JP5175450B2 - Fuel cell - Google Patents

Description

The present invention relates to a fuel cell comprising a reaction gas manifold for circulating the reaction gas in the flow path of the cell main body, in particular, it relates to fuel cells which has been subjected to improvement in the material constituting the reaction gas manifolds.

  A fuel cell is a power generator that supplies a fuel gas, such as hydrogen, and an oxidant gas, such as air, to the cell body to cause an electrochemical reaction, converting the chemical energy of the fuel directly into electrical energy and taking it out. Device. This fuel cell has been evaluated as a power generation device that has high power generation efficiency and is excellent in environmental performance with less pollutant emission and noise.

  An example of such a fuel cell using a solid polymer membrane will be described with reference to FIGS. That is, as shown in FIG. 6, the fuel cell main body has a laminated body 11 in which a plurality of unit cells 1 are laminated, and a current collecting plate 2 and a fastening plate 3 are arranged at both ends of the laminated body 11. And it is comprised by fastening with the stud 4 and a nut, and a disc spring. Each cell 1 has a fuel electrode and an oxidant electrode coated with a catalyst at both ends of the solid polymer membrane, and further, a fuel electrode channel plate having a fuel electrode channel at both ends and an oxidant electrode flow. An oxidant electrode flow path plate having a path is provided.

  As shown in FIG. 7, which is a cross-sectional view of the laminate 11, there are a fuel electrode inlet manifold 6, a fuel electrode outlet manifold 7, an oxidant electrode inlet manifold 8, and an oxidant electrode outlet manifold 9 around the fuel cell body. Is arranged. The fuel gas enters the fuel electrode inlet manifold 6, passes through the fuel electrode flow channel 10 of the fuel electrode flow channel plate 5, and is discharged from the fuel electrode outlet manifold 7 to the outside of the fuel cell. Similarly, the oxidant gas enters the oxidant electrode inlet manifold 8, passes through the oxidant electrode channel of the oxidant electrode channel plate (not shown), and is discharged from the oxidant electrode outlet manifold 9 to the outside of the fuel cell.

  By the way, these externally attached fuel electrode inlet / outlet and oxidant electrode inlet / outlet manifolds (hereinafter referred to as reaction gas manifolds) 6 to 9 are generally attached to the stacked surface of the stacked body 11. The purpose is to supply the reaction gas to the cell 1 and to receive the exhaust gas from the cell 1 and send it to a predetermined next process. In addition, for the purpose of ensuring safety and preventing the battery efficiency from decreasing, it also has a function of preventing leakage of reaction gas to the outside of the battery body.

  In particular, in order to prevent leakage of the reaction gas to the outside of the battery body, the seal end surface 12 of the reaction gas manifold is attached to the stacked surface of the stacked body 11 via the seal material 13. And this reaction gas manifold 6-9 needs the structure which can be fixed in the state which pressed the sealing material 13 with the force more than predetermined | prescribed so that reaction gas sealing can be performed reliably.

  In the past, in order to satisfy these functions, a metal having high mechanical strength was used for the reaction gas manifold, and its production was performed by machining a thick plate or by welding a metal plate. It was common. In addition, as shown in Patent Document 1, a reactive gas manifold having a function as a cooling water manifold is also proposed in which a corrosion prevention layer is provided on the inner surface of the manifold.

Further, as a substitute material for a metal material, a machined glass woven fabric resin laminate having high strength and high corrosion resistance is also used as a reaction gas manifold. Patent Document 1 also proposes a composite resin reaction gas manifold in which a portion that is not in direct contact with the fuel gas and the oxidant gas is covered with a metal member.
JP 2001-167789 A

  However, since the conventional reactive gas manifold is manufactured by machining (cutting out, welding, etc.) a metal material, the mechanical strength is sufficient, but the manufacturing cost is increased. In addition, when a woven fabric reinforced laminated resin material having high mechanical strength is used, it is difficult to manufacture a final shape as illustrated in FIG. There is a need. For this reason, there exists a problem that the manufacturing cost becomes high like the machining of a metal material.

  Further, in the resin-made reaction gas manifold as shown in Patent Document 1, machining of the reaction gas manifold itself can be omitted, but a metal reinforcing material subjected to machining is indispensable, and as a result, the manufacturing cost is reduced. The problem remains that does not decrease.

The present invention has been proposed in order to solve the above-described problems of the prior art, and the object of the present invention is that the reaction gas manifold can be manufactured at a low cost without the need for processing. and to provide a mechanical strength fuel cells which is obtained such.

In order to achieve the above object, the present invention provides an electrolyte membrane, a fuel electrode and an oxidant electrode respectively disposed on both surfaces of the electrolyte membrane, and a flow path for supplying a reaction gas to the fuel electrode and the oxidant electrode. In a fuel cell having a battery main body including at least one cell including a flow path plate that constitutes, a plurality of reaction gas manifolds for circulating a reaction gas through the flow path are provided around the battery main body. The plurality of reactive gas manifolds are formed of a resin in which an opening portion that opens toward the battery body and a plate-like fixing portion that protrudes outward from an end portion of the opening portion are formed. The fixed part includes a bolt hole for fastening and fixing penetrating in a direction perpendicular to the fixed part, and a reinforcing part, and the reinforcing part is the battery of the fixed part. Body The opposite face, the integrally formed on the outer wall of the reaction gas manifold, characterized in that it is a plate-like member extending in the vertical direction with respect to the fixed part.

  In the present invention as described above, since the reaction gas manifold is a molded product that can be manufactured in a lump with a resin, it can be manufactured at low cost without satisfying processing, and satisfies the required mechanical strength. Is possible.

According to the present invention as described above, the reaction gas manifold, takes the hassle of working, it is possible to manufacture at low cost, it is possible to provide a fuel cells that sufficient mechanical strength can be obtained.

  The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be specifically described with reference to the drawings. Note that the description of the same configuration and operation as those of the prior art shown in FIGS. 6 and 7 is omitted.

[First Embodiment: FIGS. 1 and 2]
[Constitution]
A first embodiment of the present invention will be described. The basic configuration of this embodiment is the same as that of the prior art shown in FIGS. 6 and 7, and a plurality of manifolds (fuel electrode inlet manifolds 6, 6) around the stack 11 (see FIG. 7) of the cell 1. A fuel electrode outlet manifold 7, an oxidant electrode inlet manifold 8, and an oxidant electrode outlet manifold 9) are arranged via a seal material 13.

These reaction gas manifolds 6 to 9 are manufactured by injection molding using an epoxy resin as shown in FIGS. 1 and 2. At this time, the tightening bolt hole 14 and the reinforcing portion 18 are also molded together. Here, an example of the material used for the injection molding is shown in Table 1.

  The reaction gas manifolds 6 to 9 manufactured as described above are fixed to both the fastening plates 3 fastening the laminate 11 by bolt fastening via the fastening bolt holes 14. This fixing force is transmitted to the seal end face 12 and pressurizes / compresses the seal material 13 so that the seal function is exhibited. The thickness of the seal end face 12 may be, for example, a width of 6 mm in order to prevent occurrence of deviation from the seal material 13 due to deformation at the time of tightening or dropout of the seal material 13, but is not limited thereto. .

[Action]
The sealing function in this embodiment as described above will be described. First, one of the most important functions of the reaction gas manifolds 6 to 9 is to prevent leakage of reaction gas to the outside (or cooling water if it has a cooling water manifold function) to the outside. Consider. That is, if the force (pressing force) required for the sealing material 13 can be applied to the sealing material 13 interposed between the sealing end surface 12 and the laminated surface of the laminated body 11, the prevention of reaction gas leakage can be achieved. .

  In order to prevent leakage of the reaction gas, it is not always necessary to increase the strength of the reaction gas manifolds 6 to 9. The seal end surface 12 is structurally strong enough and the reaction gas manifolds 6 to 9 are attached. -In tightening, it means that the tightening force can be applied to the seal end surface 12. Therefore, in the present embodiment, the above structure is realized by manufacturing the reaction gas manifolds 6 to 9 themselves by injection molding using an epoxy resin.

  Actually, a test for confirming the sealing function of the reaction gas manifold of the present embodiment was conducted. In this experiment, first, a pair of reaction gas manifolds A and B of this embodiment are arranged on both sides of an aluminum plate having a thickness of 5 mm, and a silicon rubber sheet (hardness 40, 3 mm thickness) cut into a predetermined shape as a sealing material is used. Clamping to cause 25% deformation was performed. The tightening was performed by performing bolt tightening through the respective tightening bolt holes in the pair of reaction gas manifolds A and B.

Then, after applying an internal pressure of 0.15 kPa to both of the reaction gas manifolds A and B, sealing was performed, and a sealing property evaluation test was performed in which a decrease rate of the internal pressure was measured. The results of this test are shown in Table 2 below.

  From the above, it was confirmed that even after 30 minutes had elapsed, the internal pressure did not decrease and the sealing function was sufficient. In addition, there was no displacement or omission of the sealing material. At this time, when the external dimensions of the seal end faces of the reaction gas manifolds A and B were measured, it was confirmed that the deformation was within 0.1 mm and sufficient strength compared to before tightening. did it.

[effect]
As is clear from the above, according to the present embodiment, the reaction gas manifolds 6 to 9 can be sufficiently molded for a polymer electrolyte fuel cell by batch molding by injection molding of epoxy resin.

  Further, the manufacturing of the reaction gas manifolds 6 to 9 eliminates the need for conventional machining and is completed by a single resin injection molding including the tightening bolt hole 14 and the reinforcing portion 18, so that it is inexpensive and reliable. Reaction gas manifolds 6 to 9 and a polymer electrolyte fuel cell using the same can be constructed.

[Second Embodiment: FIG. 3, FIG. 4, FIG. 5]
[Constitution]
A second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, reaction gas manifolds 6 to 9 are basically manufactured in the same manner as in the first embodiment. However, in this embodiment, inclined surfaces 19 as shown in FIG. 3 are provided on both sides of the reaction gas manifolds 6 to 9. In addition, as shown in FIG. 4, the fastening bolt hole 14 and the reinforcement part 18 are also collectively formed.

  Then, the reaction gas manifolds 6 to 9 are arranged so as to surround the laminated body 11, and the adjacent gas manifolds 6 to 9 are bolted to each other through the fastening bolt holes 14 by using the inclined surfaces 19. It is configured to fasten and tighten. Thereby, the tightening force due to the bolt fastening is transmitted to the seal end face 12 and pressurizes / compresses the seal material 13, so that the seal function is exhibited. The thickness of the seal end face 12 may be, for example, a width of 6 mm in order to prevent occurrence of deviation from the seal material 13 due to deformation at the time of tightening or dropout of the seal material 13, but is not limited thereto. .

[Action]
A test for confirming the sealing function of the reaction gas manifold in the present embodiment as described above was conducted. FIG. 5 is a side view showing this test mode. That is, a pair of gas manifolds A and B of this embodiment are arranged on both surfaces of a 5 mm thick aluminum plate 15, and a silicon rubber sheet (hardness 40, 3 mm thickness) cut into a predetermined shape is interposed as a sealing material 13. , Tightening to produce a deformation of 25%.

Tightening was performed by fastening the fastening bolt holes 14 in the pair of reaction gas manifolds A and B using the bolt fastening portion 17 via the spacer 16. Then, after applying an internal pressure of 0.15 kPa to both of the reaction gas manifolds A and B, sealing was performed, and a sealing property evaluation test was performed in which a decrease rate of the internal pressure was measured. The results of this test are shown in Table 3 below.

  From the above, it was confirmed that even after 30 minutes had elapsed, the internal pressure did not decrease and the sealing function was sufficient. In addition, neither the displacement nor the dropping of the sealing material 13 was observed. At this time, when the outer dimensions of the seal gas end faces 12 of the reaction gas manifolds A and B were measured, they were accommodated by deformation within 0.1 mm as compared with those before tightening, and had sufficient strength. It could be confirmed.

[effect]
As is apparent from the above, according to the present embodiment, a solid polymer fuel cell can be constructed that has sufficient strength and is inexpensive and reliable, as in the first embodiment. Furthermore, in this embodiment, since the reaction gas manifolds 6 to 9 can be fastened to each other around the laminate 11 by bolting, a special structure on the fuel cell main body side becomes unnecessary, and maintenance can be performed. Removal and replacement are easy.

[Other Embodiments]
The present invention is not limited to the embodiment as described above. For example, in the above embodiment, the tightening portions of the reaction gas manifolds 6 to 9 are all installed on the side surface of the seal end surface 12, but the structure capable of sufficiently transmitting the tightening force to the seal end surface 12. If it is, it is not limited to said structure.

  Moreover, in said embodiment, although the epoxy resin was shown as a representative example as resin for shaping | molding of the reaction gas manifolds 6-9, it is not limited to this. For example, the present invention can be realized by any of phenolic resins that are thermosetting resins, polycarbonate resins that are thermoplastic resins, polyimide resins, polyphenylene sulfide resins, and polyether ether ketone resins. If possible, a resin having sufficient mechanical strength and capable of being maintained at a temperature of about 90 ° C., which is the operating temperature of the polymer electrolyte fuel cell, is desirable.

  In the above embodiment, the case where the reaction gas manifold is formed by injection molding has been described. However, the present invention is not limited to this. For example, the reaction gas manifold may be formed using hot pressing. It is not necessary that all the reaction gas manifolds are resin molded products, and only a part of them may be used.

Furthermore, in the above embodiment, the case where silica (SiO ₂ ) beads are used as the resin filler at the time of molding has been described. However, the filling for the purpose of improving the flow at the time of molding a molded product or improving the strength of the molded product. The material is not limited to silica beads. For example, the same effect can be obtained with silica fiber, carbon powder, carbon fiber, titanium oxide (TiO ₂ ) powder, and the like. The present invention is not limited to a polymer electrolyte fuel cell, and can be widely applied to fuel cells that require a similar manifold.

1 is a vertical sectional view of a reaction gas manifold according to a first embodiment of the present invention. FIG. 2 is a plan view of the reaction gas manifold of FIG. 1. The vertical sectional view of the reaction gas manifold in the 2nd embodiment of the present invention. FIG. 4 is a plan view of the reaction gas manifold of FIG. 3. The side view which shows the aspect of the seal function test in embodiment of FIG. The vertical sectional view showing an example of a general fuel cell main part. FIG. 7 is a vertical sectional view showing a manifold constituting the fuel cell of FIG. 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cell 2 ... Current collecting plate 3 ... Fastening plate 5 ... Fuel electrode flow path plate 6-9 ... Reaction gas manifold 10 ... Fuel electrode flow path 11 ... Laminated body 12 ... Seal end surface 13 ... Sealing material 14 ... Fastening bolt Hole 15 ... Aluminum plate 16 ... Spacer 17 ... Bolt fastening part 18 ... Reinforcement part 19 ... Inclined surface

Claims (1)

A cell comprising an electrolyte membrane, a fuel electrode and an oxidant electrode respectively disposed on both surfaces of the electrolyte membrane, and a flow path plate constituting a flow path for supplying a reaction gas to the fuel electrode and the oxidant electrode, In a fuel cell having a battery body including at least one battery,
Around the battery body, a plurality of reaction gas manifolds for allowing reaction gas to flow through the flow path are provided,
Each of the plurality of reaction gas manifolds is a resin molded product in which an opening portion that opens toward the battery body and a plate-like fixing portion that projects outward from an end portion of the opening portion are formed. Yes,
The fixing portion includes a bolt hole for fastening and fixing that penetrates in a direction perpendicular to the fixing portion by the batch molding, and a reinforcing portion.
The reinforcing portion is a plate-like member that is formed integrally with a surface of the fixing portion opposite to the battery body and an outer wall of the reaction gas manifold and extends in a direction perpendicular to the fixing portion. A fuel cell.

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