JPS6129077A - Cooling device for fuel cell - Google Patents

Abstract

PURPOSE:To uniformize temperature at both upper and lower sides, by feeding cooling air to be fed to a cooling plate of a cell stack with pressure from the underside of an inlet side manifold whose thickness is reduced in proportion as it goes upward from the lower part. CONSTITUTION:A unit cell and a gas separator plate are alternately stacked up and at every stacked cell, a cooling plate is interposed in between, thus a fuel cell stack 1 is formed. A cooling gas manifold 21 at the inlet side and a manifold 21' at the outlet side, made up into such a form as being reduced the thickness in proportion as it goes upward from the lower part, are attached to the side, while a pressure-feed duct 23 of a blower 22 is connected to an interconnecting port at the underside of the manifold 21 at the inlet side, and further straightening plates 24 and distributing plates 25 are installed in the inside, distributing air quantities, and cooling air is fed to four substacks of the stack 1. Accordingly, air velocity distribution to each cooling plate over both upper and lower parts is uniformized, equalizing temperature, thus a cell characteristic is improvable.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field This invention relates to a gas-cooled fuel cell, and particularly to a cooling device in which a cooling gas is pumped from below an inlet side manifold in the stacking direction of the cell stack. It is.

(b) Conventional technology Since the temperature of a fuel cell increases due to the heat of reaction, cooling is required to maintain the operating temperature at around 180°C.

There are two methods for supplying the cooling gas: one method is to supply the cooling gas toward the battery stack stacking surface, and the other is to supply the cooling gas along the battery stack stacking surface. However, in the former case, as the inlet duct protrudes laterally and the height of the stack increases, the thickness of the inlet manifold increases, which is disadvantageous in terms of space, especially when a cooling gas path is shared for a plurality of stacks. -The latter has the advantage that the inlet duct can be formed on the bottom surface of the manifold and the thickness of the manifold can be reduced, but as the stack height increases, it becomes difficult to distribute the cooling gas evenly, and the temperature varies between the top and bottom of the battery stack. There were many problems that caused this to occur and deteriorate the battery characteristics.

CI Problems to be Solved by the Invention The present invention aims to make the stack temperature uniform by uniformly distributing cooling gas supplied along the stacking surface of the battery stack to the cooling passages above and below the stack.

B) Means for Solving the Problems This invention is characterized in that the inlet side manifold, which is dammed on the peripheral surface where the cooling passage of the battery stack opens, has a shape whose thickness decreases from the bottom to the top, and a cooling gas is provided on the bottom surface of the inlet manifold. The pressure-feeding ducts are connected, the inside of the duct is divided by a plurality of rectifying plates so that the air volume in each divided passage is uniform, and the inside of the manifold is divided by a distribution plate connected to each of the rectifying plates, so that the stack This is a book in which the cooling gas is divided into each substack, which is divided into equal parts.

(E) Effect According to this invention, the cooling air pumped by the blower is
Since the current is evenly distributed to each sub-stack by the current plate and the distribution plate and introduced into the cooling passage, even if the stack height is large, the temperature can be made uniform across the top and bottom of the stack.

(f) Example Embodiments of the invention will be described with reference to the drawings.

The battery stack ill consists of degree cell (2) and gas separation plate (
3) are stacked alternately in large numbers, and a cooling plate (4
), and is tightened between the upper and lower end plates i7) by a tightening member consisting of a suppressing piece (5) and a connecting rod (6). A cooling passage (8) of a cooling plate is opened on one opposing circumferential surface of the battery stack (1), and an inlet/outlet (9) for a hydrogen gas passage and an inlet/outlet (10) for a reaction air passage are opened on the other opposing circumferential surface. )
is open.

A frame-shaped sealing material (ll) is placed on each circumferential surface of the battery stack (ft).
The rigid frame f+20al is brought into contact with the rigid frame f+20al, and between the adjacent rigid frames, the retaining piece H welded to one side and the pole H19 implanted in the other are engaged, and each pole) (fli
The battery stack (1) is tightened from the outer periphery by screwing together a nut 0η through a spring 0 and elastically connecting these four frames H (+1) to each other.

In addition, one rigid frame 0 has a partition (not shown) that divides each flow surface of hydrogen gas and reaction air, and this partition has a sensitive seal integrated with the frame-shaped sealing material (ll). It is in pressure contact with the stack surface through the section. A rigid frame (1η) having this partition body is connected to a composite manifold O (1η) consisting of hydrogen gas and reaction air manifolds via a second sealing material QIIG.
) is tightened and fixed with screws.

Similar to the composite manifold 4, the cooling gas manifold '' (211 (21) is also connected to the rigid frame α (
(support) is tightened and fixed with screws. The cooling gas manifold (21) on the inlet side has a shape in which the thickness decreases as it moves downward and upward, and a blower (two pressure-feeding ducts) are installed at the communication port on the bottom surface of the manifold (21), as shown in Figure 3. The part of this duct away from the blower discharge port is constructed so that the air volume in each passage divided by the rectification factor is equal.

On the other hand, inside the inlet side manifold) 'I' 21) is a distribution plate (divided by 2 uniforms, which distributes cooling air to each of the four sub-stacks that evenly divides the stack m) connected to each of the rectified root cuttings 4). The flow is divided into each cooling passage (8).

The high-temperature cooling air that flows through each cooling passage (8) and exits from the stack m is returned to the blower (22) via the outlet manifold (21+) and the exhaust duct (a), but in the meantime, the high-temperature cooling gas is It is cooled by a heat exchanger (not shown).

The outlet side manifold (21) and the exhaust duct Ha) do not require the gas distribution plate (24) and the rectifying plate a5) as described above.

Figure 3 shows the case of 300 cell stack, and the distribution plate (2
Each substack includes unit cells (2) of 75 and 14 cooling plates (4) divided into four parts.

Figure 4 is a characteristic diagram showing the wind speed distribution in the cooling passages (8) of the upper and lower totals 56 for this 300-cell stack. ) was measured and each wind speed was calculated from the cross-sectional area of the passage. Similarly, the results of measuring the wind speed distribution using the longitudinal type inlet side manifold shown in FIG. 5 are shown in the characteristic diagram of FIG.

As is clear from the comparison of these characteristic diagrams, it can be seen that the device of the present invention significantly improves the air velocity distribution in the cooling passages extending above and below the stack.

In the above embodiment, the case has been described in which each manifold is attached to the rigid frame body 011 that tightens the battery stack +1) from the outer periphery, but the manifolds may be attached directly to the battery stack [1] as usual. In this case, the tip of each distribution plate that divides the inside of the input manifold (1) will face the stack surface with an insulating gap when it is installed through a rigid frame. It is similar to

(G) Effects According to the present invention, the cooling gas pumped by the blower is distributed in the duct by a rectifying plate that divides the inside of the duct to equalize the air volume in each divided passage, and then to the inlet side manifold whose thickness decreases from the bottom to the top. The inside of this manifold is divided by a distribution plate connected to the rectifying plate, and the cooling gas is divided into each sub-stack to evenly divide the stack. As a result, the air velocity distribution in each cooling passage is significantly improved, which becomes particularly advantageous as the stack height increases. Therefore, it is possible to make the stack temperature uniform both above and below, thereby improving battery characteristics.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a battery equipped with the device of the present invention, Fig. 2 is an exploded perspective view of the same essential parts as above, Fig. 3 is a vertical cross-sectional view of a 300-cell stack in which the device of the present invention is adopted, and Fig. 5 4 and 6 are longitudinal cross-sectional views of the case in which the device of the present invention is equipped with force.
The figures are characteristic diagrams showing a comparison of the wind speed distribution in the cooling passages extending above and below the stack for the product of the present invention shown in FIG. 3 and the conventional product shown in FIG. 5, respectively. 1: Battery stack, 2: Unit cell, 3: Gas separation plate, 4
: Cooling plate, 8; Cooling passage, 12113 : Rigid frame, 2
1, 21: Cooling gas inlet and outlet side manifold,
22 Nib blower, 23: Pressure feeding duct, 24: Current plate, 25
: Distribution board.

Claims (1)

[Claims] A battery stack in which a large number of unit cells and gas separation plates are alternately stacked and a cooling plate having a cooling passage is interposed for every several unit cells, the battery stack being mounted on the circumferential surface of the stack where the cooling passage opens. The cooling gas manifold on the inlet side has a shape that contracts from the bottom to the top, and a cooling gas pressure feeding duct is connected to the bottom surface of the cooling gas manifold. A cooling device for a fuel cell, characterized in that the manifold is divided by a plate and the inside of the manifold is divided by a distribution plate connected to the rectifying plate, so that cooling gas is divided into each sub-stack evenly divided into the stack. .