JPH1131517A - Phosphoric acid fuel cell - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent scattering of phosphoric acid evaporated on the fuel electrode side, to effectively recover and reuse the phosphoric acid, and to stably operate for a long time. A matrix containing phosphoric acid, a fuel electrode,
A plurality of single cells each composed of the air electrode 3 and the porous carbon plates 4A and 5 are stacked via a separator 7 and further stacked via a cooling plate 6 to form a fuel cell stack. Gas supply manifold 10, fuel gas discharge manifold 11, air supply manifold 1
2. An air discharge manifold 13 is provided to supply and discharge fuel gas and air. The end 4a of the porous carbon plate 4A disposed on the fuel electrode side is connected to the fuel gas discharge manifold 11
The phosphoric acid is condensed and recovered while keeping the temperature low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a phosphoric acid fuel cell, and more particularly to a structure for holding phosphoric acid in a fuel cell stack.

[0002]

BACKGROUND ART Fuel cells, high efficiency, since almost no generation of pollution-causing substances, such as NO _X, large expectations for future petroleum alternative energy. Above all, a phosphoric acid fuel cell using phosphoric acid as an electrolyte is at a stage near the most practical stage. FIG. 5 is a perspective view showing a basic configuration of a phosphoric acid type fuel cell. As shown in the figure, a fuel electrode 2 and an air electrode 3 are arranged on both main surfaces of a rectangular plate-like matrix 1 containing phosphoric acid, and a fuel gas facing the fuel electrode 2 is further provided on the outer surface thereof. A single cell, which is a basic structural unit, is constituted by arranging a porous carbon plate 4 having a flow groove and a porous carbon plate 5 having an air flow groove facing the air electrode 3. Usually, the matrix 1 is formed from a porous material mainly composed of silicon carbide. The anode 2 is formed by binding the anode catalyst layer to the anode substrate, and the cathode 3 is formed by binding the cathode catalyst layer to the cathode substrate. It is made of a porous material as a main component. Further, the porous carbon plate 4 and the porous carbon plate 5 generally have a function of storing and retaining phosphoric acid used in the matrix 1 in addition to a function of supplying fuel gas or air. The unit cell thus constructed has a thickness of several mm and a side length of 600 to 1000 mm.

In this configuration, when fuel gas is supplied to the fuel gas flow grooves of the porous carbon plate 4 and air is supplied to the air flow grooves of the porous carbon plate 5, the fuel gas diffuses in the fuel electrode base material. To the anode catalyst layer, and air diffuses through the air electrode base material and reaches the cathode catalyst layer,

[0004]

The reaction of H ₂ → 2H + 2e ⁻ ; fuel electrode 2H ⁻ + (1/2) O ₂ + 2e ⁻ → H ₂ O; air electrode occurs, and current is taken out to an external circuit. However, since the output voltage obtained from the single cell as described above is as low as about 0.6 V, the single cell is generally laminated as shown in FIG. 5 with a separator 7 made of conductive and gas-impermeable glassy carbon interposed. Connected electrically in series to increase the output voltage. In order to form the laminated structure as described above, the cooling plate 6 is interposed for each laminated block composed of 5 to 6 single cells, and the cooling plate 6 is moved from the cooling water inlet 8 to the cooling water outlet 9. By flowing cooling water through a cooling pipe buried in the inside, the laminated block is cooled, the heat generated due to the above reaction is removed, the temperature is kept at a constant temperature, and the heat energy is recovered.

[0005] As shown in FIG. 5, a fuel cell stack obtained by stacking a plurality of stacking blocks with a cooling plate 6 interposed therebetween is provided with two opposing side surfaces connected to fuel gas flow grooves. The gas supply manifold 10 and the fuel gas discharge manifold 11 are mounted on two opposing side surfaces connected to the air flow groove.
3 and the fuel gas and the air are supplied to the stacked body using these manifolds to generate electric power.

[0006]

In order to put a phosphoric acid fuel cell to practical use, it is necessary to guarantee a life of 40,000 to 50,000 hours. However, in a phosphoric acid fuel cell, the phosphoric acid retained in the matrix evaporates and scatters with the operation, so that effective supplementation of phosphoric acid is an essential condition for continuing operation for a long time. For this reason, in the conventional phosphoric acid type fuel cell, a method of individually supplying phosphoric acid from the outside to each unit cell is generally used, but there is no means for accurately measuring the amount of phosphoric acid retained in each unit cell. Further, inside the stacked fuel cells, the temperature of the single cell adjacent to the cooling plate is low, and the temperature of the single cell in the central portion away from the cooling plate becomes relatively high, and phosphoric acid is generated by each single cell. Since there is a difference in the reduction rate, it has been impossible to grasp the amount of phosphoric acid scattered in each single cell and supply an appropriate amount of phosphoric acid over a long period of time without excess or deficiency.

[0007] The phosphoric acid type fuel cell shown in FIG.
It is configured to reduce the amount of phosphoric acid that evaporates in consideration of the above difficulties. That is, in the present configuration, as shown in the plan view of FIG. 6, the cooling water pipe buried in the cooling plate 6 is provided at the outlet side of the air flow groove of the stacked body of the cells 18, that is, at one end on the downstream side of the air. A cooling water inlet is provided at a corresponding position, and an outlet is provided at the inlet side of the air flow groove, that is, at a position corresponding to one end on the upstream side of the air, so that the air flows sequentially from the downstream side to the upstream side. Have been. Therefore, the in-plane temperature of the single cell should have a temperature distribution such that the downstream side of the air has a low temperature as indicated by a low temperature region 18a in the figure and the upstream side of the air has a high temperature as indicated by a high temperature region 18b. Becomes On the other hand, as shown in FIG. 7, the concentration of phosphoric acid contained in the exhaust gas is determined by the temperature of the exhaust gas, and increases exponentially as the temperature increases. When the temperature is lowered, the amount of phosphoric acid taken out with the exhaust air, that is, the amount of phosphoric acid scattered to the outside can be reduced, so that the operable time can be extended.

However, even in this configuration, FIG.
As can be seen from the flow of the fuel gas, the temperature of the downstream portion is lower only in the downstream portion of the air, and the same downstream portion has a higher temperature in the upstream portion of the air. Therefore, although the amount of exhaust gas of fuel gas is as small as about 1/6 compared with air,
As already shown in FIG. 7, the concentration in the exhaust gas increases exponentially with increasing temperature, so that the amount of phosphoric acid scattered with the fuel gas rises to a nonnegligible amount and hinders long-term operation of the phosphoric acid type fuel cell. This is a factor.

In addition, in the above-described structure shown in FIGS. 5 and 6, as described above, the air and the fuel gas are made to flow perpendicularly from one side surface of the stacked body to the opposite side surface, that is, the cross-flow system. In recent years, a return flow type flow configuration has often been used as an effective flow configuration to avoid the occurrence of local high potential in the plane and to prevent catalyst deterioration and separator corrosion. Used. FIG. 8 is a cross-sectional view of a fuel cell stack showing an example of the flow path configuration of the return flow method. The configuration of the fuel gas flow grooves and air flow grooves of each stacked cell is the same as that of the cross flow method in the return flow method. However, in the return flow method, the gas is recirculated through these flow grooves. You. In this configuration example, the partition plates 16
Gas supply manifold 10 kept airtight by
An inlet-side manifold consisting of A and an intermediate manifold 15 is provided, and an outlet-side manifold consisting of a fuel gas discharge manifold 11A and an intermediate manifold 14, which are airtightly held by partition plates 16 on opposite sides. The fuel gas supplied from the fuel gas supply manifold 10A flows through the fuel gas flow groove opened in the present manifold and is sent to the intermediate manifold 14, and the fuel gas flow groove opened in the intermediate manifold 14 and the intermediate manifold 15 The fuel gas is returned to the intermediate manifold 15 through the fuel gas discharge manifold 11A, and further discharged through the fuel gas flow groove opened in the fuel gas discharge manifold 11A.

The structure of the present return flow system is effective for avoiding the generation of a local high potential in the plane, or for preventing the deterioration of the catalyst and the corrosion of the separator. Since the inside of the cell having a high temperature and the manifold having a low temperature flow repeatedly, the phosphoric acid evaporated in the cell is cooled on the wall surface of the intermediate manifold, and a large amount of phosphoric acid is condensed. For this reason, the amount of phosphoric acid taken out of the cell from the fuel exhaust gas is several times larger than the amount taken out by the cross-flow method, which is a major factor that hinders long-time operation.

The present invention has been made in consideration of the situation of the prior art as described above, and suppresses the scattering of phosphoric acid that evaporates on the fuel electrode side of each cell of the fuel cell stack, thereby effectively recovering the fuel cell. An object of the present invention is to provide a phosphoric acid fuel cell that can be reused and operated stably for a long period of time.

[0012]

In order to achieve the above object, the present invention provides: (1) a fuel electrode in which a catalyst layer is bound to a surface of a rectangular flat matrix containing a phosphoric acid electrolyte in contact with the matrix; A porous carbon plate having a fuel gas flow groove on the outer surface of the fuel electrode, and an air flow groove orthogonal to the fuel gas flow groove on the outer surface of the air electrode. A plurality of unit cells each including a porous carbon plate are stacked via a gas-impermeable separator to form a stacked block, and the stacked blocks are alternately stacked with a cooling plate to form a substantially rectangular parallelepiped fuel cell. A laminate is formed, and a fuel gas supply manifold is provided on one of two sides facing the extending direction of the fuel gas flow groove, a fuel gas discharge manifold is provided on the other side, and an air supply manifold is provided on one of the remaining sides. On one side An air discharge manifold is provided, fuel gas is supplied from the fuel gas supply manifold, and the fuel gas is passed through the fuel gas flow groove to discharge used fuel gas from the fuel gas discharge manifold, and air is supplied from the air supply manifold. Then, in a phosphoric acid type fuel cell in which the used air is discharged from the air discharge manifold by flowing through the air flow groove and power is generated by an electrochemical reaction, the porous carbon plate provided with the fuel gas flow groove is provided. Is projected to the inside of the fuel gas discharge side manifold.

(2) Further, a square plate-like matrix containing a phosphoric acid electrolyte is sandwiched between a fuel electrode having a catalyst layer bonded to a surface in contact with the matrix and an air electrode, and a fuel gas is passed through the outer surface of the fuel electrode. A porous carbon plate with grooves is arranged, and a plurality of single cells each having a porous carbon plate with air flow grooves arranged on the outer surface of the air electrode are laminated via a gas impermeable separator. A laminated block is formed, and the laminated block is alternately laminated with the cooling plate to form a substantially rectangular parallelepiped fuel cell laminate, and a pair of fuels is provided on two side surfaces facing the extending direction of the fuel gas flow grooves. A gas manifold is provided, with a fuel gas supply manifold, at least one intermediate manifold, and a fuel gas exhaust manifold disposed on one of the gas manifolds, and an air supply manifold on one of the remaining sides of the fuel cell stack. An air discharge manifold is provided on one side, fuel gas is supplied from the fuel gas supply manifold, the fuel gas flows through a part of the fuel gas flow groove, and is sent to the intermediate manifold. After flowing through the gas flow groove, it is sent to the fuel gas discharge manifold to discharge the used fuel gas, air is supplied from the air supply manifold, and is flowed through the air flow groove to be discharged from the air discharge manifold. In a phosphoric acid fuel cell that discharges used air and generates power by an electrochemical reaction, the end of the porous carbon plate provided with the fuel gas flow groove is projected into the intermediate manifold of the fuel gas manifold. And distribute them.

(3) Further, in the phosphoric acid type fuel cell according to the above (2), an end face of the porous carbon plate protruding into the intermediate manifold of the fuel gas manifold is contacted with
A flow path forming plate made of an electrically insulating material extending in the stacking direction is provided, and a fuel gas passage is formed between the flow path forming plate and the protruding portions of two porous carbon plates adjacent in the stacking direction. It shall be.

As described in (1) above, the end of the porous carbon plate provided with the fuel gas passage groove of each cell of the phosphoric acid type fuel cell is
If it is arranged to protrude into the fuel gas discharge side manifold, the end protruding into the manifold having a lower temperature than the inside of the cell where the electrochemical reaction occurs is cooled, so that the porous carbon plate, especially the fuel The downstream side of the gas is kept at a low temperature. Therefore, the phosphoric acid evaporated in the cell and contained in the fuel gas and carried to the downstream side is effectively condensed and recovered at the downstream end of the fuel gas maintained at a low temperature and in the vicinity thereof. In addition, the amount of phosphoric acid scattered and discharged to the outside is reduced.

Further, in the phosphoric acid fuel cell of the return flow type in which an intermediate manifold is provided in the fuel gas manifold and the fuel gas is recirculated and flows as described in the above (2), the fuel gas flow groove of each cell is formed. If the end of the provided porous carbon plate is arranged to protrude into the intermediate manifold, the porous carbon plate is cooled by the end protruding into the intermediate manifold having a relatively low temperature. . Therefore, the phosphoric acid evaporated in the cell and contained in the fuel gas and carried to the downstream side is effectively condensed and recovered at the downstream end of the fuel gas maintained at a low temperature and in the vicinity thereof. In addition, the amount of phosphoric acid scattered to the outside is reduced.

Further, as in the above (3), in the above-mentioned phosphoric acid type fuel cell, further, in contact with the end face of the porous carbon plate projecting into the inside of each intermediate manifold,
A flow path forming plate made of an electrically insulating material extending in the laminating direction is provided, and a fuel gas path is formed between the flow path forming plate and the protruding portions of two adjacent porous carbon plates in the laminating direction. In this case, since all the fuel gas flowing through the cell flows through the passage of the fuel gas, the condensation of the phosphoric acid evaporated in the cell is limited to the inside of the cell and the above-described passage of the fuel gas. Can be Since the phosphoric acid condensed in the passage is returned to the inside of the cell again through the porous carbon plate, scattering of the phosphoric acid in the intermediate manifold is prevented.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

<Embodiment 1> FIG. 1 shows a first embodiment of the phosphoric acid fuel cell of the present invention.
FIG. 2 is a perspective view showing a basic configuration of the embodiment. In this figure, components having the same functions as those of the configuration of the conventional example shown in FIG. 5 are denoted by the same reference numerals, and redundant description will be omitted.

The difference between the present embodiment and the conventional example lies in the structure of the porous carbon plate on the fuel electrode side used in each cell constituting the fuel cell stack. As shown in the figure, the high quality carbon plate 4A is characterized in that the downstream end of the fuel gas projects a few cm into the inside of the fuel gas discharge manifold 11. In this configuration, the fuel gas discharge manifold 1 of the porous carbon plate 4A
The protruding portion into the inside of the fuel cell 1 does not generate heat because it does not form a battery, and the temperature inside the fuel gas discharge manifold 11 is about 20 ° C. lower than that of the cell portion. Therefore, not only the protruding portion but also the internal portion of the cell connected thereto is cooled. According to the study results of the present inventors, it is found that the fuel gas passes through the cell in a state almost equal to the allowable concentration of phosphoric acid at the temperature near the outlet. Since the acid concentration is reduced to about 1/2, the phosphoric acid in the fuel gas can be effectively recovered by cooling the downstream side of the gas passage as in the present embodiment.

<Embodiment 2> FIG. 2 is a perspective view showing a basic structure of a phosphoric acid type fuel cell according to a second embodiment of the present invention.
Also in this figure, components having the same functions as those of the configuration of the conventional example shown in FIG. 5 are denoted by the same reference numerals, and redundant description will be omitted. In the present embodiment, the fuel gas supply manifold 1 is partitioned by a partition plate 16A on the fuel gas inlet side.
The present invention is applied to a phosphoric acid fuel cell of a return flow type in which 0A and an intermediate manifold 15 are provided, and a fuel gas discharge manifold 11A and an intermediate manifold 14 partitioned by a partition plate 16B on the fuel gas outlet side. The porous carbon plate 4B on the fuel electrode side of each stacked cell
A projection 4b projecting a few cm into the intermediate manifold 14, and a few c into the interior of the intermediate manifold 15.
It is characterized by having a protruding portion 4c that protrudes m.

In this configuration, the protruding portions 4b and 4c protruding from the low temperature intermediate manifolds 14 and 15 are cooled and the temperature on the downstream side of the fuel gas decreases, so that the phosphoric acid in the fuel gas is effectively condensed. , Will be collected. <Embodiment 3> FIG. 3 shows a third embodiment of the phosphoric acid fuel cell of the present invention.
FIG. 2 is a perspective view showing a basic configuration of the embodiment. FIG.
FIG. 1 is a cross-sectional view of a fuel cell stack showing a fuel gas flow path configuration in the present embodiment. In this embodiment, as shown in FIG. 3, in addition to the configuration of the second embodiment, the end face of the protruding portion 4a of the porous carbon plate 4B on the fuel electrode side protruding into the intermediate manifold 14 is provided. Forming plate 17B made of polytetrafluoroethylene extending in the laminating direction in contact with
2 adjacent to the flow path forming plate 17B in the laminating direction.
An end face of the protruding portion 4c of the porous carbon plate 4B on the fuel electrode side, which forms a fuel gas passage between the protruding portion 4b of the plurality of porous carbon plates 4B and protrudes into the intermediate manifold 15 And a flow path forming plate 17A made of polytetrafluoroethylene extending in the laminating direction, and two porous carbon plates 4B adjacent to the flow path forming plate 17A in the laminating direction.
Is characterized in that a fuel gas passage is formed between the fuel gas passage and the projection 4c.

In this configuration, as shown in FIG. 4, the fuel gas supplied from the fuel gas supply manifold 10A passes through a high-temperature portion corresponding to the upstream side of the air in the cell 18, and a large amount of phosphoric acid The fuel containing the steam is sent to the fuel gas passage formed between the flow path forming plate 17B of the intermediate manifold 14 and the protruding portion 4b of the two porous carbon plates 4B adjacent in the laminating direction. Reflux to 18.
In the conventional return-flow fuel cell, the fuel gas is cooled by contacting the wall of the low-temperature intermediate manifold, and phosphoric acid condenses on the wall and the like. Since phosphoric acid condenses in the passage, phosphoric acid is absorbed by the porous carbon plate 4B and returned to the cell 18 by capillary force. Returning to the cell 18 again, the fuel gas that has passed through the high-temperature portion corresponding to the midstream portion of the air is similarly discharged from the two porous carbon plates 4B adjacent to the flow passage forming plate 17A of the intermediate manifold 15 in the stacking direction. Since the fuel gas flows through the passage of the fuel gas formed between the fuel cell and the protrusion 4c, phosphoric acid is supplied to the cell 1 in this section.
There is no danger of scattering outside of 8. Intermediate manifold 1
The fuel gas sent three times into the cell 18 through the fuel gas passage of No. 5 passes through the downstream portion of the low-temperature air.
The fuel gas is discharged to the fuel gas discharge manifold 11A at a low temperature. Therefore, the amount of the phosphoric acid taken out together with the exhaust gas is taken out by the phosphoric acid concentration equilibrated to the low temperature, and is reduced to a fraction of that in the conventional example.

In this embodiment, the return flow system in which the fuel gas is recirculated twice is employed. However, the number of recirculations is not limited to two, and the recirculation may be performed once or three or more times. It is easily inferred that the effect of (1) is obtained.
In this embodiment, the flow path forming plates 17A and 17B are made of a polytetrafluoroethylene plate. In addition, a metal plate coated with polytetrafluoroethylene or a metal plate with a polytetrafluoroethylene sheet interposed is used. It may be a plate.

[0024]

As described above, in the present invention, (1) the phosphoric acid type fuel cell is configured as described in claim 1, so that it is connected to the protruding portion of the fuel gas discharge manifold. The temperature on the downstream side of the porous carbon plate is kept at a low temperature, and phosphoric acid evaporated in the cell and transported to the downstream side is effectively condensed, recovered and reused, so it is stable for a long time A phosphoric acid type fuel cell which can be operated at a low temperature can be obtained.

(2) According to the second aspect of the present invention, in the phosphoric acid type fuel cell having the flow path configuration of the return flow system, the projecting portion projecting into the intermediate manifold also provides the fuel cell. Since the temperature on the downstream side of the porous carbon plate is kept at a low temperature and the phosphoric acid is effectively condensed, recovered and reused, stable operation can be performed for a long period of time.

(3) If the phosphoric acid type fuel cell having the flow path structure of the return flow system is configured as described in claim 3, the evaporated phosphoric acid is discharged into the intermediate manifold. It is transported to the downstream side together with the fuel gas in the closed flow path without being condensed, and is effectively condensed, recovered and reused in the downstream part. It is suitable.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a basic configuration of a first embodiment of a phosphoric acid fuel cell according to the present invention.

FIG. 2 is a perspective view showing a basic configuration of a second embodiment of the phosphoric acid fuel cell of the present invention.

FIG. 3 is a perspective view showing a basic configuration of a third embodiment of the phosphoric acid fuel cell of the present invention.

FIG. 4 is a cross-sectional view of a fuel cell stack showing a fuel gas flow path configuration in a third embodiment.

FIG. 5 is a perspective view showing a basic configuration example of a conventional phosphoric acid fuel cell.

FIG. 6 is an explanatory view schematically showing an arrangement of cooling water pipes embedded in a cooling plate and a temperature distribution of cells in a conventional basic configuration example.

FIG. 7 is a characteristic diagram showing a relationship between an exhaust gas temperature and a phosphoric acid concentration in the exhaust gas.

FIG. 8 is a cross-sectional view of a fuel cell stack showing an example of a flow path configuration of a return flow system.

[Explanation of symbols]

 Reference Signs List 1 matrix 2 fuel electrode 3 air electrode 4A, 4B porous carbon plate (fuel electrode side) 4a, 4b, 4c protrusion 5 porous carbon plate (air electrode side) 6 cooling plate 7 separator 8 cooling water inlet 9 cooling water outlet 10, 10A Fuel gas supply manifold 11, 11A Fuel gas discharge manifold 12 Air supply manifold 13 Air discharge manifold 14 Intermediate manifold 15 Intermediate manifold 16A, 16B Partition plate 17A, 17B Fuel flow path forming plate

Claims (3)

[Claims] 1. A fuel cell having a rectangular plate-like matrix containing a phosphoric acid electrolyte sandwiched between a fuel electrode having a catalyst layer bonded to a surface in contact with the matrix and an air electrode, and a fuel gas flow groove provided on an outer surface of the fuel electrode. A single cell comprising a porous carbon plate provided with a porous carbon plate having an air flow groove orthogonal to the fuel gas flow groove on the outer surface of the air electrode is disposed through a gas impermeable separator. A plurality of sheets are stacked to form a stacked block, and the stacked blocks are alternately stacked with the cooling plate to form a substantially rectangular parallelepiped fuel cell stack, and two side surfaces opposed to the extending direction of the fuel gas flow grooves. One of the fuel gas supply manifold,
A fuel gas discharge manifold is provided on the other side, an air supply manifold is provided on one of the remaining side surfaces, and an air discharge manifold is provided on the other side.The fuel gas is supplied from the fuel gas supply manifold and flows through the fuel gas flow groove. To discharge the used fuel gas from the fuel gas discharge manifold, supply air from the air supply manifold, and let the air flow through the air flow groove to discharge the used air from the air discharge manifold. In a phosphoric acid fuel cell that generates power by reaction, the end of the porous carbon plate provided with the fuel gas flow groove is:
A phosphoric acid type fuel cell, which is disposed so as to protrude into a fuel gas discharge side manifold. 2. A fuel cell having a rectangular plate-like matrix containing a phosphoric acid electrolyte sandwiched between a fuel electrode having a catalyst layer bonded to a surface in contact with the matrix and an air electrode, and a fuel gas flow groove provided on an outer surface of the fuel electrode. A plurality of single cells each having a porous carbon plate provided with an air flow groove on the outer surface of the air electrode are stacked through a gas impermeable separator to form a stacked block. Further, the stacked blocks are alternately stacked with the cooling plate to form a substantially rectangular parallelepiped fuel cell stacked body, and a pair of fuel gas manifolds is provided on two side surfaces facing the extending direction of the fuel gas flow grooves. A fuel gas supply manifold, at least one intermediate manifold and a fuel gas discharge manifold are disposed on one of the fuel gas supply manifold and the air supply manifold on one of the remaining side surfaces of the fuel cell stack,
An air discharge manifold is provided on the other side, fuel gas is supplied from the fuel gas supply manifold, and is passed through a part of the fuel gas flow groove and sent to the intermediate manifold. After flowing through the fuel gas flow groove, it is sent to the fuel gas discharge manifold to discharge the used fuel gas, air is supplied from the air supply manifold, and the air discharge manifold is flowed through the air flow groove. In a phosphoric acid type fuel cell that discharges more used air and generates power by an electrochemical reaction, the end of the porous carbon plate provided with the fuel gas flow groove,
A phosphoric acid type fuel cell characterized in that it is disposed so as to protrude into an intermediate manifold of a fuel gas manifold. 3. The phosphoric acid fuel cell according to claim 2, wherein the electrically insulating material extends in the stacking direction in contact with the end face of the porous carbon plate protruding into the intermediate manifold of the fuel gas manifold. And a flow path for fuel gas is formed between the flow path forming plate and the protruding portions of two porous carbon plates adjacent in the laminating direction. Acid type fuel cell.