JP2006032007A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the complication of the distribution structure by three fluids and enhance the output density of a fuel cell by thinning the stacking dimension. <P>SOLUTION: Cooling fins 7, 9 are integrally installed in a outer portion than a power generation region having a gas passage (an air passage 15) of a separator 1. Outer covers 27, 29 are installed so as to cover the cooling fins 7, 9 respectively, and cooling water is supplied to a cooling water supply space on the inside of the outer covers 27, 29. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell in which an anode side electrode is disposed on one side of an electrolyte membrane, and a cathode side electrode is disposed on the other side, and the outside is sandwiched between a pair of separators.

  A fuel cell is a device that converts the chemical energy of fuel directly into electrical energy by electrochemically reacting a fuel gas such as a hydrogen-containing gas that is a reactive gas with an oxidant gas such as air. It has excellent characteristics such as high energy efficiency compared to other energy engines and no generation of exhaust gas because there is no need to use fossil fuels that have a problem of resource depletion.

  Such a fuel cell supplies hydrogen gas as a fuel gas between the anode side electrode and one separator, supplies air as an oxidant gas between the cathode side electrode and the other separator, and Cooling water is supplied to the side of the separator opposite to the electrode.

Therefore, this fuel cell supplies three fluids of hydrogen gas, air, and cooling water to a so-called power generation area inside the fuel cell (see, for example, Patent Document 1 below).
Japanese Patent Laid-Open No. 9-17437

  In the conventional fuel cell, as described above, in the power generation region inside the fuel cell, the hydrogen gas, the air, and the cooling water are respectively supplied to the electrolyte membrane having electrodes on both sides and the separator in different stacking directions. Since the three fluids are supplied separately, the three-fluid distribution structure becomes complicated, and the thickness of the laminated layer also increases, resulting in a problem that the power density of the fuel cell decreases.

  Accordingly, an object of the present invention is to prevent the distribution structure from being complicated by the three fluids and to reduce the stack thickness to improve the output density as a fuel cell.

  The present invention provides a fuel cell in which an anode side electrode is disposed on one side of an electrolyte membrane, a cathode side electrode is disposed on the other side, and the outside is sandwiched between a pair of separators. The main feature is that the separator is provided with cooling fins protruding outward from the region.

  According to the present invention, since the separator is provided with the cooling fins protruding outward from the power generation region provided with the electrodes, it is not necessary to supply the cooling medium to the power generation region, and only two fluids of fuel gas and oxidant gas are provided. The fluid distribution structure is simplified as compared with the case where three fluids are supplied to the power generation region, the stack thickness is reduced, and the output density of the fuel cell is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing the internal structure of a fuel cell according to an embodiment of the present invention. In FIG. 1, the air flow path surface of the separator 1 is visible on the front side of the drawing. 2 (a) is an enlarged front view of the vicinity of the left end of the separator 1 in FIG. 1. FIG. 2 (b) shows the separator 1 and electrodes on both sides (an anode side electrode on one side and the other side). 2 corresponds to the view seen from the top of FIG. 2 (a), and FIG. 2 (c) shows the state of the same laminated state shown in FIG. It corresponds to the figure seen from the right side of (a).

  In FIG. 1, separators 1 and solid polymer electrolyte membranes 3 are alternately laminated in the direction of arrow A, and both ends thereof are sandwiched and fixed by end plates (not shown), thereby constituting a fuel cell stack in which a large number of unit cells are laminated. .

  The separator 1 is a metal base material coated with a corrosion-resistant film such as gold, a stainless alloy, a titanium alloy, a mixture of resin and carbon, or a combination thereof. As shown in FIG. A power generation region 5 having a rectangular air flow path surface, cooling fins 7 and 9 on both upper and lower sides of the power generation region 5 in FIG. 3, and manifold portions 11 and 13 on both left and right sides of the power generation region 5, respectively. I have.

  As shown in FIG. 2C, the separator 1 is formed by pressing a metal plate made of a stainless alloy or the like into a concavo-convex shape with respect to the power generation region 5 as shown in FIG. 2C. The concave portion on the other side is referred to as an air flow path 15, and the concave portion on the other right side is referred to as a hydrogen flow path 17.

  In the vicinity of the power generation region 5 of the cooling fins 7 and 9 in the separator 1, through holes 7 a and 9 a are formed along the power generation region 5.

  One manifold portion 11 in the separator 1 includes an air inlet manifold 11a penetrating in the stacking direction on the upper side in FIG. 3 and a hydrogen outlet manifold 11b penetrating in the stacking direction on the lower side in FIG. Prepare each. The other manifold portion 13 includes a hydrogen inlet manifold 13a that penetrates in the stacking direction on the upper side in FIG. 3 and an air outlet manifold 13b that penetrates in the stacking direction on the lower side in FIG. Prepare.

  Then, on the front side of the sheet of FIG. 3 of this separator 1, the periphery of the entire rectangular portion that is long in the left-right direction in FIG. 3 including the power generation region 5 and the manifold portions 11, 13, the hydrogen outlet manifold 11 b and the hydrogen inlet manifold. Around each of 13a, the resin mold part 19 which functions as a gas seal material between laminated members is integrally molded by the metal plate.

  As a result, an air inlet guide channel 21 is formed between the air inlet manifold 11 a and the air channel 15, and both are connected between the air channel 15 and the air outlet manifold 13 b. An air outlet guide channel 23 is formed.

  Similarly, on the back side of the sheet of FIG. 3 of the separator 1, the periphery of the entire rectangular portion that is long in the left-right direction in FIG. 3 including the power generation region 5 and the manifold portions 11, 13, the air inlet manifold 11 a and the air outlet. Around each of the manifolds 13b, a resin mold portion 25 (see FIGS. 2B and 2C) that functions as a gas seal material between the laminated members is integrally formed on a metal plate.

  As a result, a hydrogen inlet guide channel (not shown) that connects both of them is formed between the hydrogen inlet manifold 13a and the hydrogen channel 17, and both of these are connected between the hydrogen channel 17 and the hydrogen outlet manifold 11b. A hydrogen outlet guide channel (not shown) to be connected is formed.

  Then, as shown in FIG. 1, upper and lower outer covers 27 and 29 are provided so as to cover the periphery of the upper and lower cooling fins 7 and 9, respectively. In the outer covers 27 and 29, the left and right end portions 27 a and 29 a in FIG. 1 are joined and fixed to the side surfaces of the manifold portions 11 and 13 of the separator 1 and the solid polymer electrolyte membrane 3. Cooling water supply spaces 31 and 33 for supplying cooling water as a cooling medium are formed between the three sides excluding the side.

  As shown in FIG. 4, the cooling water is supplied to the cooling water supply spaces 31 and 33 by a booster pump 35 provided on one side of the fuel cell stack in the stacking direction (left and right direction in FIG. 4). The booster pump 35 and the cooling water supply spaces 31 and 33 are connected by a cooling water supply pipe 37, and the temperature of the cooling water is adjusted by a temperature adjusting device 39 provided in the middle of the cooling water supply pipe 37.

  Further, on the other side in the stacking direction of the fuel cell stack, a cooling water discharge pipe 41 is connected to the cooling water supply spaces 31 and 33, and a back pressure valve 43 is installed in the middle of the cooling water discharge pipe 41. The back pressure valve 43 and the pressure increasing pump 35 control the pressure Pout applied to the cooling water.

  Note that both ends in the left-right direction in FIG. 4 of the outer covers 27 and 29 are open, and the openings are closed by end plates 45 and 47, and the through holes 45a and 47a formed in the end plates 45 and 47, respectively. The cooling water supply pipe 37 and the cooling water discharge pipe 41 are connected to each other.

  The pressure Pout applied to the cooling water is set to be equal to or higher than the gas pressure Pin (hydrogen gas pressure and air gas pressure) inside the fuel cell, as shown in FIG.

  The fuel cell described above supplies hydrogen as a fuel gas to the hydrogen flow path 17 and supplies air as an oxidant gas to the air flow path 15, which are arranged corresponding to the hydrogen flow path 17 and the air flow path 15. Power is generated by reacting in the power generation region 5 provided with the electrodes. At this time, the cooling water is supplied to the cooling water supply spaces 31 and 33 accommodating the cooling fins 7 and 9 protruding outward from the power generation region 5 by the pressure-intensifying pump 35 in a state in which the temperature and pressure are controlled. .

  The cooling water that has flowed into the cooling water supply spaces 31 and 33 cools the cooling fins 7 and 9 and suppresses a temperature rise due to heat generation in the power generation region 5. Since the cooling water also enters the through holes 7a and 9a of the cooling fins 7 and 9, the cooling effect is further enhanced.

  Thus, according to the fuel cell of the present embodiment, it is not necessary to supply cooling water to the power generation region 5, and only two fluids, hydrogen gas and air, need to be supplied to the power generation region 5. The distribution structure is simplified as compared with the case where three fluids including cooling water are supplied to the power generation region 5, the stack stack thickness is also reduced, and the output density as a fuel cell is improved.

  Moreover, since the cooling fins 7 and 9 are provided corresponding to the long sides of the power generation region 5 having a rectangular shape, compared to the case where the cooling fins are provided corresponding to the short sides of the power generation region 5, When the areas of the cooling fins are made equal, the average distance from the power generation region 5 can be shortened, and the cooling efficiency is improved.

  Further, as shown in FIG. 5, by setting the pressure Pout applied to the cooling water to be equal to or higher than the gas pressure Pin inside the fuel cell, the pressure is applied to the resin mold parts 19 and 25 having a sealing function from the outside. Therefore, the leakage of hydrogen gas and air inside the fuel cell can be prevented and the sealing performance can be improved.

  The external covers 27 and 29 may be eliminated and the cooling fins 7 and 9 may be directly cooled by air. Further, instead of the resin mold parts 19 and 25, a sealing material may be provided separately.

  According to the present invention, since the cooling fin is integrated with the separator, the cooling fin can be manufactured at the same time when the separator is manufactured, and the manufacturing cost can be reduced as compared with the case of separately manufacturing the cooling fin, The number of parts is reduced.

  Since the power generation area is rectangular and the cooling fins are provided in the parts corresponding to the long side portions of the rectangular shape, compared to the case where the cooling fins are provided in the parts corresponding to the short side parts, When the areas are equal, the average distance from the power generation region can be shortened, and the cooling efficiency is improved.

  Since an external cover that covers the periphery of the cooling fin is provided and a cooling medium is supplied into the external cover, the cooling fin can be efficiently cooled.

  Since the pressure of the cooling medium supplied into the external cover is set to be equal to or higher than the gas pressure inside the fuel cell, gas leakage inside the fuel cell can be prevented and the sealing performance can be improved.

It is a perspective view which shows the internal structure of the fuel cell concerning one Embodiment of this invention. (A) is a front view in which the vicinity of the left end of the separator of FIG. 1 is enlarged. (B) is a diagram in which separators and solid polymer electrolyte membranes having electrodes on both sides are alternately laminated. FIG. 3C is a stacking state diagram corresponding to the view seen from the top, and FIG. 2C is a stacking state diagram corresponding to the view seen from the right side of FIG. It is a front view of the whole separator in the fuel cell of FIG. It is a whole lineblock diagram showing the cooling water supply system to a fuel cell. It is sectional drawing to which the B section of FIG. 4 was expanded.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Separator 3 Solid polymer electrolyte membrane 5 Electric power generation area 7,9 Cooling fins 27,29 External cover Pout Pressure of the cooling medium supplied in an external cover Pin Gas pressure inside a fuel cell

Claims (5)

  In a fuel cell in which an anode side electrode is disposed on one side of the electrolyte membrane and a cathode side electrode is disposed on the other side of the electrolyte membrane and the outside is sandwiched between a pair of separators, the fuel cell has a power generation region provided with the electrodes. A fuel cell, characterized in that a cooling fin protruding on the separator is provided on the separator.   The fuel cell according to claim 1, wherein the cooling fin is integrated with the separator.   3. The fuel cell according to claim 1, wherein the power generation region has a rectangular shape, and the cooling fin is provided at a portion corresponding to the long side portion of the rectangular shape.   The fuel cell according to any one of claims 1 to 3, wherein an external cover that covers the periphery of the cooling fin is provided, and a cooling medium is supplied into the external cover.   The fuel cell according to claim 4, wherein the pressure of the cooling medium supplied into the outer cover is set to be equal to or higher than the gas pressure inside the fuel cell.

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