the electrolyte absorbs moisture and expands on the outlet side of the rear half of the battery body (9), causing flooding, and the electrolyte is diluted, causing corrosion of the air electrode that makes up the cell. Problems such as acceleration may occur, resulting in a decrease in battery output,
There were problems such as shortened lifespan.

This invention was made to solve the above-mentioned problems, and it is a laminated layer that prevents flooding and dilution of the electrolyte on the outlet side of the rear half of the battery body, and prevents a decrease in battery output and shortened battery life. The purpose is to obtain a type fuel cell.

[Means for solving problems]

The stacked fuel cell according to the present invention is a stacked fuel cell in which +11 reaction gas is supplied from the inlet side manifold, circulated through the return manifold in the front half of the cell body, the rear half of the cell body in this order, and discharged from the outlet side manifold. Equipped with a cooler that cools the water in the reaction gas into condensed water while the reaction gas exits the front half of the battery body and enters the rear half of the battery body, and a discharge means to discharge the condensed water. It is.

[Effect]

The cooler in this invention cools water vapor in the reaction gas and removes condensed water from the battery body by the discharge means while the reaction gas exits the front half of the battery body and enters the rear half of the battery body. Reduces flooding and electrolyte dilution on the outlet side of the rear half of the main body.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a cross-sectional view showing a stacked fuel cell according to an embodiment of the present invention, and FIG. 2 is a perspective view as well. In the figure, aυ is a cooler, for example, a cooling pipe installed in the air return manifold (3), (2) is a cooling pipe inlet, 0
1 is the cooling pipe outlet, +41 is the plate fin provided around the cooling pipe, α is the condensed water outlet, and 05+ is the condensed water reservoir. The condensed water outlet α and the condensed water reservoir αQ constitute a condensed water discharge means. In the figure, arrow (A) is the flow direction of air, arrow (B) is the flow direction of fuel gas, and arrow (C
) indicates the flow direction of the refrigerant, such as water, flowing in the cooling pipe αυ, and arrow (D) indicates the flow direction of condensed water. The refrigerant flowing through the cooling pipe θυ may be a liquid or a gas. If it is a gas, the reaction gas is passed through the inlet side manifold f21. It may also be used as preheating by flowing it through the cooling pipe aυ before supplying it to +41.

Plate fin circles are a common means of increasing the surface area to enhance the cooling effect.

Note that the cooling pipe Oυ and the plate fin (b) must be corrosion resistant to the electrolyte.

As for operation, air and fuel gas react in the front half α of the battery body, as in the conventional case. Water vapor, which is a product, is generated here and is discharged mainly to the air side with a large flow rate, and flows into the air return manifold (3) together with the air. In the air return manifold (3), water vapor in the air is cooled by a cooling pipe αυ through which water circulates as shown by an arrow (C), and a plate fin αυ provided around the cooling pipe αυ. The cooled water vapor condenses into water, falls downward and is stored in the condensed water reservoir Q[9, and can be discharged from the condensed water outlet +151 as shown by arrow (D) if necessary. Like this air return manifold (
After some of the water vapor in the air is removed in the chamber 3), it is supplied to the rear half (9) of the battery body where chemical and electrochemical reactions occur. The amount of water vapor contained in the second half (9) of the battery main body is not much different from the amount of water vapor contained in the first half OI of the battery main body, and the battery reaction can be carried out efficiently. Therefore, on the outlet side of the rear half (9) of the battery body, the electrolyte absorbs moisture and expands, causing flounding, and also prevents corrosion of the air electrode that constitutes the cell due to dilution of the electrolyte. For this reason, you can
It is possible to prevent a decrease in battery output and shorten the lifespan of the battery.

FIG. 3 is a cross-sectional view showing another embodiment of the invention,
(2@ is a partition wall. In the embodiment shown in Fig. 3, there is a partition wall in the air return manifold (3).
21) is formed, and water vapor contained in the reaction gas is cooled and condensed inside the separate chamber (21). The condensed water generated by condensation is sent to the condensed water outlet a9 as in the above embodiment.
is discharged from. In yet another embodiment, a cooling pipe αυ may be disposed on the outer wall of the air return manifold +31 to cool it from the outside.

Furthermore, in addition to being cooled in the air return manifold (3) as in the above embodiment, the reaction gas containing water vapor is taken out once after exiting the front half αe of the battery body and cooled. The structure may be such that water vapor contained in the reaction gas is cooled and removed as condensed water while leaving the front half αe and entering the rear half (9) of the battery main body.

In addition, although the above embodiment shows the return flow on the air side, since water vapor is also discharged on the fuel side, a similar function may be provided to the return flow on the fuel side, and the same effect as in the above embodiment can be obtained. play.

〔Effect of the invention〕

As described above, according to the present invention, in a stacked fuel cell, a reactant gas is supplied from the inlet side manifold, circulated in this order through the first half of the cell body, the return manifold, and the second half of the cell body, and then discharged from the outlet side manifold. , a cooler that cools water vapor in the reaction gas to condensate water while the reaction gas exits the front half of the battery body and enters the rear half of the battery body;
By being equipped with a discharge means for discharging this condensed water, a stacked fuel cell can prevent flooding and dilution of the electrolyte on the outlet side of the rear half of the battery body, thereby preventing a decrease in battery output and shortening of battery life. There are benefits to be gained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a stacked fuel cell according to one embodiment of the present invention, FIG. 2 is a perspective view thereof, FIG. 3 is a cross-sectional view showing another embodiment of the present invention, and FIG. A cross-sectional view showing a conventional stacked fuel cell, and FIG. 5 is a perspective view as well. ill...stacked fuel cell main body, (2)...inlet side and outlet side manifolds, (3)...-return manifold, (9)...second half of the battery main body, aω...first half of the battery main body part, QO...Cooler, αS, OFA...Discharge means. In addition, in the figures, the same reference numerals do not indicate the same or equivalent parts. Agent Masuo Oiwa Figure 1 15:'f4W play Figure 3

Claims (3)

[Claims] (1) In a stacked fuel cell in which a reactive gas is supplied from an inlet manifold, circulated in this order through a return manifold in the front half of the cell body, a rear half of the battery body, and then discharged from an outlet manifold, the reactive gas is supplied from the first half of the cell body. A laminated type characterized by comprising a cooler that cools the water vapor in the reaction gas to form condensed water between the part and the rear part of the battery main body, and a discharge means to discharge the condensed water. Fuel cell. (2) The stacked fuel cell according to claim 1, wherein the cooler has a cooling pipe arranged inside the return manifold. (3) The stacked fuel cell according to claim 1, wherein the cooler has cooling pipes arranged on the outer wall of the return manifold.