JP3252473B2 - 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 fuel cell used in the energy sector for converting chemical energy of a fuel into electric energy, and more particularly, to a structure in which cells are stacked in multiple layers using an intermediate holder. It relates to a fuel cell.

[0002]

2. Description of the Related Art Among fuel cells, a molten carbonate type fuel cell includes, as shown in FIG. 3, an electrolyte plate 1 in which a molten carbonate is impregnated into a porous material as an electrolyte, and a cathode (oxygen electrode). A cell C sandwiched between both electrodes of an anode 2 and an anode (fuel electrode) 3 to supply the oxidizing gas OG to the cathode 2 and the fuel gas FG to the anode 3 is referred to as one cell C. C is laminated via a separator 4 to form a stack. Reference numeral 5 denotes a mask plate in which a central portion serving as an electrode position is cut out to form only a peripheral portion.
Is a punch plate used to uniformly contact the electrode with the electrolyte plate 1.

As shown in FIG. 3, an internal manifold type of the above-mentioned molten carbonate fuel cell has a manifold for supplying an oxidizing gas OG on one side of an electrolyte plate 1, a mask plate 5 and a separator 4. As shown in FIG. 7 and a fuel gas FG supply manifold 8 are provided, and an oxidizing gas OG discharge manifold 9 and a fuel gas FG discharge manifold 10 are provided on opposite peripheral portions, and are formed on both front and back surfaces of the separator 4. The oxidizing gas OG and the fuel gas FG are caused to flow in a parallel flow along the gas passage 11.

In order to obtain a high output with the fuel cell having such a structure, when the number of stacked cells C is increased to increase the number of stacked cells, as shown in FIG. And stack 13 sandwiched between 13 and 13
Is placed on the lower bolster 15, and on the upper holder 12, a metal bellows 16 having a large elongation is mounted so as to follow a large shrinkage of the stack S during the impregnation process performed after assembling the fuel cell. An upper bolster 14 is disposed thereon, and the upper and lower bolsters 14 and 15 are tightened by a tightening rod 17 and a nut 18 so that a predetermined tightening force is applied to the stack S via the bellows 16. Is common.

[0005]

However, in the case of a fuel cell having a high stack as shown in FIG. 4, as the number of stacked cells increases, the tightening surface pressure between the upper layer and the lower layer increases the weight of the stack S itself. In the lower layer, the clamping surface pressure increases in the lower layer, and the creep phenomenon of the electrode becomes severe, which adversely affects the battery life, and the gas distribution to the cells in each stage becomes uneven. This may cause problems such as uneven battery performance.

[0006] In order to solve the above-mentioned problems caused by the high stacking of the stack, the present invention provides an intermediate holder at an intermediate portion of the stack and fixedly supports the intermediate holder. To reduce the difference in tightening surface pressure between the upper and lower layers, improve the flow distribution performance in the upper and lower cells, and help increase the temperature for degreasing and impregnation before starting operation of the fuel cell It is an object of the present invention to provide a fuel cell capable of performing the above.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a peripheral part of an internal manifold type fuel cell on one side and the other side of a thick intermediate holder body. The oxidizing gas and fuel gas supply / discharge manifolds are provided to be open in the vertical direction so as to be able to communicate with the oxidizing gas and fuel gas supply / discharge manifolds provided on the other side and the oxidizing gas and the oxidizing gas. The oxidizing gas supply side and discharge side headers and the fuel gas supply side and discharge side header are connected to the supply / discharge manifold and the fuel gas supply / discharge manifold, respectively. An intermediate holder formed by inserting and arranging a plurality of heater pins at the center in the thickness direction is supported and fixed by legs, and the upper stack and the lower stack are divided into upper and lower sides on both sides of the intermediate holder. Week The oxidizing gas and fuel gas supply / discharge manifolds provided on one side and the other side of the unit are arranged in direct contact with the intermediate gas supply / discharge manifolds of the intermediate holder so as to match the respective oxidant gas / fuel gas supply / discharge manifolds. So that gas can be supplied from the intermediate holder to the upper and lower stacks, and the upper holder, bellows, and upper bolster are placed on the upper stack in order, and the upper end of the tightening rod fixed to the intermediate holder Into the upper bolster, screw the nut, and arrange the lower holder, bellows, and lower bolster under the lower stack in order, and insert the lower end of the tightening rod fixed to the intermediate holder through the lower bolster. Screw the nut, and tighten the upper rod between the upper bolster and the intermediate holder using the tightening rods and nuts. Each lower stack a configuration which is adapted provide a clamping force between the.

[0008]

[Function] The weight of the stack can be supported by supporting and fixing the intermediate holder as a thick plate with legs, and the stack is divided vertically and supported by the intermediate holder, so the upper layer of the stack Since the difference between the clamping surface pressures of the upper and lower layers can be reduced, and gas is supplied and discharged from the intermediate holder to the upper and lower stacks, it is possible to eliminate uneven gas distribution. Further, the temperature rise in the battery during degreasing and impregnation can be assisted by heating with a heater. At this time, since the insertion position of the heater pin is the center in the thickness direction (vertical direction), it is symmetrical in the vertical direction. The temperature can be raised, and the deformation of the intermediate holder itself can be prevented.

[0009]

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

FIGS. 1 and 2 show an embodiment of the present invention. Similar to the embodiment shown in FIGS. 3 and 4, an electrolyte plate 1 is sandwiched between both electrodes of a cathode 2 and an anode 3 from both sides. The intermediate cell is sandwiched at an intermediate position of the stack S configured by stacking the resulting cells in multiple layers with the separator 4 interposed therebetween, and the stack is divided into an upper stack S1 and a lower stack S2 to be supported.

The intermediate holder 19 is provided with an oxidizing gas supply manifold 7 and a fuel gas supply manifold 8 alternately arranged on one side of a peripheral portion of an intermediate holder body 20 formed by forming a thick plate into a rectangular shape. At the same time, on the other side of the peripheral portion, oxidizing gas discharge manifolds 9 and fuel gas discharge manifolds 10 are alternately arranged, and the oxidizing gas supply manifolds 7 and the discharge manifolds 9 are provided.
Are connected to the oxidizing gas supply side header 21 and the oxidizing gas supply side header 22 via communication passages 25 and 26, respectively, and are connected to the fuel gas supply manifold 8 and the discharge gas manifold. Reference numeral 10 denotes a fuel gas supply-side header 23 and a fuel gas supply-side header 24, which are connected separately via communication passages 27 and 28, respectively. Fuel gas is
The supply manifolds 7 and 8 are distributed to the upper and lower sides of the intermediate holder main body 20. On the discharge side, the oxidizing gas and the fuel gas are supplied from the upper and lower sides of the intermediate holder main body 20 to the respective discharge manifolds 9 and 10 respectively. And are guided to the discharge side headers 22 and 24, respectively.

A central portion of the intermediate holder body 20;
That is, the heater pins 29 for raising the temperature can be inserted into the area corresponding to the battery reaction section at the center of the stacks S1 and S2. A plurality of heater pin holes 30 are formed in the width direction in parallel at the center portion of the intermediate holder body 20 in the thickness direction, and the heater pins 29 are inserted into the respective heater pin holes 30. The intermediate holder body 20 is prevented from being thermally deformed due to symmetrical heat transfer.

When the stack is to be supported by using the intermediate holder 19 configured as described above, as shown in an example in FIG. 2, the intermediate holder 19 is provided with legs 31 so that it can be fixed on the floor. The upper stack S1 and the lower stack S2 which are divided on the upper and lower sides with the intermediate holder 19 interposed therebetween, and the manifolds 7, 8, 9, 10 in the peripheral portion as shown in FIG. , 10 on the upper stack S1, the upper holder 12, the metal bellows 1
6. Place the upper bolster 14 in order and place the intermediate holder 1
The upper end of a tightening rod 17a having a lower end fixed to 9 is inserted through the upper bolster 14, and a nut 18 is screwed into the upper rod S1 so as to apply a tightening force to the upper stack S1 with the tightening rod 17a and the nut 18. Similarly, in the lower stack S2, the lower bolster 15 is sequentially disposed below the lower stack S2 via the lower holder 13 and the bellows 16, and the intermediate holder 1
The lower end of the tightening rod 17b whose upper end is fixed to 9 is inserted through the lower bolster 15, the nut 18 is screwed, and the lower stack S2 is tightened by tightening the nut 18 with the tightening rod 17b. To do.

When the intermediate holder 19 is placed between the stacks S1 and S2 as shown in FIG. 2 and both stacks S1 and S2 are supported by the intermediate holder 19, each of the stacks S1 and S2 can be assembled before starting operation of the fuel cell. A degreasing process for removing organic substances added when manufacturing the electrolyte plates 1 of each cell in the stacks S1 and S2, and an impregnation process for melting and impregnating the electrolyte plates 1 with carbonates are performed. Such degreasing and impregnating treatments are performed by raising the temperature inside the battery while flowing an inert gas or the like into the battery. However, it is possible to raise the temperature of the upper and lower stacks S1 and S2 by a heater disposed at the center position of the intermediate holder 19. As a result, the heater can be used to assist in initial degreasing and temperature rise for impregnation. At this time, since the heater pin 29 is located at the center of the intermediate holder 19, heat is transmitted symmetrically in the vertical direction. As a result, there is no temperature difference between the upper and lower parts, and the intermediate holder 19 itself is not likely to be thermally deformed.

When the operation of the fuel cell is started, the oxidizing gas and the fuel gas are guided to the supply manifolds 7 and 8 (see FIG. 3) of the respective stacks S1 and S2 so as to be supplied to the cathode 2 side and the anode 3 side. However, the intermediate holder 19
The manifolds 7 for supplying and discharging oxidizing gas and fuel gas
8, 9, and 10, which are connected to the headers 21, 23 and 22, 24 on the supply side and the discharge side, respectively, so that the gas is supplied from the intermediate holder 19 to the upper stack S 1 and the lower stack S 2. Discharge can be performed, and the gas distribution performance can be improved as compared with the case where gas is supplied and discharged from one of the upper and lower stacks S1 and S2 to the other. In this case, each communication channel 25,
The flow distribution performance can be controlled by changing the diameter of 26, 27, 28.

The present invention is not limited to the above-described embodiment.
Although the case where all of the components 3 and 24 are arranged outside the intermediate holder main body 20 and connected by the communication flow paths 25, 26, 27 and 28 is illustrated, a hole is formed inside the peripheral portion of the intermediate holder main body 20 to form a hole. It may be used as a header, the intermediate holder of the present invention may be used as upper and lower holders, and the intermediate holder may be supported using the fastening rod 17b without using the leg 31. Good, furthermore, the intermediate holder is not supported, and a structure in which the lower fastening bellows 16 is eliminated without fixing the fastening rod by the intermediate holder portion may be employed. Of course, various changes can be made.

[0017]

As described above, according to the fuel cell of the present invention, one side of the peripheral portion of the intermediate holder main body formed as a thick plate and the other side of the peripheral portion of the internal manifold type fuel cell are provided. The oxidizing gas and fuel gas supply / discharge manifolds are provided to be open in the vertical direction so as to be able to communicate with the oxidizing gas / fuel gas supply / discharge manifolds provided on the other side, and the oxidizing gas supply / discharge is provided. The exhaust manifold and the fuel gas supply / discharge manifold are connected to the oxidizing gas supply side and discharge side headers, and the fuel gas supply side and discharge side headers, respectively, and further at an inner position than the manifold position and An intermediate holder, in which a plurality of heater pins are inserted and arranged at the center in the thickness direction, is fixed by supporting with legs, and the upper stack and the lower stack, which are divided into upper and lower sides on both sides of the intermediate holder, are separated into peripheral parts. One And the oxidizing gas and fuel gas supply / discharge manifolds provided on the other side are arranged in direct contact with the oxidizing gas and fuel gas supply / discharge manifolds of the intermediate holder so as to match the intermediate holder. The upper holder, the bellows, and the upper bolster are placed on the upper stack in this order, and the upper end of the tightening rod fixed to the intermediate holder is placed on the upper bolster. Insert and screw the nut together, and the lower holder under the lower stack,
Bellows and lower bolster are arranged in order, the lower end of the tightening rod fixed to the intermediate holder is inserted through the lower bolster, and nuts are screwed together. In the upper stack,
In addition, since the tightening force is applied to the lower stack between the lower bolster and the intermediate holder, the difference in tightening surface pressure between the upper layer and the lower layer of the stack can be reduced by half or further reduced. In addition, the gas can be flowed evenly in the lower layer part, and the gas is supplied from the intermediate holder to the upper and lower stacks, so that the flow distribution performance can be improved, and the battery performance can be more evenly maintained.
Furthermore, since a heater pin is inserted and arranged in the center of the intermediate holder to heat the stack, it can be used for degreasing and raising the temperature for impregnation after assembling the fuel cell. Because it is located in the center of the intermediate holder, there is no temperature difference between the upper and lower parts, preventing thermal deformation.The intermediate holder is made of thick plate and has rigidity, so it is supported and fixed with legs and moves up and down. And the like can be supported.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of an intermediate holder used for a fuel cell according to the present invention.

FIG. 2 is a schematic side view of the fuel cell of the present invention.

FIG. 3 is an exploded perspective view showing a part of the fuel cell.

FIG. 4 is a schematic side view showing a state where a highly stacked fuel cell is tightened.

[Explanation of symbols]

 7 Manifold for oxidizing gas supply 8 Manifold for fuel gas supply 9 Manifold for oxidizing gas discharge 10 Manifold for fuel gas discharge 17 a, 17 b Tightening rod 19 Intermediate holder 20 Intermediate holder main body 21 Header for oxidizing gas supply 22 Oxidizing gas discharging side Header 23 Fuel gas supply side header 24 Fuel gas discharge side header 25, 26, 27, 28 Communication flow path 29 Heater pin 31 Leg S1 Upper stack S2 Lower stack

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-309564 (JP, A) JP-A-61-161667 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 8/24 H01M 8/04

Claims (1)

(57) [Claims] 1. An oxidizing gas and a fuel gas provided on one side and the other side of a peripheral part of an internal manifold type fuel cell on one side and the other side of a peripheral part of an intermediate holder body made of a thick plate. In order to be able to communicate with the supply / discharge manifold, each supply / discharge manifold for the oxidizing gas and the fuel gas is provided to be opened in the vertical direction, and the supply / discharge manifold for the oxidizing gas and the supply / discharge manifold for the fuel gas are respectively provided. Connect the header on the supply side and discharge side of the oxidizing gas and the header on the supply side and discharge side of the fuel gas, and further insert and arrange a plurality of heater pins inside the manifold position and at the center in the thickness direction. The intermediate holder is supported and fixed by the legs, and the upper and lower stacks divided on the upper and lower sides of the intermediate holder are separated from the oxidizing gas provided on one side and the other side of the peripheral part. Fuel gas Each supply / discharge manifold can be arranged in direct contact with the supply / discharge manifold for the oxidizing gas and fuel gas of the intermediate holder so that gas can be supplied from the intermediate holder to the upper and lower stacks. Place the upper holder, bellows, and upper bolster on the upper stack in this order, insert the upper end of the tightening rod fixed to the intermediate holder into the upper bolster, screw the nut, and lower the lower stack. Side, a lower holder, a bellows, and a lower bolster are arranged in this order. Tighten the upper stack between the intermediate holders and the lower stack between the lower bolster and the intermediate holder. Fuel cell characterized by.