JP5295554B2 - Fuel cell and fuel cell separator - Google Patents

Description

  The present invention relates to a fuel cell and a fuel cell separator.

  In a fuel cell system using a polymer electrolyte membrane having proton conductivity as an electrolyte, a fuel gas containing hydrogen (anode reaction gas) is supplied to the fuel electrode (anode electrode) and an oxidant gas containing oxygen (cathode reaction). Gas) is supplied to the oxidant electrode (cathode electrode) to generate electricity. In that case, fuel gas and oxidant gas are supplied along the gas flow path provided in the separator with respect to the layered fuel electrode, the solid polymer electrolyte membrane, and the oxidant electrode. The gas flow path communicates with the gas supply / discharge manifold and the gas return manifold, and the fuel gas and the oxidant gas are supplied from the gas supply section of the gas supply / discharge manifold through the gas return manifold and from the upstream of the gas flow path. It flows downstream and is discharged to the outside from the gas discharge portion of the gas supply / discharge manifold. The battery reaction consumes hydrogen in the fuel gas and oxygen in the oxidant gas, and the reaction product water is discharged as water vapor.

  On the other hand, the solid polymer electrolyte membrane has a characteristic that the moisture content of the membrane changes due to the equilibrium water vapor pressure, and the resistance of the electrolyte membrane changes, and in order to reduce the resistance of the electrolyte membrane and obtain sufficient power generation performance, It is necessary to add moisture to the polymer electrolyte membrane, that is, humidification. There are two types of humidification: an external humidification method in which water vapor is added to the fuel gas or oxidant gas in advance, and an internal humidification method in which water is directly added via a separator.

  This polymer electrolyte fuel cell stack is generally configured by inserting a separator for each unit cell. This separator has a cooling and heat removal function for removing heat generated by the unit battery power generation, a conductive function for electrically connecting the unit cells in series, and the separator side of one unit cell disposed via the separator. Reactive gas blocking function to prevent mixing through the fuel gas or oxidant gas flowing through the separator and the separator of the other unit cell disposed through the separator through the oxidant gas or fuel gas separator have. In addition, it has mechanical strength capable of maintaining its shape under a predetermined lamination tightening.

  These separators form a reaction gas channel for supplying fuel gas (or oxidant gas) to the unit cell reaction surface on one side, and a channel for circulating cooling water on the other side. The formed plate and the plate formed with the reaction gas channel for supplying the oxidant gas (or fuel gas) to the unit cell reaction surface only on one surface are integrated with the cooling water channel forming surface and the flat surface as the adhesive surface. Generally, it is formed.

  Moreover, although the metal system represented by patent document 1 is proposed as a material of a separator, generally the separator which has a carbonaceous or graphitic carbon material as a main component is used from a durable point. .

  A separator mainly composed of carbonaceous material or graphite is used by being fixed to a resin having a function of adhering and binding those powder particles and forming a plate. As the resin having an adhesion / binding function, a phenol resin, a thermosetting resin typified by an epoxy resin, or a thermoplastic resin typified by a polyphenylene resin (PPS) is generally used. Furthermore, a separator obtained by high-temperature treatment (carbonization treatment or graphitization treatment) of the plate is used for the purpose of improving durability and improving electrical conductivity.

  This separator mainly composed of carbonaceous or graphite is generally mixed with the above-mentioned carbonaceous or graphite powder by using a thermosetting resin as an adhesive / binder from the viewpoint of cost and reliability of physical properties. It is formed from a plate obtained by hot pressing the kneaded material. In addition, in order to satisfy the above separator function, this mixed and kneaded product is a molding aid such as 90% by weight or more of carbonaceous or graphite powder, 10% by weight or less of thermosetting resin (and curing agent), and internal release agent. What has a composition with an agent is used.

  For the above-described molded separator mainly composed of carbonaceous or graphite, a method of integrating a molded flat plate after subjecting it to predetermined machining or a method of performing direct grooving and integrating it is employed.

  In the machining method, a reaction gas passage for supplying fuel gas (or oxidant gas) to the unit cell reaction surface is formed by machining on one side of the molded flat plate, and cooling water is circulated on the other side. The flow path for making it is formed by machining. Further, a reaction gas flow path for supplying oxidant gas (or fuel gas) to the unit cell reaction surface only on one surface of another formed flat plate is formed by machining. These machining plates are formed by integrating the cooling water flow path forming surface and the flat surface as an adhesive surface.

  In addition, for the purpose of eliminating machining, a method of forming a grooved plate of a reaction gas channel and a cooling water channel using a grooved mold is also used. A grooved plate having a reaction gas channel for supplying fuel gas (or oxidant gas) to the unit cell reaction surface on one side and a channel for circulating cooling water on the other side Mold with Further, a grooved plate having a reaction gas flow path for supplying an oxidant gas (or fuel gas) to the unit cell reaction surface only on one surface is formed in one stage. These grooved molding plates are integrated with a cooling water flow path forming surface and a flat surface as an adhesive surface to form a separator.

  In recent years, from the viewpoint of rationalization of separator manufacturing and cost reduction, a method of performing direct grooving without this machining and integrating them is being taken.

  In the external humidification type polymer electrolyte fuel cell that humidifies the reaction gas with a predetermined humidity, as described in Patent Document 2, the separator material itself usually has a dense structure. Impervious to reaction gas and cooling water.

  In addition, in the fuel cell described in Patent Document 3, a porous separator having a function of humidifying a reaction gas and a function of removing condensed water in a unit cell in addition to the function of the separator has been proposed.

Regarding the porous separator, in the fuel cell described in Patent Document 4, the separator on the side in contact with at least one side of the fuel electrode and the oxidant electrode increases the porosity on the other side and decreases the porosity on the other side. Proposed.
JP 2003-193206 A JP 2004-281261 A Japanese Patent Publication No. 7-95447 JP-A-2005-142015

  However, when performing direct grooving, the composition of a molding material for functioning as a separator as described above, in particular to provide electrical and thermal conductivity characteristics, is about 90% by weight of carbonaceous or graphite powder and 10% by weight. In general, those having a composition of about 25% thermosetting resin (and a curing agent) and a molding auxiliary agent such as an internal mold release agent are used.

  This molding material has a high solid content, that is, a composition ratio of carbonaceous or graphitic powder, and as a result, the amount of resin must be low, so the flow rate of the material during hot pressing is small. . Therefore, in order to obtain a uniform density, it is important to control the input position and the input amount of the material in accordance with the shape of the molded product. If this control fails, there is a problem that a separator with non-uniform density is formed. It was. This is particularly likely to occur in a portion having a large volume per unit area of the separator, and the density of this portion is reduced, and this portion functions as a separator (especially, electrical conductivity, thermal conductivity, reactive gas and cooling water sealability and machine Mechanical strength) cannot be satisfied, and a plate unsuitable as a separator is produced.

  In addition, if too much molding material is added locally, pressure is applied to the part, resulting in defects such as non-uniform thickness, density non-uniformity, and insufficient physical properties of the insufficient part due to insufficient curing pressure. As a result, there was a problem that the function as a separator could not be satisfied.

  In order to uniformly put a material into a mold, a method of feeding a preformed plate having a material arrangement in accordance with the in-plane density distribution into the mold is also generally performed. In particular, it is difficult to insert the molding material into the mold with good reproducibility at the end of the separator. If the amount of material input is insufficient, the probability of “nest-like” defects is increased. When a fuel cell is stacked using a separator having a defect at such an end, there is a problem that power generation cannot be performed due to a problem that a reaction gas or cooling water leaks through a gap formed between the separators.

  Further, it is very difficult to make the distribution of the porosity in the direction in which the pressing pressure at the time of molding is applied as in the fuel cell described in Patent Document 4, and in addition, the water movement in the plate is difficult. Or cause a problem of battery performance degradation due to hindrance. Also, the problem of edge defects cannot be solved.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress leakage of a reaction gas or the like through a gap of a direct grooved separator used in a fuel cell, and suppress deterioration in battery performance. .

In order to achieve the above object, a fuel cell separator according to the present invention has at least one of a fuel gas flow channel and an oxidant gas flow channel, and has a carbonaceous or graphite powder as a main component. In a porous fuel cell separator manufactured using a uniform material including a thermosetting resin or a thermoplastic resin as a material, the porosity is relatively small because the separator is disposed in a part of the periphery of the separator. A high-density region having a relatively high density, and a low-density region having a relatively high porosity and a relatively low density compared to the high-density region by forming the separator other than the high -density region. , Bei example a hydrogenated fuel cell using a solid polymer electrolyte membrane having proton conductivity as an electrolyte, the water vapor in at least one of the fuel cell fuel gas and the oxidant gas flow passage is supplied to the A porous separator used for an internal humidification system having a function of forming a laminated body by laminating a plurality of unit cells, and the fuel gas flow path and the oxidant gas flow path on the outer side surface of the laminated body, respectively A separator used in a fuel cell in which a plurality of gas manifolds extending in the stacking direction to communicate with each other is disposed, and only a portion of the peripheral portion of the separator that contacts the wall of the gas manifold is in the high-density region. It is characterized by becoming .

The fuel cell according to the present invention has a fuel gas flow path and an oxidant gas flow path, and is composed of a carbonaceous or graphite powder as a main component and a thermosetting resin or a thermoplastic resin as an adhesive / binder. uniform materials have a fuel cell separator manufacturing porous with a unit cell using a solid polymer electrolyte membrane having proton conductivity is stacked body while stacking a plurality is formed as an electrolyte comprising, A fuel cell in which a plurality of gas manifolds extending in the stacking direction to communicate with each of the fuel gas channel and the oxidant gas channel are disposed outside the side surface of the stack, in only the portion in contact with the wall of the gas manifold, the density is relatively large porosity is relatively large compared to other portions, the less of the fuel gas channel and the oxidizing gas channel Meanwhile it has a function of adding water vapor to be characterized.

  ADVANTAGE OF THE INVENTION According to this invention, the leakage of the reactive gas etc. through the clearance gap of the direct grooved separator used in a fuel cell can be suppressed, and a battery performance fall can be suppressed.

  Embodiments of a fuel cell and a fuel cell separator according to the present invention will be described below with reference to the drawings. Here, the same or similar parts are denoted by common reference numerals, and redundant description is omitted.

[First Embodiment]
FIG. 1 is a plan view showing an upper surface of a first plate in the fuel cell separator according to the first embodiment of the present invention, and FIG. 2 is a bottom view showing a lower surface of the first plate in FIG. 3 is a plan view showing the upper surface of the second plate in the fuel cell separator according to the first embodiment, and FIG. 4 is a bottom view showing the lower surface of the second plate in FIG. Further, FIG. 5 is a partial sectional elevation view of the fuel cell stack according to the first embodiment of the present invention, and FIG. 6 is a plan sectional view of the fuel cell according to the first embodiment.

  As shown in FIG. 5, in the fuel cell according to this embodiment, the fuel electrode 1 and the oxidant electrode 2 are arranged across the solid polymer electrolyte membrane 3 having proton conductivity. The outer side of the fuel electrode 1 and the oxidant electrode 2 is further sandwiched by the separator 4. The separator 4 includes a first plate 13 adjacent to the oxidant electrode 2 and a second plate 14 adjacent to the fuel electrode 1. The solid polymer electrolyte membrane 3, the fuel electrode 1, the oxidant electrode 2, the first plate 13, and the second plate 14 constitute one unit cell 40, and a plurality of unit cells 40 are stacked to form a fuel cell. The laminated body 11 is comprised.

  An oxidant gas flow path 6 is formed at a position adjacent to the oxidant electrode 2 of the first plate 13, and a fuel gas flow path 5 is formed at a position adjacent to the fuel electrode 1 of the second plate 14. Further, the cooling water flow path 7 is formed at a position adjacent to the second plate of the first plate 13. Further, an end seal sheet fixing step 15 is formed on the same surface as the oxidant gas flow path 6 of the first plate 13.

  As shown in FIG. 6, six manifolds extending in the stacking direction are formed on the side surface of the fuel cell stack 11, and each manifold communicates with a specific gas flow path or cooling water flow path of each unit cell. .

  That is, the fuel gas supply manifold 8a communicates with the fuel gas flow path 5, from which fuel gas containing hydrogen is supplied. The fuel gas discharge manifold 8b is disposed on the opposite side of the fuel gas supply manifold 8a and communicates with the fuel gas flow path 5, from which fuel gas is discharged. The oxidant gas supply manifold 9a communicates with the oxidant gas flow path 6, from which oxidant gas containing oxygen is supplied. The oxidant gas discharge manifold 9b is disposed on the opposite side of the oxidant gas supply manifold 9a and communicates with the oxidant gas flow path 6, from which the oxidant gas is discharged. The cooling water supply manifold 10a communicates with the cooling water flow path 7, from which a cooling medium (cooling water) is supplied. The cooling water discharge manifold 10b is disposed on the opposite side of the cooling water supply manifold 10a and communicates with the cooling water flow path 7, from which the cooling medium is discharged.

  The battery reaction consumes hydrogen in the fuel gas and oxygen in the oxidant gas, and the reaction product water is discharged as water vapor.

  The separator 4 includes a cooling heat removal function for removing heat generated by the unit battery power generation, a conductive function for electrically connecting the unit cells in series, and a fuel gas of the unit cells adjacent to each other via the separator. It has a reactive gas blocking function to prevent mixing of oxidant gas. In addition, it has mechanical strength capable of maintaining its shape under a predetermined lamination tightening.

  The material of the separator 4 is mainly composed of a carbonaceous or graphitic carbon material, for example. The separator 4 mainly composed of carbonaceous material or graphite material may be used by fixing it with a resin having a function of adhering and binding those powder particles and forming a plate. As the resin having an adhesion / binding function, a phenol resin, a thermosetting resin typified by an epoxy resin, or a thermoplastic resin typified by a polyphenylene resin can be used. The plate may be subjected to high-temperature treatment (carbonization treatment or graphitization treatment) for the purpose of improving durability and electrical conductivity. The separator 4 mainly composed of carbonaceous or graphite is mixed and kneaded with carbonaceous or graphite powder using a thermosetting resin as an adhesive / binder from the viewpoint of cost and reliability of physical properties. The material may be formed from a hot-pressed plate.

  The separator 4 in this embodiment is a dense separator that is impervious to the reaction gas and cooling water.

  As shown in FIGS. 1, 2, and 4, the oxidant gas flow path 6 is formed on the upper surface of the first plate 13, the cooling water flow path 7 is formed on the lower surface of the first plate 13, and the second A fuel gas flow path 5 is formed on the lower surface of the plate 14. These flow paths 5, 6, 7 are formed as a number of parallel grooves formed on the surfaces of the plates 13, 14. However, illustration of each groove | channel is abbreviate | omitted in FIG.1, FIG.2, FIG.4.

  In FIG. 1 to FIG. 4, shaded portions indicate the high density regions 19 of the plates 13 and 14. The high density region 19 is located at a common position on the front and back sides of the plates 13 and 14. The high-density region 19 is a range where the stacked body 11 and the seal portions of the manifolds 8a, 8b, 9a, 9b, 10a, and 10b are in contact with each other when the batteries are stacked. is there.

The inventors manufactured a grooved mold for forming the separator 4 as a specific example of the present embodiment, and at the time of manufacturing the separator 4, the region 19 having a high density has a volume ratio of 1.2 to the proportion of the molded product. Double the amount of raw materials. Further, as a comparative example, when manufacturing a conventional separator, an amount of raw materials corresponding to the volume of the molded product was charged over the entire surface. Molding tests were performed using molding materials having the compositions shown in Table 1. The molding temperature was 170 ° C., the pressing pressure was 15 MPa, the pressing time was 5 minutes, and the post-curing treatment was performed at 200 ° C. for 6 hours.

The first plate (separator with air groove / cooling water groove) 13 and the second plate (separator with fuel groove) 14 were integrated using an adhesive to produce the separator 4. A stack 11 was manufactured by alternately stacking a plurality of integrated separators 4 and electrodes, and a manifold was attached to four side surfaces of the stack 11. Cooling water was passed through the cooling water system and pressurized to investigate the leakage of water to the reaction gas side. The results are shown in Table 2.

As shown in Table 2, in the conventional method, water leakage was confirmed from the gap between the sealing material of the manifold and the separator at 50 kPa or less. When the stack was disassembled after the leak test and the leak portion was confirmed, chipped edges and nest-like defects were found. Further, although different from the leaked portion, a crack was found in a part of the end seal sheet fixing step 15. The density of the separator was in the range of 1.85 to 1.95 g / cm ³ , and the density of the portion where leakage or cracking was observed was relatively small compared to other portions.

On the other hand, in the separator of this embodiment, no leak was observed even at a pressure of 50 kPa. When the density of the separator was confirmed after the leak test, the range in which the density was large was 1.97 to 2.00 g / cm ³ , while the other portions were in the range of 1.93 to 1.97 g / cm ³ . .

  From the above results, it can be seen that the direct grooved separator according to the present embodiment has an excellent effect as compared with the conventional direct grooved separator.

[Second Embodiment]
The separator according to the second embodiment of the present invention is a porous separator having a function of humidifying reaction gas and a function of removing condensed product water in the unit cell.

  1 to 6 according to the first embodiment are common to the second embodiment. However, in the present embodiment, the high-density region 19 in FIGS. 1 to 4 is realized as a region having a low porosity.

  As a specific example of the present embodiment, the inventors manufactured a grooved mold for molding a separator. When the separator 4 was manufactured, the high density region 19 having a low porosity has a volume ratio of 1 for the molded product. .1 times the amount of raw material was added. Further, as a comparative example, when manufacturing a conventional separator, an amount of raw materials corresponding to the volume of the molded product was charged over the entire surface. Molding tests were performed using molding materials having the compositions shown in Table 1. The molding temperature was 170 ° C., the pressing pressure was 3 MPa, the pressing time was 10 minutes, and the post-curing treatment was performed at 200 ° C. for 10 hours.

A first plate (separator with air groove / cooling water groove) 13 and a second plate (separator with fuel groove) 14 were produced. These plates were submerged in water, and the pressure reduction was repeated 5 times. The plate base material was completely impregnated with water, and a foaming pressure test was performed. Pressurization was performed using nitrogen from the cooling water side. The results are shown in Table 3.

  As shown in Table 3, in the conventional system, the wet seal was broken and bubbles were observed at a bubble-free pressure of 30 kPa or less in the portion without the gas flow passage groove of the anode, but in this embodiment, a bubble-jet pressure of 50 kPa or more was observed. It was shown to have.

Further, a stack 11 was manufactured by alternately stacking several sheets of integrated separators 4 and electrodes, and a manifold was attached to four side surfaces of the stack 4. Cooling water was passed through the cooling water system and pressurized to investigate the leakage of water to the reaction gas side. The results are shown in Table 4.

  As shown in Table 4, in the conventional method, water leakage was confirmed from the gap between the sealing material of the manifold and the separator at 50 kPa or less. When the stack was disassembled after the leak test and the leak portion was confirmed, chipped edges and nest-like defects were found. The porosity of the separator was in the range of 20 to 35%, and the porosity in particular where leaks were observed or cracked was relatively large compared to other locations. On the other hand, in the separator of this embodiment, no leak was observed even at a pressure of 50 kPa. When the porosity of the separator was confirmed after the leak test, the small range of the porosity was 15 to 20%, while the other portions were in the range of 20 to 25%.

  From the above results, it can be seen that the direct grooved separator according to the present embodiment has an excellent effect as compared with the conventional direct grooved separator.

  Since an excessive pressure is applied at the time of molding in a region with a low porosity, it affects the molding pressure in a region with a high porosity, and therefore, control of the amount of material input and the molding pressure is important.

  In the present embodiment, a method of increasing the input amount of raw materials is adopted as a means for reducing the porosity, but it goes without saying that the method is not limited to this method as long as the porosity can be reduced. For example, the same effect can be obtained by a method in which a small piece having a low porosity is manufactured in advance, and the small piece is placed at a necessary position at the time of molding and then molded together with raw materials. Further, the separator in the present embodiment is produced by hot-pressing a material containing carbonaceous or graphite powder as a main component and containing a thermosetting resin or a thermoplastic resin as an adhesive / binder, In addition, a grooved mold for forming a separator groove is used as a molding mold, but it goes without saying that the same effect can be obtained for a separator formed by injection molding instead of hot / pressure molding. .

[Third Embodiment]
FIG. 7 is a plan view showing the upper surface of the first plate in the fuel cell separator according to the third embodiment of the present invention, and FIG. 8 is a bottom view showing the lower surface of the first plate in FIG. FIG. 9 is a plan view showing the top surface of the second plate in the fuel cell separator according to the third embodiment, and FIG. 10 is a bottom view showing the bottom surface of the second plate in FIG. 5 and 6 showing the fuel cell according to the first embodiment of the present invention are common to the fuel cell according to the third embodiment.

  The third embodiment is a modification of the second embodiment in which the high-density region 19 having a low porosity is minimized.

  7 to 10 show the first plate 13 and the second plate 14, and the dotted line indicates the position where each manifold for supplying gas to each unit cell 40 is mounted after a plurality of separators 4 are stacked. It shows with. In this embodiment, the high-density region 19 having a small porosity is formed only in the position where it contacts the seal surface that contacts the walls of the manifolds 8a, 8b, 9a, 9b, 10a, and 10b. By arranging the high density region 19 in this way, the high density region 19 can be minimized. In addition, leaks due to separator defects can be prevented.

[Other Embodiments]
Each embodiment described above is merely an example, and the present invention is not limited thereto.

  For example, in the above embodiment, the high density region is provided in a part of the periphery of the separator, but the same effect can be obtained even if the entire periphery is made a high density region.

  In the first embodiment, a method of increasing the input amount of raw materials is adopted as a means for increasing the density. However, it is needless to say that the method is not limited to this method as long as the density can be increased. For example, a similar effect can be obtained by manufacturing a small piece of high density in advance and placing the small piece in a necessary place at the time of molding together with the raw material.

  In the third embodiment, as a modification of the second embodiment, the high-density region 19 having a small porosity is limited to a specific position, but as a modification of the first embodiment, the reaction gas and In the dense separator that is impervious to the cooling water, the high-density region 19 may be disposed only in the same specific position.

  In the above description, for convenience of description, the expressions “upper” and “lower” are used. However, the fuel cell stack 11 and the separator may be arranged in any orientation, and may be upside down.

  Furthermore, in the above embodiment, the oxidant gas flow path 6 and the cooling water flow path 7 are formed on the front and back of the first plate 13, and the fuel gas flow path 5 is formed on the second plate 14. As an example, the fuel gas passage and the cooling water passage may be formed on the front and back of one plate, and only the oxidant gas passage may be formed on the other plate.

It is a top view which shows the upper surface of the 1st plate in the separator for fuel cells which concerns on the 1st Embodiment of this invention. It is a bottom view which shows the lower surface of the 1st plate of FIG. It is a top view which shows the upper surface of the 2nd plate in the separator for fuel cells which concerns on the 1st Embodiment of this invention. It is a bottom view which shows the lower surface of the 2nd plate of FIG. It is a partial elevation sectional view of a fuel cell layered product concerning a 1st embodiment of the present invention. 1 is a cross-sectional plan view of a fuel cell according to a first embodiment of the present invention. It is a top view which shows the upper surface of the 1st plate in the separator for fuel cells which concerns on the 3rd Embodiment of this invention. It is a bottom view which shows the lower surface of the 1st plate of FIG. It is a top view which shows the upper surface of the 2nd plate in the separator for fuel cells which concerns on the 3rd Embodiment of this invention. It is a bottom view which shows the lower surface of the 2nd plate of FIG.

Explanation of symbols

1: Fuel electrode (anode electrode)
2: Oxidant electrode (cathode electrode)
3: Solid polymer electrolyte membrane 4: Separator 5: Fuel gas channel 6: Oxidant gas channel 7: Coolant water channel 8a: Fuel gas supply manifold 8b: Fuel gas discharge manifold 9a: Oxidant gas supply manifold 9b: Oxidation Agent gas discharge manifold 10a: Cooling water supply manifold 10b: Cooling water discharge manifold 11: Fuel cell stack (stack)
13: First plate 14: Second plate 15: End seal sheet fixing step 19: High density region 40: Unit cell

Claims (5)

At least one of a fuel gas flow path and an oxidant gas flow path is formed, and a uniform material including a thermosetting resin or a thermoplastic resin as a bonding / binding material mainly composed of carbonaceous or graphite powder is used. In the produced porous fuel cell separator,
A high density region that is disposed in a part of the periphery of the separator and has a relatively small porosity and a relatively large density, and the separator other than the high density region is formed in the high density region. compared Bei example and density is relatively small low-density region porosity is relatively large, the, the
In a fuel cell using a solid polymer electrolyte membrane having proton conductivity as an electrolyte, used for an internal humidification system having a function of adding water vapor to at least one of a fuel gas and an oxidant gas flow path supplied to the fuel cell A porous separator,
A plurality of unit cells are stacked to form a stacked body, and a plurality of gas manifolds extending in the stacking direction are disposed outside the side surfaces of the stacked body so as to communicate with the fuel gas flow path and the oxidant gas flow path, respectively. A separator used in a fuel cell,
Only the part which touches the wall of the said gas manifold among the peripheral parts of the said separator is the said high-density area | region, The separator for fuel cells characterized by the above-mentioned . The fuel cell separator according to claim 1, further comprising a cooling water flow path . A separator used in a fuel cell in which a plurality of unit cells are stacked to form a stacked body, and a cooling water manifold extending in the stacking direction to communicate with the cooling water flow path is disposed outside the side surface of the stacked body. And
3. The fuel cell separator according to claim 2, wherein a portion of the peripheral portion of the separator that is in contact with a wall of the cooling water manifold is a high-density region in which the density is relatively high . A fuel gas channel and an oxidant gas channel are formed and manufactured using a uniform material containing a carbonaceous or graphite powder as the main component and a thermosetting resin or thermoplastic resin as an adhesive / binder. A plurality of unit cells having a porous separator for a fuel cell and using a solid polymer electrolyte membrane having proton conductivity as an electrolyte are laminated to form a laminate, and the fuel is disposed outside the side surface of the laminate. A fuel cell in which a plurality of gas manifolds extending in the stacking direction to communicate with the gas flow path and the oxidant gas flow path are arranged,
  Of the peripheral part of the separator, only the part in contact with the wall of the gas manifold has a relatively large porosity and a relatively large density compared to other parts,
  Having a function of adding water vapor to at least one of the fuel gas channel and the oxidant gas channel;
  A fuel cell. A cooling water flow path is further formed in the separator;
  A plurality of cooling water manifolds extending in the laminating direction to communicate with the cooling water flow path are disposed outside the side surface of the laminated body,
  The density of the part in contact with the wall of the cooling water manifold in the peripheral part of the separator is relatively larger than other parts,
  The fuel cell according to claim 4.

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