JPH07118330B2 - Gas header for fuel cell and fuel cell using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas header for a fuel cell and a fuel cell using the same, and in a fuel cell of an internal manifold type as the cell area increases, the reaction gas is uniformly distributed in each manifold. The present invention relates to a suitable gas header structure that can be supplied at various temperatures.

[0002]

2. Description of the Related Art A structure shown in FIG. 5 has been proposed as a cell and stack laminated structure effective for increasing the area of a cell. As the cell, a composite large capacity cell having a plurality of unit cells 22 on one plane is considered. Further, the reaction gas in each unit cell 22 of this cell is supplied and exhausted by the manifold n in the unit cell provided at the outer peripheral portion and the central portion of the cell. Further, the gas in the manifold is a plurality of gas headers having an inlet gas chamber, an outlet gas chamber, and a pipe connected to each of the gas chambers, that is, in this figure, a fuel gas that is a reaction gas on the anode side. Are supplied and discharged by an anode gas header 23 located above and below the stack and a cathode gas header 1 ′ located at the center of the stack for an oxidizing gas, which is a reaction gas on the cathode side.

As the capacity of the fuel cell increases in the future, it is expected that the gas header will be further increased in size. As a measure against this, a gas header structure for supplying gas into a unit cell as shown in FIG. In a gas bed 1 ″ of a fuel cell having a gas chamber for supplying and exhausting gas, a connecting chamber 53 is provided between the gas chambers 51 and 52 on both outer sides in the gas header to integrate the gas chamber. A U-shape is formed on a plane, and a gas chamber 54 is formed by utilizing the central space of the U-shape. Further, the respective gas chambers are separated from each other by a partition plate 55 at a position adjacent to each other. A gas header structure in which a header internal structure is formed has been proposed (see Japanese Patent Application No. 2-241108, which belongs to the same applicant as the present invention), wherein 56 and 57 are supply and exhaust manifolds. , 58 The gas header has a unique structure that simplifies the structure of the gas header itself and facilitates battery handling. Therefore, there is an effect that the total height of the laminated stack can be reduced.

[0004]

In the fuel cell, it is important that the temperature of the gas supplied to each cell be uniform, from the viewpoint of improving power generation efficiency. In the cell, since the distance from the gas supply pipe to the gas supply manifold is generally short, the deviation of the temperature of the gas flowing into each manifold is
It didn't matter. However, the conventional technology corresponding to the large cell area to obtain a high output, in particular, the gas header structure on the cathode side has a gas supply pipe on the side surface of the inlet gas chamber and the oxidant gas is supplied from the gas supply pipe. The gas is supplied directly into the inlet gas chamber, and the distance between the manifold near and the manifold far from the gas supply piping is long. Therefore, the gas flowing into the inlet gas chamber is gradually heated by the heat of the battery main body from the side of the gas supply pipe, and the deviation of the gas temperature between the manifold near the gas supply pipe and the manifold far from the gas supply pipe becomes large. Furthermore, in each unit cell, it is affected by the above,
There is a problem that the temperature distribution in the cell plane becomes non-uniform and the performance and the life are shortened.

The present invention is for a fuel cell which can supply a reaction gas having a uniform temperature from the gas header to each gas supply manifold, thereby making the temperature distribution in each unit cell and cell plane uniform. An object is to provide a gas header structure and a fuel cell using such a gas header.

[0006]

In order to achieve the above-mentioned object, the present invention provides a gas header having a side portion for connection with an inlet gas supply pipe and a plurality of inlet gas manifolds inside thereof. A gas for a fuel cell, characterized in that the gas supply opening to the gas header is located in the center of the inside of the gas header, and the gas supply opening and the connection portion with the inlet gas supply pipe are connected via a gas flow path. A header and a fuel cell using the gas header are disclosed.

By making the gas flow path in contact with a higher temperature portion in the gas header and allowing heat exchange with the inlet gas, the temperature distribution in each unit cell and cell surface can be made uniform. The intended purpose can be achieved more reliably.
Furthermore, the heat exchange capacity is further improved by bringing at least a part of the gas flow path into contact with the outlet gas flow path in the gas header.

Further, by providing the gas flow passages in two lines in a symmetrical manner with respect to the center line of the gas header, it becomes possible to appropriately cope with a larger stack structure. The header structure of the present invention can be used on either the cathode side or the anode side, but is particularly effective when applied to the cathode side gas header.

[0009]

When the gas header structure of the present invention is applied to the inside of the cathode gas header, the oxidant gas flows from the gas supply pipe into the heat exchange passage adjacent to the outlet gas passage, and the cathode gas is discharged. It flows into the gas supply port provided in the center of the header. The oxidant gas in the heat exchange channel is
Due to the heat of reaction in the cell, heat is exchanged by the heat of the outlet gas having a high temperature. The oxidant gas from the gas supply port is
Further, heat is exchanged to a temperature required for battery operation while passing through the heat exchange flow path, and is supplied into each unit cell through each gas supply manifold.

By adopting the gas inflow structure in the cathode gas header of the present invention, the oxidant gas from the gas supply pipe can be supplied into each gas supply manifold at a uniform temperature. It is possible to supply a gas having a uniform temperature even in each unit cell while reducing the deviation of the gas temperature of the above.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a partially cutaway perspective view of the cathode gas header when the present invention is applied to the cathode gas header, and FIG. 2 is a cross section of the heat exchange flow path portion of the present invention taken along line II-II of FIG. It is a figure. As shown in FIG. 1, the cathode gas header 1 of this embodiment has a space surrounded by upper and lower substrates 2 and 2'and a frame plate 3 provided on the outer peripheral portions of the four sides of the substrate. Further, among the frame plates 3 of the gas header 1, the gas supply pipes 17 are provided on one side and the gas supply pipes 17 on the other side at substantially central portions in the width direction of the frame plates 3a and 3b (left and right frame plates in FIG. 1) facing each other. The gas exhaust pipe 18 is joined. And gas supply pipe 1
At a position symmetrical with respect to a line PP connecting the center of 7 and the center of the gas exhaust pipe 18, two partition plates 4 ′, 4 ′ having one end in contact with the frame plate 3 a and the other end extending in the frame plate 3 b direction. "" Is provided, and the extending end sides of the two partition plates 4'and 4 '"are frame plates 3b.
It is joined by another partition plate 4 ″ with a predetermined space between and.

Therefore, the gas header 1 is divided into two spaces by the frame plate 3 and the partition plate 4, and each space is mutually sealed so that gas does not leak. In the following, the space surrounded by the partition plate 4 is defined as the inlet gas chamber A,
The space surrounded by the frame plate 3 and the partition plate 4 is called an outlet gas chamber B. Further, the two partition plates 4 ', 4''' are joined by the second partition plate 12 at a position close to the frame plate 3a connecting the gas supply pipe 17, and the gas supply path 11 is connected thereto. The second partition plate 12 has openings 13, 13 'near the joints with the partition plates 4', 4 '''. As is clear from the above description, the gas header 1 has a symmetrical shape with respect to the center line PP. In the following, only one of the configurations will be described and the other description will be omitted.

The inlet gas chamber A has an inlet gas flow passage 7 which is surrounded by a partition plate 4 ″, a second partition plate 12 and a heat exchange flow passage, which will be described later, substantially at the center, The gas chamber B has outlet gas passages 8 on both sides and a connecting passage 5 for connecting both passages. In addition, reinforcing ribs 6a (inlet gas chamber A side) and 6b (outlet gas chamber B side) having a plurality of holes are provided in each gas chamber to reinforce the space. .

The inlet gas chamber A of the gas header 1 in the present invention is further separated from the partition plate 4'to the second partition plate 1 at a position separated from the partition plate 4'by a predetermined distance in the direction of the center line PP.
It has the 3rd partition plate 21 to 2 and, and is a partition plate 4 '.
And a third partition plate 21 are formed with a heat exchange flow path 9, and the third partition plate 21 has an opening at a substantially central position in the length direction, and a gas supply opening is provided there. Forming 10.

Therefore, the cathode gas from the gas supply pipe 17 passes through the gas supply channel 11 formed by the frame plate 3a and the second partition plate 12, and the opening 13 formed in the second partition plate 12. After passing through the partition plate 4 ′ and the third partition plate 21, the heat exchange passage 9 is passed between the partition plate 4 ′ and the third partition plate 21 and the third partition plate 2
1 through the opening 10 to reach the inlet gas flow path 7.
Further, a plurality of gas supply manifolds 15 for supplying gas into each unit cell are provided on the upper and lower substrates 2 and 2 ′ at a position corresponding to the above-mentioned inlet gas flow passage 7, and at the outlet gas flow passage 8. A plurality of exhaust gas manifolds 16 for sucking gas exhaust gas from each unit cell are provided at corresponding positions.

FIG. 2 shows a sectional view of a preferred embodiment of the structure of the heat exchange channel 9. In this example, the heat insulating layer forming plates 19 are provided above and below the heat exchange channel 9 to form the substrate 2,
A heat insulating layer 20 is provided to form a space between the 2'and the heat insulating layer forming plate 19 and to make it difficult for heat in the cell to be conducted into the gas header. In addition, a partition reinforcing plate 22 having an opening for reinforcing the inside is provided in the heat exchange channel 9.

Next, the gas flow in the structure of the gas header 1 will be described with reference to FIGS. 1 and 2. The oxidant gas x before the reaction, which is the gas on the cathode side, first flows into the gas supply flow passage 11 from the gas supply pipe 17 provided in the central side part (frame plate 3a) of the gas header. Supply channel 11
It is distributed to both sides inside and flows into each heat exchange passage 9 through the gas inlet 13 of the second partition plate 12. The oxidant gas x before the reaction that has flowed into the heat exchange channel 9 is branched from the gas supply port 10 at the center of the gas header through the hole of the reinforcing rib 6a on the inlet side into each gas supply manifold 15. Gas flows downward on the gas header and is supplied into each unit cell (not shown). And in each unit cell,
The reacted oxidant gas x ′ that has been exhausted through the reaction passes through the gas exhaust manifold 16 outside both of the gas headers and is dispersed in the outlet gas chamber outside both of the gas headers. The dispersed gas is used as a reinforcing rib 6b on the outlet side in the outlet gas chamber.
Through the hole and the outlet gas flow path 8 and collected into the connection flow path 5, and the connection flow path 5 is also connected to the outside by a gas exhaust pipe 18 provided in the central side part (frame plate 3b) of the gas header. Is discharged to.

Therefore, in the cathode gas header 1, the heat exchange passage 9 of the inlet gas chamber and the outlet gas passage 8 are located adjacent to each other, and the gas supply port is provided at the center of the cathode gas header 1. Since 10 is provided, the oxidant gas x having a low temperature before the reaction has been heated in the heat exchange channel 9 by the reaction heat in the unit cell after the reaction. Heat is exchanged through the partition plate 4, and the heat-exchanged oxidant gas x before reaction is further supplied from the gas supply port 10 at the center of the cathode gas header 1 into each gas supply manifold 15. Further, as a result, the temperature of the oxidant gas x rises, and at the same time, it becomes possible to make the flow paths between them, that is, the distances of the gas flow paths from the gas supply pipe 17 to each gas supply manifold 15 substantially equal.

As a result, the temperature distribution in each unit cell and the cell plane can be made uniform, and the power generation efficiency of the fuel cell can be improved. 3 and 4 show another embodiment of the gas header according to the present invention. Both of these
The gas flow path between the gas supply flow path 11 and the gas supply opening 10, that is, the length of the heat exchange flow path 9 is made more uniform by interposing a plurality of baffle plates 30 so as to be more uniform. The oxidant gas x before the temperature reaction can be supplied into each gas supply manifold 15 through the central gas supply opening 10. In these two examples, by changing the shape of the gas flow path, that is, by further increasing the length of the gas flow path up to the heat exchange flow path 9 and the gas supply manifold 15, in the flow path, In addition to the heat of the outlet gas, not only the heat of the battery body but also the heat of the oxidant gas x before the reaction is exchanged to a more uniform temperature and a temperature required for battery operation, and is supplied into each gas supply manifold 15. I have to. A heat insulating layer (not shown) may be provided in the heat exchanging flow path portion as needed, as in the structure of FIG.

In the above embodiment, the gas flow path between the inlet gas supply pipe 17 and the gas supply port 10 has been described as having a structure capable of positively performing the function of heat exchange. The purpose of is to positively heat the gas flow path between the inlet gas supply pipe and the gas supply port if the gas supply opening to the inlet gas manifold is configured to be located in the center of the inside of the gas header. It will be clear that this can be achieved without having a mechanism for carrying out the exchange, for example a configuration in which the gas flow path is placed in contact with the outlet gas flow path.

Further, the upper and lower substrates 2 of the gas header 1,
2'has been described as consisting of a single plate,
From the viewpoint of convenience in assembling, maintaining, or managing the gas header, one or both substrates are divided into a plurality of divided members, for example, a portion corresponding to the inlet gas chamber A and a portion corresponding to the outlet gas chamber B. You can also choose to do so. Furthermore, although the cathode gas header has been described in the above embodiments, the present invention is equally applicable when used in the inlet gas chamber of the anode gas header for supplying the fuel gas into each gas supply manifold. , A similar effect can be obtained.

[0022]

According to the present invention, the flow path length from the gas supply pipe to each gas supply manifold is substantially the same, and the oxidant gas is provided in the flow path between them at a temperature necessary for battery operation. Since the heat can be exchanged up to the temperature, the temperature of the oxidant gas flowing into each gas supply manifold becomes uniform, and there is an effect that the deviation of the gas temperature between the gas supply manifolds is reduced. Further, there is an effect that a uniform temperature distribution can be achieved in each unit cell. Thereby,
The power generation efficiency of the fuel cell can be improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a cathode gas header according to the present invention.

FIG. 2 is a cross-sectional view of the heat exchange flow path section taken along line II-II in FIG.

FIG. 3 is a view showing another embodiment of the cathode gas header according to the present invention.

FIG. 4 is a view showing still another embodiment of the cathode gas header according to the present invention.

FIG. 5 is a diagram showing a stacked state of a stack.

FIG. 6 is a partially cutaway perspective view of a conventional cathode gas header.

[Explanation of symbols]

1 Cathode Gas Header 2 Substrate 3 Frame Plate 4 Partition Plate 5 Connection Channel 6a Inlet Side Reinforcing Plate 6b Outlet Side Reinforcing Plate 7 Inlet Gas Channel 8 Outlet Gas Channel 9 Heat Exchange Channel 10 Gas Supply Port 11 Gas Supply flow path 12 Second partition plate 13 Gas inlets 14a, 14b Lid plate 15 Gas supply manifold 16 Gas exhaust manifold 17 Gas supply pipe 18 Gas exhaust pipe 19 Heat insulation layer forming plate 20 Heat insulation layer 21 Third partition plate x Reaction Previous oxidant gas x'Oxidant gas after reaction

Front page continuation (72) Inventor Tsutomu Takahashi 3-1-1, Saiwaicho, Hitachi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor Tadashi Yoshida 3-1-1, Saiwaicho, Hitachi, Ibaraki Stock company Hitachi Ltd.Hitachi factory

Claims (4)

[Claims] 1. A gas header for a fuel cell, which is arranged in a stack of an internal manifold type fuel cell having a plurality of unit cells on one plane and supplies and discharges gas to and from each unit cell, in which gas is supplied to opposite sides. A pipe and a gas exhaust pipe are connected, a plurality of gas supply manifolds for supplying the supply gas from the gas supply pipe to each unit cell are arranged in the central portion, and the gas from each unit cell is sandwiched on both outer sides of the central portion. A plurality of gas exhaust manifolds for sucking exhaust gas and exhausting to the gas exhaust pipes are arranged, and the gas supply pipes, the gas supply manifolds, the gas exhaust manifolds, and the gas exhaust pipes are formed of partition plates. Gas supplied from the gas supply pipe flows through a flow path in contact with a flow path through which the gas exhaust flows, and then the plurality of gases A gas header for a fuel cell, which is supplied to a supply manifold. 2. The flow path of the supply gas and the flow path of the gas exhaust are with respect to a line connecting the center of the side portion to which the gas supply pipe is connected and the center of the side portion to which the gas exhaust pipe is connected. 2. It is provided symmetrically with respect to each other.
Gas header for fuel cell described. 3. An internal manifold fuel cell comprising a stack in which a plurality of unit cells having a plurality of unit cells are stacked on one plane, and a gas header which is stacked on the stack and supplies and discharges gas to and from each unit cell, The gas header has gas supply pipes and gas exhaust pipes connected to opposite sides thereof, and a plurality of gas supply manifolds for supplying the supply gas from the gas supply pipes to the respective unit cells are arranged in the central portion of the gas header. A plurality of gas exhaust manifolds for sucking gas exhaust from each unit cell and exhausting the gas exhaust pipes to the gas exhaust pipes are disposed on both outer sides of the portion, and the gas supply pipes, the gas supply manifolds, and the gas exhausts are arranged. The manifold and the gas exhaust pipe are connected by a flow path formed by a partition plate, and the gas supplied from the gas supply pipe is the gas exhaust pipe. An internal manifold fuel cell, which is supplied to the plurality of gas supply manifolds after flowing through a flow path in contact with a flow path. 4. The flow path of the supply gas and the flow path of the gas exhaust are lines connecting a center of a side portion to which the gas supply pipe is connected and a center of a side portion to which the gas exhaust pipe is connected. The internal manifold fuel cell according to claim 3, wherein the internal manifold fuel cell is provided symmetrically with respect to the internal manifold fuel cell.