JP4862283B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell.

Conventionally, Patent Document 1 discloses that a lithium battery or the like is covered with an insulating member, for example, a laminate sheet, to prevent electrical connection between the battery and the outside.
JP-A-11-297280

  In the fuel cell stack, water is generated during power generation, and the generated water may come out as water vapor from the fuel cell stack due to deformation of the fuel cell stack due to heat, for example. Therefore, when the outer periphery of the fuel cell stack is covered with an insulating member, water vapor may be condensed between the fuel cell stack and the insulating member, and condensed water may adhere to the insulating member. Further, there is a possibility that water vapor is condensed between the insulating member and the fuel cell stack due to a temperature difference and a humidity difference between the insulating member and the fuel cell stack and the outside of the fuel cell stack via the insulating member. In this case, the insulating member absorbs moisture and swells, so that the insulating member cannot maintain its shape, and thus there is a possibility that the fuel cell stack may be electrically connected to the outside.

  Further, when water vapor adheres to the fuel cell stack, there is a problem that power generation efficiency is reduced in the fuel cell stack.

  The present invention has been invented to solve such problems, and aims to maintain insulation between the fuel cell stack and the outside, and to prevent reduction in power generation efficiency due to condensed water in the fuel cell stack. .

In the present invention, a stack in which unit cells that generate power using fuel gas and oxidant gas are stacked, a current collector plate that sandwiches the stack and takes out power generated by the stack, and at least the outer peripheral surface of the stack and current collector plate from the outside And an insulating member having a moisture permeable portion through which water vapor passes from one surface to the other surface .

  According to the present invention, the outer peripheral surfaces of the stack and the current collector plate are covered with an insulating member, and a moisture permeable portion is provided in the insulating member, so that the insulating member does not absorb moisture leaked from the stack due to, for example, thermal deformation, etc. Therefore, the insulating member can be prevented from being deformed, and the insulation of the fuel cell stack and the outside of the fuel cell stack other than the electrode extraction portion can be improved. Moreover, the production | generation of the condensed water between a stack and an insulating member can be suppressed, and the fall of the power generation efficiency in a stack part can be prevented.

  The configuration of the first embodiment of the present invention will be described with reference to the schematic configuration diagram of FIG. The fuel cell 1 includes, for example, a stack 2 configured by stacking unit cells 20 having solid polymer electrolyte membranes, current collecting plates 3a and 3b provided at both ends of the unit cells in the stacking direction, and current collecting plates 3a and 3b. Insulating plates 4a and 4b provided on the outside, end plates 5a and 5b provided on the further outside of the insulating plates 4a and 4b, and provided on the outer side of one end plate 5a to keep the surface pressure of the stack 2 constant. The pressure plate 6, the end plate 5 b and the pressure plate 6 are connected, the tension plate 7 for stacking the fuel cell 1, and the surface between the end plate 5 a and the pressure plate 6 due to deformation of the stack 2 due to heat or the like. In order to absorb the change in pressure, for example, an elastic member 8 such as a disc spring is provided. Further, an insulating cover 9 is provided so as to cover at least the outer peripheral surfaces of the stack 2 and the current collector plates 3a and 3b. For the sake of explanation, the insulating cover 9 is indicated by a dotted line in FIG.

  Here, the unit cell 20 will be described with reference to the schematic configuration diagram of FIG. The unit cell 20 includes a solid polymer electrolyte membrane (hereinafter referred to as an electrolyte membrane) 21, an anode catalyst layer 22 and a cathode catalyst layer 23 that sandwich the electrolyte membrane 21, and anode gas diffusion provided outside the anode catalyst layer 22. A layer 24, and a cathode gas diffusion layer 25 provided outside the cathode catalyst layer 23. Further, an anode separator 27 provided outside the anode gas diffusion layer 24 and having a hydrogen flow path 30 and a cathode separator 28 provided outside the cathode gas diffusion layer 25 and having an air flow path 31 are provided. Further, an edge seal 29 is provided so that hydrogen or air does not leak. Moreover, the cooling water flow path 32 through which the cooling water for cooling the unit cell 20 flows is provided.

  The end plate 4 b includes a hydrogen introduction manifold 10 that introduces hydrogen into the hydrogen flow path 30, a hydrogen discharge manifold 11 that discharges hydrogen not used for power generation from the anode, and an air introduction manifold 12 that introduces air into the air flow path 31. An air discharge manifold 13 that discharges air that has not been used for power generation from the cathode, a cooling water introduction manifold 14 that introduces cooling water that cools the stack 2, and a cooling water discharge manifold that discharges cooling water from the stack 2. 15.

  Although not shown in detail, the hydrogen introduction manifold 10 and the like are also provided on the insulating plate 4b, the current collector plate 3b, and the stack 2, and the hydrogen introduction manifold 10 and the like communicate with each other in a straight line.

  The insulating cover 9 is disposed so as to cover at least the outer periphery of the stack 2 and the current collecting plates 3a and 3b. This prevents electrical connection between the stack 2 or the current collecting plates 3a and 3b and the outside of the fuel cell 1. The insulating cover 9 is preferably in contact with the stack 2 and the current collector plates 3a and 3b. The insulating cover 9 is waterproof and prevents water from penetrating the stack 2 from the outside of the fuel cell 1. Further, the insulating cover 9 has a waterproof and moisture permeable part 16 in a part thereof.

  The current collecting plates 3a and 3b are provided with a connector (not shown) for taking out the electric power generated in the stack 2 to a power consuming means such as a motor, and the insulating cover 9 is disposed at the place where the connector is provided. do not do. That is, electrical connection between the stack 2 and the current collector plates 3a and 3b other than the connector is prevented, and the fuel cell 1 supplies power to the power consuming means via the connector.

  The waterproof and moisture permeable portion 16 is a member having permeability that allows water vapor (gas) to pass from only one surface to the other surface. In this embodiment, water vapor generated between the insulating cover 9 and the stack 2 is transmitted to the outside of the fuel cell 1 so that water (liquid) does not penetrate the stack 2 from the outside of the fuel cell 1 through the insulating cover 9. Waterproof. As a result, water vapor generated between the stack 2 and the insulating cover 9 is discharged from the stack 2 to the outside of the fuel cell 1 through the waterproof and moisture permeable portion 16, and the stack 2 or the current collector plate 3a, The penetration of water into 3b can be prevented, and further, the electrical connection between the stack 2 or the current collector plates 3a and 3b and the outside of the fuel cell 1 can be prevented. The water vapor permeability of the waterproof and moisture permeable part 16 can be adjusted by the hole diameter and the porosity of the waterproof and moisture permeable part 16.

  The fuel cell 1 generates power using hydrogen and oxygen, and water is generated along with the power generation. Further, hydrogen or air is humidified to prevent the electrolyte membrane 21 from drying. During power generation of the fuel cell 1, the stack 2 and the like are deformed by heat generation, and even when the deformation is absorbed by the elastic member 8, there is a possibility that water vapor leaks to the outside of the stack 2 even though the amount is small. Further, there is a possibility that moisture is condensed between the stack 2 and the insulating cover 9 due to the temperature of the fuel cell 1 or the temperature difference or the humidity difference from the outside of the fuel cell 1 to generate condensed water.

  In this embodiment, the insulating cover 9 prevents electrical connection between the stack 2 or the current collector plates 3a, 3b and the outside of the fuel cell 1, and further, the waterproof cover 16 is provided on the insulating cover 9, thereby stacking the stack. The water vapor between 2 and the insulating cover 9 is transmitted to the outside of the fuel cell 1.

  Further, as shown in FIG. 3, many (large) waterproof and moisture permeable portions 16 may be provided in the insulating cover 9 in the vicinity of the cooling water discharge manifold 15 where the temperature becomes relatively high. That is, the proportion of the waterproof and moisture permeable portion 16 per unit area in the vicinity of the cooling water discharge manifold 15 may be increased as compared with other portions. Moreover, you may enlarge the hole diameter and porosity of the waterproof moisture-permeable part 16 compared with another location.

  Alternatively, as shown in FIG. 4, the proportion of the waterproof and moisture permeable portion 16 per unit area in the vicinity of the air discharge manifold 13 where the temperature is relatively high and the gas having high humidity flows is increased as compared with other portions. Also good. Moreover, you may enlarge the hole diameter and porosity of the waterproof moisture-permeable part 16 compared with another location.

  Accordingly, by increasing the proportion of the waterproof and moisture permeable portion 16 where the condensation tends to occur between the stack 2 and the insulating cover 9, or by increasing the hole diameter and porosity of the waterproof and moisture permeable portion 16, Generation of condensed water with the insulating cover 9 can be further prevented.

  The effect of 1st Embodiment of this invention is demonstrated.

  By covering the stack 2 and the current collector plates 3 a and 3 b of the fuel cell 1 with the insulating cover 9, it is possible to prevent electrical connection between the stack 2, the current collector plates 3 a and 3 b and the outside of the fuel cell 1. .

  By providing the insulating cover 9 with a waterproof and moisture permeable portion 16 that allows water vapor (gas) between the stack 2 and the insulating cover 9 to pass therethrough and prevents moisture from penetrating from the outside of the fuel cell 1, the stack 2 and the insulating cover 9 are provided. 9 can be prevented from condensing moisture, and deformation of the insulating cover 9 due to moisture absorption can be prevented. Further, it is possible to prevent the condensed water condensed between the stack 2 and the insulating cover 9 or the penetration of water from the outside of the fuel cell 1 into the stack 2 and to prevent the power generation efficiency of the fuel cell 1 from being lowered. Can do.

  Since the electrical connection between the fuel cell 1 and the outside can be prevented, the distance between the fuel cell 1 and the outside can be shortened, and a fuel cell system such as a fuel cell vehicle having the fuel cell 1 of this embodiment is provided. It can be made small.

  Next, a second embodiment of the present invention will be described using the schematic configuration diagram of FIG. FIG. 5A is a schematic configuration diagram of the fuel cell unit of this embodiment. FIG. 5B is an enlarged view of FIG. In FIG. 5B, the tension plate 7 is omitted for the sake of explanation, and the round black fill represents condensed water.

  This embodiment includes a fuel cell box 40 that prevents entry of dust and the like from the outside of the fuel cell 1. The fuel cell 1 and the fuel cell box 40 are connected by a connecting portion 41 of an insulating member.

  A part of the fuel cell box 40 has an uneven shape, and the groove bottom 43 and the side surface portion 44 connected to the groove bottom 43 constitute a recess 42. By making a part of the fuel cell box 40 uneven, the surface area of the fuel cell box 40 is increased, and the heat dissipation of heat generated by the power generation reaction of the fuel cell 1 can be improved. In FIG. 5, the concave / convex shape is shown in one place for explanation, but the fuel cell box 40 has a concave / convex shape in addition to this place.

  The distance from the side surface of the fuel cell 1 facing the groove bottom 43 of the concave-convex concave portion 42 provided in the fuel cell box 40, that is, the side surface portion 2a of the stack 2 in which the unit cells 20 are stacked, is shorter than other portions. Therefore, the condensed water tends to adhere to the insulating cover 9 facing the groove bottom 43.

  Therefore, the insulating cover 9 increases the waterproofness of the insulating cover 9 at a location facing the groove bottom 43. Further, when the waterproof / breathable portion 16 is disposed at a location facing the groove bottom 43, the waterproof property of the waterproof / breathable portion 16 is made higher than that at the location not facing the groove bottom 43 (waterproof in FIG. 5B). (The areas that increase the properties are indicated by hatching.)

  Further, as shown in FIG. 6, a vent hole 45 may be provided in the side surface portion 44, and a protruding portion 46 may be provided in the side surface portion 44 on the opening portion 47 side of the recess 42, so that the opening width of the opening portion 47 may be narrowed. That is, the width t 2 of the opening 47 of the recess 42 is made narrower by the protrusion 46 than the width t 1 of the groove bottom 43 in the recess 42. In FIG. 6, the circular black fill represents condensed water.

  As a result, water vapor between the fuel cell box 40 and the fuel cell 1 is discharged from the vent 45 to the outside of the fuel cell box 40, the humidity in the fuel cell box 40 is lowered, and condensation in the fuel cell box 40 is achieved. Water generation can be suppressed. Further, by providing the protruding portion 46, the entry of foreign matter such as dust into the fuel cell box 40 can be suppressed. The protrusion 46 is provided in the recess 42 that is at the upper side in the direction of gravity when the fuel cell box 40 is installed.

  The effect of 2nd Embodiment of this invention is demonstrated.

  The fuel cell 1 includes a fuel cell box 40 that prevents foreign matters such as dust from entering. And the waterproofness of the insulating cover 9 facing the groove bottom 43 of the concave-convex shaped concave portion 42 of the fuel cell box 40 or the waterproof / breathable portion 16 is increased. Since the distance between the groove bottom 43 and the insulating cover 9 is shortened, condensed water is likely to be generated. However, by increasing the waterproof property of the insulating cover 9 or the waterproof / breathable portion 16 at the location facing the groove bottom 43, the insulating cover 9, or the penetration of water into the waterproof and moisture permeable part 16 can be prevented.

A reference example of the present invention will be described with reference to FIG. FIG. 7 is a view showing a part of the insulating cover 50 that is on the upper side in the direction of gravity when the fuel cell 1 is arranged.

  When the fuel cell 1 is disposed, a convex portion 51 is provided on a part of the insulating cover 50 that is on the upper side in the gravity direction, a vent hole 52 is provided on a side surface 51 a that forms the convex portion 51, and a top portion that further forms the convex portion 51. A protrusion 53 is provided on 51b.

  By providing the vent hole 52 on the side surface 51 a of the convex portion 51, water vapor between the stack 2 and the insulating cover 50 can be discharged from the vent hole 52 to the outside of the fuel cell 1.

  The protrusion 53 is provided in a direction that intersects the direction of gravity and intersects the side surface 51a. That is, by providing the protrusion 53 so that the cross section when cut along the stacking direction of the unit cells 20 is substantially T-shaped, water from the vent 52 to the stack 2 and the insulating cover 50 can be removed. Intrusion can be prevented.

  With the above configuration, water vapor between the stack 2 and the insulating cover 50 is discharged to the outside of the fuel cell 1 through the vent 52, and water can be prevented from entering the stack 2 and the insulating cover 50 from the outside. Can do.

  The insulating cover 50 does not have to be provided with the waterproof / breathable portion 16 of the first embodiment.

The effect of the reference example of the present invention will be described.

  A convex portion 51 is provided on a part of the insulating cover 50 located on the upper side in the gravity direction when the fuel cell 1 is arranged, and a vent hole 52 is provided on a side surface 51a of the convex portion 51, whereby the stack 2 and the insulating cover 50 are separated. The water vapor in between can be discharged to the outside of the fuel cell 1. Further, even when the insulating cover 50 is not provided with a permeable waterproof / breathable portion that allows water vapor (gas) to pass only from one surface to the other surface, water vapor is discharged from the vent 52 to the outside of the fuel cell 1. Can do.

  In addition, by providing the protrusion 53 in the direction intersecting the direction of gravity at the top 51 b of the convex portion 51, water can be prevented from entering between the stack 2 and the insulating cover 50.

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea.

  For example, it can be used for fuel cell vehicles.

It is a schematic block diagram of the fuel cell of 1st Embodiment of this invention. It is a schematic block diagram of the unit cell of 1st Embodiment of this invention. It is a schematic block diagram which shows the example of a change of 1st Embodiment of this invention. It is a schematic block diagram which shows the example of a change of 1st Embodiment of this invention. It is a schematic block diagram of the fuel cell unit of 2nd Embodiment of this invention. It is a schematic block diagram which shows the example of a change of 2nd Embodiment of this invention. It is a schematic block diagram of the fuel cell of the reference example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Stack 3a, 3b Current collector plate 5a, 5b End plate 6 Pressure plate 9, 50 Insulation cover 13 Air discharge manifold 15 Cooling water discharge manifold 16 Waterproofing moisture permeable part 20 Unit cell 40 Fuel cell box 42 Recessed part 43 Groove bottom 44 Side face 45 Ventilation hole 46 Projection part 51 Convex part 51a Side face (side face part)
51b Top 52 Vent 53 Projection

Claims (9)

A stack in which unit cells that generate power using fuel gas and oxidant gas are stacked;
A current collector plate that sandwiches the stack and takes out the power generated by the stack;
A fuel cell comprising: an insulating member that covers at least the outer peripheral surface of the stack and the current collector plate so that water does not permeate from the outside and has a moisture permeable portion through which water vapor passes from one surface to the other surface. .   The moisture permeable portion has a water vapor permeability that allows water vapor to pass from the stack to the outside of the insulating member, and a waterproof property that prevents water from penetrating from the outside of the insulating member to the stack. The fuel cell according to claim 1.   3. The fuel cell according to claim 2, wherein the insulating member increases the proportion of the moisture permeable portion as it becomes closer to the oxidant gas discharge manifold through which the oxidant gas discharged from the stack flows. .   4. The fuel cell according to claim 2, wherein the moisture permeable portion increases the water vapor permeability as it comes closer to an oxidant gas discharge manifold through which the oxidant gas discharged from the stack flows. . The stack includes a cooling water flow path through which cooling water for cooling the stack flows.
The said insulating member increases the ratio which the said moisture-permeable part occupies, so that it becomes the vicinity of the cooling water discharge manifold through which the said cooling water discharged | emitted from the said stack flows. A fuel cell according to claim 1. The stack includes a cooling water flow path through which cooling water for cooling the stack flows.
6. The water vapor permeability according to claim 2, wherein the moisture permeable portion increases the water vapor permeability as it becomes closer to a cooling water discharge manifold through which the cooling water discharged from the stack flows. Fuel cell. A fuel cell case containing the fuel cell according to any one of claims 1 to 6 and having a concavo-convex shape at a location facing the insulating member,
  The insulating member has a higher waterproof property of the insulating member facing the groove bottom of the recess of the fuel cell case than the prevention of the insulating member not facing the groove bottom of the recess of the fuel cell case. A fuel cell unit. Containing the fuel cell according to any one of claims 1 to 6;
  It has a concavo-convex shape at a location facing the insulating member,
  A vent on the side surface connected to the groove bottom of the concave-convex recess,
  A fuel cell unit comprising a fuel cell case having a projecting portion that makes an area of an opening of the recess smaller than an area of a groove bottom of the recess. Containing the fuel cell according to any one of claims 1 to 6;
  It has a concavo-convex shape at a location facing the insulating member,
  A vent on the side surface connected to the groove bottom of the concave-convex recess,
  A fuel cell case having a protrusion that narrows the area of the opening of the recess than the area of the groove bottom of the recess,
  The insulating member has a higher waterproof property of the insulating member facing the groove bottom of the recess of the fuel cell case than the prevention of the insulating member not facing the groove bottom of the recess of the fuel cell case. A fuel cell unit.

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