JP3063204B2 - Molten carbonate fuel cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten carbonate fuel cell.

[0002]

2. Description of the Related Art In recent years, research and development of a molten carbonate fuel cell have been conducted.

The structure of an example of a molten carbonate fuel cell will be described below with reference to FIGS.

[0004] 1 is a substantially horizontal rectangular electrolyte plate obtained by impregnating a porous substance with a carbonate such as LiCO ₃ or K ₂ CO ₃ or pressing the carbonate together with a holding material. Is a flat plate-shaped anode whose planar shape is smaller than the electrolyte plate 1 and is in close contact with the upper surface of the electrolyte plate 1; On the upper surface of the substrate, a large number of holes 4 having a plane shape substantially the same as the anode 2 and penetrating in the plate thickness direction are provided.
A punch plate 5 having the same shape as that of the punch plate 5 contacts the lower surface of the cathode 3.

Reference numeral 7 denotes a rectangular frame-shaped mask plate surrounding the anode 2 and the punch plate 5 in the circumferential direction, and 8 denotes a rectangular frame plate-shaped mask plate surrounding the cathode 3 and the punch plate 6 in the circumferential direction. The lower surface 7 is in close contact with the peripheral edge of the upper surface of the electrolyte plate 1, and the upper surface of the mask plate 8 is in close contact with the peripheral edge of the lower surface of the electrolyte plate 1.

Reference numeral 9 denotes a separator having a corrugated portion having a slightly larger planar shape than the punch plate 5. The bottom portion 10 of the corrugated portion of the separator 9 has an upper surface of a non-perforated portion of the punch plate 5 and a mask. A plurality of fuel gas flow paths 11 which are in close contact with the upper surface of the plate 7 and extend substantially horizontally from one end A to the other B between the lower surface of the corrugated portion of the separator 9 and the punch plate 5. Is formed.

On the other hand, on the upper surface of the separator 9, the above-mentioned punch plate 6, the cathode 3 and the mask plate 8 are laminated. A plurality of oxidizing gas flow paths which are in close contact with the lower surface of the mask plate 8 and extend substantially horizontally from one end A side to the other end B side between the upper surface of the corrugated portion of the separator 9 and the punch plate 6. 13 are formed.

A seal 14 formed on the outer edge of the separator 9 is in close contact with the outer edge of the upper surface of the mask plate 7 and the outer edge of the lower surface of the mask plate 8.

As described above, in the fuel cells shown in FIGS. 5 to 8, the electrolyte plate 1 between the separators 9, the anode 2,
Cell 1 which is a constituent unit of the fuel cell by cathode 3 and the like
5 are formed to form a stack 16 in which a plurality of the cells 15 are stacked.

At one end A of each cell 15, a fuel gas inlet penetrating through the separator 9, the mask plate 7, the electrolyte plate 1, and the mask plate 8 substantially vertically, and communicating with one end of the fuel gas passage 11. The flow path 17 and the oxidizing gas flow path 1
An oxidizing gas inlet flow path 18 communicating with one end of each cell 3 is formed, and a separator 9,
The fuel gas passage 11 penetrates the mask plate 7, the electrolyte plate 1, and the mask plate 8 substantially vertically, and communicates with the other end of the fuel gas passage 11 and the other end of the oxidizing gas passage 13. An oxidizing gas outlet channel 20 is provided.

In practice, the cross-sectional areas of the fuel gas passage 11 and the oxidizing gas passage 13 are as follows: the fuel gas inlet passage 17, the fuel gas outlet passage 19, the oxidizing gas inlet passage 18, and the oxidizing gas outlet passage. It is smaller than the cross-sectional area of the passage 20.

In the fuel cell having the above-described structure, the electrolyte plate 1 of each cell 15 is heated to about 600 ° C., and the fuel gas inlet passage 17 of the lowermost cell 15 of the stack 16 is heated.
When a fuel gas such as H ₂ is supplied to the fuel cell and an oxidizing gas such as air containing CO ₂ is supplied to the oxidizing gas inlet channel 18, the fuel gas flows from the fuel gas inlet channel 17 of each cell 15 to the fuel gas channel 17. The oxidizing gas flows into the oxidizing gas flow channel 13 from the oxidizing gas inlet flow channel 18 of each cell 15 and flows into the oxidizing gas flow channel 13 through the hole 4 of the punch plate 6.
From the anode 3 and the reaction carried out through the electrolyte plate 1 of each cell 15 causes the movement of carbonate ions in the electrolyte plate 1, and the electric power is generated by the potential difference generated between the anode 2 and the cathode 3, Further, the fuel gas that has passed through the fuel gas flow path 11 is discharged to the outside from the lowermost cell 15 of the stack 16 through the fuel gas outlet flow path 19, and similarly, the oxidizing gas that has passed through the oxidizing gas flow path 13 Is discharged from the lowermost cell 15 of the stack 16 to the outside via the oxidizing gas outlet flow path 20.

[0013]

However, the temperature distribution in the fuel cell constituted by each cell 15 when the above-mentioned fuel cell is in operation is determined by the reaction carried out through the electrolyte plate 1 described above. As shown in FIG. 9, as the fuel gas and the oxidizing gas flow from one end A side to the other end B side where the fuel gas and the oxidizing gas are discharged to the outside, the height increases. There is a temperature difference of about 100 ° C. with the side.

Therefore, near the other end B side of the fuel cell,
Due to the high temperature, thermal decomposition of the carbonate of the electrolyte plate 1 is likely to occur, resulting in a decrease in the carbonate, and as a result, the life of the fuel cell is shortened.

The present invention has been made to solve the above-mentioned problem, and has as its object to make the temperature distribution in a fuel cell uniform.

[0016]

According to the present invention, there is provided an anode provided on one side of an electrolyte plate and having a peripheral portion surrounded by a mask plate, and an anode provided on the other side of the electrolyte plate and having a peripheral portion provided with a mask. A cell having a cathode surrounded by a plate, a plurality of cells are stacked, and a separator having a corrugated portion is interposed between adjacent cells, and one end of the cell to the other end between the anode and the separator. A fuel gas flow path extending substantially horizontally toward the side, and an oxidizing gas flow path extending substantially horizontally from one end of the cell to the other end between the cathode and the separator, further comprising: A fuel gas passage, an oxidizing gas inlet passage that penetrates the mask plate and the electrolyte plate substantially vertically, and communicates with the upstream end of the oxidizing gas passage in the gas flow direction; In a molten carbonate fuel cell, a fuel gas flow path, a fuel gas outlet flow path communicating with the downstream end of the oxidizing gas flow direction in the gas flow direction, and an oxidizing gas outlet flow path formed substantially vertically through the plate. The fuel gas inlet flow path and the oxidizing gas inlet flow path communicate with each other separately on one end side;
The gas outlet channel and the oxidizing gas outlet channel are
Laminate multiple cells so that they communicate separately, and
Each fuel gas inlet channel, fuel gas channel, fuel gas outlet channel
Through the lower fuel gas flow path to the outside through the
Through the oxidizing gas inlet channel, oxidizing gas channel, and oxidizing gas outlet channel.
Forming a lower stack having a lower oxidizing gas flow path to the outside and a fuel gas outlet flow path and an oxidizing gas outlet flow path separately communicating at one end side , and a fuel gas inlet flow path.
And by stacking a plurality of cells oxidizing gas inlet passage at the other end to separately communicating to <br/> so that each respective fuel gas inlet passage,
Upper part reaching outside through fuel gas flow path and fuel gas outlet flow path
Each oxidizing gas inlet channel from the fuel gas distribution channel and the outside, oxidation
Upper oxidation to the outside via gas flow path and oxidizing gas outlet flow path
A fuel gas bypass forming an upper stack having a gas flow path and connecting a fuel gas inlet flow path of a cell located at the uppermost stage of the lower stack and a fuel gas inlet flow passage of a cell located at the lowermost stage of the upper stack; The flow path and the oxidizing gas inlet flow path of the cell located at the top of the lower stack are connected to the oxidizing gas inlet flow path of the cell located at the bottom of the upper stack .
That the intermediate distributor with an oxidizing gas bypass passage, is interposed between the lower stack and the top stack.

[0017]

According to the molten carbonate fuel cell of the present invention,
Approximately half of the fuel gas supplied from the
Flow from one end to the other end
Approximately half of the fuel gas supplied from the outside
Flow through the oxidizing gas flow path from one end to the other end.
You.

Also, the externally supplied and lower stack
The remaining fuel gas that did not flow into the
The gas flows from the other end to the one end.
At the outside, and does not flow into the lower stack
The remaining oxidizing gas flows through the upper stack oxidizing gas flow path at the other end.
Flows from one side to the other end, thereby
The temperature gradient is reversed between the lower and upper stacks.
You.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show one embodiment of the present invention.
In the drawing, the portions denoted by the same reference numerals as those in FIGS. 5 to 9 represent the same components.

The cell 1 which is a constituent unit of the fuel cell
5 has the same structure as that shown in FIGS.
A detailed description of the structure of No. 5 is omitted.

Reference numeral 21 denotes a fuel gas inlet passage 17, an oxidizing gas inlet passage 18 on one end A side, and a fuel gas outlet passage 19,
A lower stack 22 in which a plurality of cells 15 are stacked such that the oxidizing gas outlet passage 20 is located on the other end B side is a fuel gas outlet passage 19, the oxidizing gas outlet passage 20 is on one end A side, and the fuel gas The inlet channel 17 and the oxidizing gas inlet channel 18 are at the other end B
This is an upper stack in which a plurality of cells 15 are stacked so as to be located on the side, and an intermediate distributor 23 is interposed between a lower stack 21 and an upper stack 22.

Further, on one end A side of the separator 9b below the cell 15 located at the lowermost part of the upper stack 22, the seal portion 14 like the other separator 9 is not formed, and the separator 9b and the punch 9 The oxidizing gas channel 13b formed between the plate 6 and the plate 6 is connected to the cell 15 via a gap 30 formed between one end of the separator 9b and the mask plate 8.
Communicates with the outside world.

The intermediate distributor 23 includes partition plates 24, 25 on the upper and lower surfaces of a separator 9a having substantially the same shape as the separator 9.
The partition plate 24 is provided on the top 12a and the seal portion 14a of the corrugated plate-like portion of the separator 9a,
The partition plate 25 is provided at the bottom 10a of the corrugated plate-like portion of the separator 9a.
A fuel gas bypass channel 11a is formed between the separator 9a and the partition plate 25, and an oxidizing gas bypass channel 13a is formed between the separator 9a and the partition plate 24. Have been.

The lower surface of the partition plate 25 is in close contact with the top portion 12 and the seal portion 14 of the separator 9 above the cell 15 located at the top of the lower stack 21, and an oxidizing gas is interposed between the partition plate 25 and the separator 9. The flow path 13 is formed, and holes 26 and 2 penetrating up and down are formed on one end A side of the partition plate 25.
7, one end of the fuel gas bypass channel 11a and one end of the oxidizing gas bypass channel 13a communicate with the fuel gas inlet channel 17 and the oxidizing gas inlet channel 18 of the cell 15 located at the top of the lower stack 21. doing.

The upper surface of the partition plate 24 is in close contact with the bottom 10 and the sealing portion 14 of the separator 9b of the cell 15 located at the lowermost part of the upper stack 22, and the fuel gas is interposed between the partition plate 24 and the separator 9b. A hole 2 which forms a flow path 11b and is formed on the other end B side of the partition plate 24 and penetrates vertically.
8, 29, the fuel gas bypass channel 11a,
The other end of the oxidizing gas bypass channel 13a is
Fuel gas inlet channel 1 of cell 15 located at the bottom of
7. It communicates with the oxidizing gas inlet channel 18.

The fuel gas flow channel 11b is connected to the cell 15 via a gap 31 formed between one end of the separator 9b and the partition plate 24, similarly to the oxidizing gas flow channel 13b.
Communicates with the outside world.

Hereinafter, the operation of this embodiment will be described.

When power is generated by the fuel cell, the electrolyte plate 1 of each cell 15 is heated to a predetermined temperature, and the fuel gas inlet channel 1 of the lowermost cell 15 of the lower stack 21 is heated.
7, a fuel gas such as H ₂ , and an oxidizing gas inlet passage 18.
When an oxidizing gas such as air containing CO ₂ is supplied to the fuel cell, almost half of the fuel gas is supplied to each cell 15 constituting the lower stack 21.
Flows from the fuel gas inlet channel 17 into the fuel gas channel 11 and flows through the fuel gas channel 11 from one end A side to the other end B side. The gas flows into the oxidizing gas flow channel 13 from the gas inlet flow channel 18 and flows through the oxidizing gas flow channel 13 from one end A to the other end B, and enters into the electrolyte plate 1 by a reaction performed through the electrolyte plate 1. The movement of carbonate ions occurs, and electric power is generated by a potential difference generated between the anode 2 and the cathode 3.

Further, the fuel gas passage 11 and the oxidizing gas passage 1
The fuel gas and the oxidizing gas that have passed through
Through the fuel gas outlet flow path 19 and the oxidizing gas outlet flow path 20 of the cell 15 constituting the lower stack 21 of the lower stack 21
5 to the outside.

On the other hand, of the fuel gas and the oxidizing gas supplied to the lower stack 21, the remaining gas that has not flowed into the fuel gas passage 11 and the oxidizing gas passage 13 of each cell 15 constituting the lower stack 21 is The gas flows into the fuel gas bypass channel 11a and the oxidizing gas bypass channel 13a of the intermediate distributor 23, and flows from the one end A side to the other end B side through the fuel gas bypass channel 11a and the oxidizing gas bypass channel 13a. The fuel gas flows from the fuel gas inlet channel 17 and the oxidizing gas inlet channel 18 of each cell 15 of the stack 22 to the fuel gas channels 11 and 11b and the oxidizing gas channels 13 and 13b.
1b, the oxidizing gas passages 13 and 13b are moved from the other end B side to one end A
Flows towards the side and the electrolyte plate 1
The carbon dioxide ions move in the electrolyte plate 1 due to the reaction performed through the anode, and power is generated by the potential difference generated between the anode 2 and the cathode 3.

Further, the fuel gas and the oxidizing gas that have passed through the fuel gas passages 11 and 11b and the oxidizing gas passages 13 and 13b are:
One end A of the cell 15 located at the bottom of the upper stack 22
It is discharged to the outside from the gaps 31 and 30 formed on the side.

Therefore, in the fuel cell of this embodiment, as shown in FIG. 4, in the cells 15 constituting the lower stack 21, the temperature inside the cells 15 increases from one end A to the other end B. In the cells 15 constituting the upper stack 22, the temperature in the cells 15 tends to increase from the other end B side toward the one end A side.
The temperature gradient of the lower stack 21 and the upper stack 22 is reversed, and the temperature inside the cell 15 is lower than the temperature (about 700 ° C.) at the other end of the cell 15 of the conventional fuel cell (about 700 ° C.). C), and the temperature rise of the fuel cell is suppressed.

As described above, in the lower stack 21, the temperature rise of the portion of each cell 15 near the other end B side of the electrolyte plate 1, and in the upper stack 22, each cell 1
Since it is possible to suppress the temperature rise in the portion near the one end A side of the electrolyte plate 1 of No. 5, it is possible to prevent the reduction of the carbonate due to the thermal decomposition and extend the life of the fuel cell.

It should be noted that the molten carbonate fuel cell of the present invention is not limited to the above-described embodiment, but may be modified by changing the shape of the separator and other various changes without departing from the gist of the present invention. Of course, it can be added.

[0036]

As described above, according to the molten carbonate fuel cell of the present invention, the flow direction of the fuel gas and the oxidizing gas flowing through each cell of the lower stack, and the flow direction of each cell of the upper stack are determined. Since the flowing direction of the flowing fuel gas and the oxidizing gas is reversed by the intermediate distributor, the temperature gradient of the lower stack and the upper stack tends to be reversed, and as a result, the temperature of each cell decreases. To be averaged,
It is possible to suppress a rise in the temperature of the electrolyte plate, prevent a decrease in carbonate due to thermal decomposition, and prolong the life of the fuel cell.

[Brief description of the drawings]

FIG. 1 is a detailed view of an intermediate distributor of a molten carbonate fuel cell according to the present invention.

FIG. 2 is a view taken in the direction of arrows II-II in FIG.

FIG. 3 is an overall view of a molten carbonate fuel cell according to the present invention.

FIG. 4 is a graph showing a temperature distribution in the molten carbonate fuel cell of the present invention.

FIG. 5 is a detailed view of a conventional molten carbonate fuel cell.

FIG. 6 is a view taken in the direction of arrows VI-VI in FIG.

FIG. 7 is a plan view of a conventional molten carbonate fuel cell.

FIG. 8 is an overall view of a conventional molten carbonate fuel cell.

FIG. 9 is a graph showing a temperature distribution in a conventional molten carbonate fuel cell.

[Explanation of symbols]

 Reference Signs List 1 electrolyte plate 2 anode 3 cathode 11, 11b fuel gas flow path 11a fuel gas bypass flow path 13, 13b oxidizing gas flow path 13a oxidizing gas bypass flow path 15 cell 17 fuel gas inlet flow path 18 oxidizing gas inlet flow path 19 fuel gas Outlet channel 20 Oxidizing gas outlet channel 21 Lower stack 22 Upper stack 23 Intermediate distributor

Claims (1)

(57) [Claims] 1. An anode disposed on one side of an electrolyte plate and having a peripheral portion surrounded by a mask plate, and a cathode disposed on the other side of the electrolyte plate and having a peripheral portion surrounded by a mask plate. A plurality of provided cells are stacked, and a separator having a corrugated portion is interposed between adjacent cells and extends substantially horizontally from one end of the cell to the other end between the anode and the separator. A fuel gas flow path, and an oxidizing gas flow path extending substantially horizontally from one end of the cell to the other end between the cathode and the separator, and further, the mask plate and the electrolyte plate are substantially vertically The fuel gas flow path, the fuel gas inlet flow path communicating with the gas flow direction upstream end of the oxidizing gas flow path, the oxidizing gas inlet flow path, the mask plate, the electrolyte plate substantially perpendicularly penetrates the fuel In a molten carbonate fuel cell formed with a gas flow path, a fuel gas outlet flow path communicating with the downstream end of the oxidizing gas flow direction in the gas flow direction, and an oxidizing gas outlet flow path,
Fuel gas inlet passage and the oxidizing gas inlet passage which at one end side
The fuel gas outlet flow path and the oxidizing gas output
A plurality of cells are stacked so that the mouth flow path communicates separately on the other end side, and each fuel gas inlet flow path, fuel gas
Lower fuel gas that reaches the outside through the
Flow paths and external oxidizing gas inlet channels, oxidizing gas flows
Oxidizing gas flow to the outside through the passage and oxidizing gas outlet channel
And a fuel gas outlet flow path and an oxidizing gas outlet flow path are separately connected at one end side.
The other end of the fuel gas inlet passage and the oxidizing gas inlet passage
A plurality of cells are stacked so as to communicate with each other separately on each side, and each fuel gas inlet passage, fuel gas passage, fuel gas outlet
Upper fuel gas flow path to the outside via the flow path and from outside
Each oxidizing gas inlet channel, oxidizing gas channel, oxidizing gas outlet channel
Forming an upper stack having an upper oxidizing gas flow path extending to the outside through a fuel gas inlet flow path of a cell located at the uppermost stage of the lower stack and a fuel gas inlet flow path of a cell located at the lowermost stage of the upper stack. A fuel gas bypass flow path connecting the passages, and an oxidizing gas bypass flow path connecting the oxidizing gas inlet flow path of the cell located at the top of the lower stack and the oxidizing gas inlet flow path of the cell located at the bottom of the upper stack Be prepared
A molten carbonate fuel cell, wherein the obtained intermediate distributor is interposed between the lower stack and the upper stack.