JP2016195017A - Fuel battery stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery stack that makes it difficult for water and dust to accumulate on a gas permeable membrane at a ventilation hole of a case.SOLUTION: The fuel cell stack includes a fuel cell main body including a stacked body 11 formed by stacking a plurality of fuel cell single cells in the stacking direction S, and a case having four side walls and at least one opening surrounding the fuel cell main body along the stacking direction and accommodating the fuel cell main body while compressing it. The four side walls include an upper side wall 22a1 disposed on the upper side when the fuel cell stack is mounted on the moving body. The case is provided with a ventilation part 4 formed on the upper side wall. The ventilation part includes a through hole 40 formed in the upper side wall and communicating the inside and the outside of the case, a through hole 40 formed by the gas permeable film 45 and extending from the periphery of the through hole to the outside of the case so that the gas permeable film is self- A tubular wall portion 41 provided, and a lid portion 42 attached to an outer end of the tubular wall portion.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a fuel cell stack.

  A fuel cell stack, a case main body having an upper side wall that houses the fuel cell stack and mounted on the moving body, and a through hole that is formed upward on the upper side wall and communicates the inside and outside of the case main body And a gas permeable membrane disposed parallel to the surface of the upper side wall so as to cover the through hole, and a protective member disposed so as to cover the gas permeable membrane is disclosed ( For example, see Patent Document 1).

  In the fuel cell stack, hydrogen gas that is a fuel gas may leak from the seal portion to the outside. Therefore, when the fuel cell stack is accommodated in the fuel cell stack case, the hydrogen gas concentration in the fuel cell stack case may increase. Therefore, in Patent Document 1, a through hole is provided in the upper side wall where light hydrogen gas is easily diffused, and the through hole is covered with a gas permeable film. As a result, even when hydrogen gas leaks from the fuel cell stack into the fuel cell stack case, the hydrogen gas diffuses to the outside through the gas permeable membrane from the through hole, so the hydrogen gas concentration in the fuel cell stack case Is kept at a low concentration. However, if the through hole is formed upward on the upper side wall, water or dust tends to accumulate on the gas permeable membrane, the gas permeable membrane may be clogged, and the performance of ventilating hydrogen gas may be deteriorated. Therefore, in Patent Document 1, a protective means is provided on the upper side of the gas permeable film so as to cover the gas permeable film.

JP 2005-149732 A

  By the way, although the details of the fuel cell stack housed in the fuel cell stack case is not described in Patent Document 1, a fuel cell main body including a stacked body in which a plurality of fuel cell single cells are stacked in the stacking direction; And a plurality of plates that surround the fuel cell body while compressing in the stacking direction. For example, when the fuel cell body is a rectangular parallelepiped, the plurality of plates are six plates covering the six faces of the rectangular parallelepiped. In this case, a gasket is inserted between the plates to ensure water tightness. On the other hand, the inventors of the present application can prepare a box-shaped case instead of a plate and store the fuel cell main body in the case, so that the manufacturing cost can be reduced and the productivity can be improved while ensuring water tightness. I found. In this case, since the water tightness of the fuel cell stack is high, it is not necessary to further accommodate the fuel cell stack in a fuel cell stack case as in Patent Document 1.

  However, in this case, hydrogen gas leaks from the fuel cell main body, and there is a possibility that the hydrogen gas stays in a box-shaped case that houses the fuel cell main body. In order to cope with this, the inventors examined the application of a structure for exhausting hydrogen gas from the fuel cell stack case as in Patent Document 1 to a case for housing the fuel cell main body. As a result, even when the protection means (network structure or porous material) of Patent Document 1 is used, water and dust gradually pass through the protection means when viewed in detail, and an amount of water that cannot be ignored in the long term. And found that dust can pass through. When water or dust passes through the protective means, water or dust accumulates on the gas permeable membrane, which may clog the gas permeable membrane and deteriorate the performance of ventilating hydrogen gas. A technique capable of exhausting hydrogen gas in the case without being affected by water or dust is desired.

  According to the present invention, a fuel cell main body including a stack formed by stacking a plurality of fuel cell single cells along the stacking direction, four side walls surrounding the fuel cell main body along the stacking direction, and at least A fuel cell stack having a single opening and a case for accommodating the fuel cell main body, wherein the four side walls are disposed on an upper side when the fuel cell stack is mounted on a moving body. The case includes a ventilation part formed in the upper side wall, the ventilation part being formed in the upper side wall, and a through hole communicating the inside and the outside of the case; A cylindrical wall portion that is formed of a membrane and is erected from the periphery of the through hole to the outside of the case so that the gas permeable membrane is self-supporting; and a lid portion that is attached to an outer end of the cylindrical wall portion; A fuel cell stack comprising It is provided.

  According to the present invention, hydrogen gas in the case can be exhausted without being affected by water or dust.

It is a perspective view of the structural example of a fuel cell stack. It is sectional drawing of the structural example of a fuel cell stack. It is sectional drawing of the structural example of a fuel cell stack. It is a perspective view of the structural example of a ventilation part. It is sectional drawing of the structural example of a ventilation part. It is sectional drawing of the structural example of the gas permeable film of another Example. It is the schematic explaining the effect | action of a ventilation part. It is sectional drawing of the structural example of the ventilation part of another Example. It is sectional drawing of the structural example of the ventilation part of another Example. It is a perspective view of the structural example of the ventilation part of another Example. It is sectional drawing of the structural example of the gas permeable film of another Example. It is a perspective view of the structural example of the fuel cell stack of another Example. It is sectional drawing of the structural example of the gas permeable film of another Example. It is sectional drawing of the structural example of the gas permeable film of another Example.

  The fuel cell stack A according to the example will be described. FIG. 1 is a schematic perspective view of a configuration example of the fuel cell stack A. FIG. The fuel cell stack A includes a fuel cell main body 1 and a case 2 that accommodates the fuel cell main body 1. The case 2 is provided with a plurality of ventilation portions 4 for ventilation in the case 2.

  2 and 3 are schematic cross-sectional views of configuration examples of the fuel cell stack A. FIG. 2 is an E2-E2 cross-sectional view of FIG. 1, and FIG. 3 is an E3-E3 cross-sectional view of FIG. The fuel cell main body 1 includes a stacked body 11, a pair of terminal plates 12, a pair of end plates 14, and a pair of insulating plates 13. The stacked body 11 is formed by stacking a plurality of fuel cell single cells along the stacking direction S. The terminal plate 12 is disposed at both ends of the stacked body 11 in the stacking direction S. The end plate 14 is disposed outside the terminal plate 12 in the stacking direction S. The insulating plate 13 is disposed between the terminal plate 12 and the end plate 14. The terminal plate 12, the end plate 14, and the insulating plate 13 each have a rectangular shape when viewed in a cross section perpendicular to the stacking direction S. At that time, the terminal plate 12 and the insulating plate 13 have substantially the same size. On the other hand, the end plate 14 is approximately the same size as or slightly larger than the terminal plate 12 and the insulating plate 13. The terminal plate 12 and the end plate 14 are made of a conductive material, and the insulating plate 13 is made of an electrically insulating material.

  The case 2 contains the fuel cell main body 1 via the buffer layer 3 and restrains the fuel cell main body 1. The case 2 includes a case main body 22 and a lid plate 21. The case body 22 accommodates the fuel cell body 1 while being compressed in the stacking direction S therein. The case body 22 is substantially a rectangular parallelepiped, has four side walls 22a and a bottom wall 22b surrounding the fuel cell body 1 along the stacking direction S, and has an opening 22c facing the bottom wall 22b. The width of the bottom wall 22 b inside the case body 22 is slightly larger than the cross section perpendicular to the stacking direction S of the fuel cell body 1. The length in the stacking direction S inside the case body 22, that is, the depth, is the same as or slightly longer than the length in the stacking direction S when the fuel cell body 1 is compressed in the stacking direction S. The lid plate 21 is a lid of the case body 22 and is fastened to the case body 22 by a fastening member (not shown) so as to close the opening 22c of the case body 22. The case body 22 and the lid plate 21 are made of a metal such as stainless steel or aluminum. In the embodiment shown in FIGS. 2 and 3, the side wall 22a and the bottom wall 22b are substantially flat side walls. However, in another embodiment (not shown), at least one of the side wall 22a and the bottom wall 22b is partially or entirely. A side wall having a curved surface. In still another embodiment (not shown), the fuel cell main body 1 is accommodated in the case 2 without being compressed in the stacking direction S.

  The four side walls 22a of the case body 22 include an upper side wall 22a1 disposed on the upper side when the fuel cell stack A is mounted on a moving body such as a vehicle, a lower side wall 22a2 disposed on the lower side, and an upper side wall 22a1. And lateral side walls 22a3 and 22a4 connecting the lower side wall 22a2. The ventilation part 4 is formed in the upper side wall 22a1. The ventilation unit 4 communicates the inside and the outside of the case 2 so that a gas such as hydrogen gas or air flows but water does not flow. In the embodiment shown in FIG. 2, five ventilation parts 4 are arranged on the upper side wall 22a1. However, the number of the ventilation parts 4 can be increased / decreased according to the quantity of the gas ventilated.

  When the fuel cell main body 1 is accommodated in the case main body 22, the lid plate 21 closes the opening 22c, and the case main body 22 and the lid plate 21 are fastened by a fastening member, the fuel cell main body 1 is separated from the lid plate 21 and the case. The bottom wall 22b of the main body 22 is pushed and restrained from both sides in the stacking direction S. As a result, the end plates 14 and 14 on both sides of the fuel cell main body 1 approach each other in the stacking direction S. Therefore, the stacked body 11, the terminal plate 12, the insulating plate 13, and the end plate 14 are in close contact with each other in the stacking direction S. At this time, a gap G having a distance D is formed between the outer peripheral surface 1a of the fuel cell main body 1 along the stacking direction S and the inner peripheral surface 2a of the side wall 22a of the case 2 facing the outer peripheral surface 1a. When the depth of the case body 22 is slightly longer than the length of the compressed fuel cell body 1 in the stacking direction S, the bolt is tightened from the outside of the bottom wall 22b of the case body 22 and protrudes from the inside of the bottom wall 22b. The bolts press the end plate 14 of the fuel cell body 1 to restrain the fuel cell body 1.

  The buffer layer 3 absorbs the impact applied to the fuel cell main body 1, suppresses the displacement of the fuel cell main body 1, electrically insulates the fuel cell main body 1 and the case 2, and changes the dimension changed by the external force to the original. It is a member having a restoring force to return to dimensions. The buffer layer 3 preferably further has a dilatant characteristic that exhibits fluidity at a slow input load, deforms slowly, behaves like a solid at an abrupt input load, and hardly deforms. The buffer layer 3 is disposed in a compressed state between the fuel cell main body 1 and the case 2, that is, in the gap G. 2 and 3, the buffer layer 3 is provided from one end to the other end of the fuel cell body 1 along the stacking direction S when viewed in the stacking direction S (FIG. 2). When viewed in a direction perpendicular to S (FIG. 3), it is provided at least in the vicinity of the four corners Cn of the fuel cell body 1. Examples of the material of the buffer layer 3 include a mixture of a resin and a solid material such as a mixture of silicone oil and boric acid or a mixture of silicone resin and silica.

  The lid plate 21, the terminal plate 12, the insulating plate 13, and the end plate 14 positioned at one end in the stacking direction S of the fuel cell stack A penetrate the plates in the stacking direction S from the outside of the fuel cell stack A. Are provided with a plurality of flow paths (not shown). In these flow passages, a supply path for supplying fuel gas to the stacked body 11, a discharge path for discharging fuel gas from the stacked body 11, a supply path for supplying oxidant gas to the stacked body 11, and an oxidant gas for the stacked body 11 A discharge path for discharging the cooling water, a supply path for supplying cooling water to the stacked body 11, and a discharge path for discharging cooling water from the stacked body 11.

  Each single fuel cell has an anode electrode and a cathode electrode (not shown), and the anode electrode is electrically connected to the cathode electrode of the fuel cell unit cell adjacent to one side, and the cathode electrode is adjacent to the other side. It is electrically connected to the anode electrode of the single fuel cell. The anode electrode at one end of the laminate 11 is electrically connected to one terminal plate 12, and the cathode electrode at the other end is electrically connected to the other terminal plate 12. A single fuel cell generates electric power by an electrochemical reaction between a fuel gas (for example, hydrogen gas) supplied to the anode electrode of the fuel cell and an oxidant gas (for example, air) at the cathode electrode. The electric power generated in the plurality of fuel cell single cells is taken out of the fuel cell stack A through a plurality of wires extending from the terminal plate 12 to the outside of the fuel cell stack A. The electric power extracted from the fuel cell stack A is supplied to, for example, an electric motor for driving a vehicle or a capacitor. The end plate 14 and the case 2 are grounded. Note that illustration of these electrical configurations is omitted.

  4 is a perspective view showing a configuration example of the ventilation unit 4, and FIG. 5 is a cross-sectional view showing a configuration example of the ventilation unit 4 attached to the fuel cell stack A. As shown in FIG. However, FIG. 5 shows a cross section perpendicular to the upper side wall 22a1. The ventilation unit 4 forms a hydrogen gas flow path from the inside of the case 2 to the outside while preventing water from entering from the outside to the inside of the case 2. Thereby, the hydrogen gas leaked from the fuel cell main body 1 to the inside of the case 2 can diffuse outside the case 2 without staying inside the case 2.

  The ventilation unit 4 is formed in the upper side wall 22a1, and is formed by a through hole 40 that communicates the inside and outside of the case 2 and the gas permeable film 45. From the periphery of the through hole 40 so that the gas permeable film 45 is self-supporting. A cylindrical wall portion 41 erected to the outside of the case 2 and a lid portion 42 attached to the outer end of the cylindrical wall portion 41 are provided. In the embodiment shown in FIG. 4, a cylindrical gas permeable membrane 45 is erected along the peripheral edge of the circular through hole 40. In still another embodiment (not shown), the shape of the through hole 40 is another shape such as an ellipse or a polygon.

  In the embodiment shown in FIG. 4, the cylindrical wall portion 41 includes a plate-like base material 43 provided on the upper side wall 22 a 1 at the periphery of the through hole 40. The base material 43 is fixed to the upper side wall 22a1 by a fastener 44, whereby the cylindrical wall portion 41 is fixed to the upper side wall 22a1. Further, in the embodiment shown in FIG. 5, the base material 43 is formed with an insertion groove 43 h formed so as to surround the through hole 40. The end 45p1 of the gas permeable membrane 45 is inserted into the insertion groove 43h and fixed by an adhesive or welding, so that the gas permeable membrane 45 stands in a cylindrical shape from the base material 43 to the outside of the case body 22 so as to be self-supporting. Established. An insertion groove 42h is formed in the lid portion 42 so as to face the insertion groove 43h. The lid portion 42 is supported by the cylindrical wall portion 41 by inserting the distal end 45p2 which is the outer end portion of the gas permeable membrane 45 into the insertion groove 42h and fixing it by an adhesive or welding. In another embodiment (not shown), the base material 43 is joined to the upper side wall 22a1 by welding or an adhesive. In still another embodiment (not shown), the cylindrical wall portion 41 does not have the base material 43, and the gas permeable film 45 is inserted into the insertion groove provided on the upper side wall 22a1 of the peripheral edge of the through hole 40, and the adhesive. Or it is fixed by welding or the like. In still another embodiment (not shown), the cylindrical wall portion 41 does not have the base material 43, and the gas permeable membrane 45 is inserted into the through hole 40 so as to be in contact with the inner peripheral edge of the through hole 40, and is adhesive or welded. It is fixed by etc.

  The base material 43 and the lid part 42 of the cylindrical wall part 41 are formed of a material that does not allow gas or liquid to permeate, for example, a metal such as stainless steel or aluminum, or a synthetic resin such as engineering plastic. In the embodiment shown in FIG. 5, aluminum is used. The gas permeable membrane 45 is formed of a material that allows gas such as hydrogen gas or air to pass therethrough but does not pass water. For example, Poeflon (registered trademark) manufactured by Sumitomo Electric Industries, Ltd. can be used. The gas permeable membrane 45 has such a thickness that it can stand upright when it is cylindrical. In the embodiment shown in FIG. 5, the gas permeable membrane 45 is a single layer, but in another embodiment shown in FIG. 6, the gas permeable membrane 45 includes a plurality of gas permeable membranes 45a stacked on each other in the thickness direction SP. ˜45c. In FIG. 6, three layers of gas permeable membranes 45a to 45c are stacked. However, the number of layers is not particularly limited, and may be two layers or four or more layers. In another embodiment (not shown), the gas permeable film 45 is formed by laminating a supporting film on a gas permeable film in the thickness direction. Examples of the supporting film include a porous film formed of a synthetic resin, ceramics, or metal.

  When hydrogen gas leaks from the fuel cell main body 1 to the inside of the case 2, as shown in FIG. 7, the hydrogen gas mainly diffuses upward through the case 2 while flowing through the gap G, and passes through the through hole 40 to the ventilation unit 4. Enter. In the ventilation unit 4, the hydrogen gas diffuses outside the case 2 via the gas permeable membrane 45. Thereby, hydrogen gas does not stay inside the case 2, and the hydrogen gas concentration inside the case 2 is kept at a low concentration. Thus, since the ventilation part 4 is arrange | positioned in the upper side wall 22a1 of the case 2 where light hydrogen gas tends to gather, hydrogen gas can be efficiently and reliably exhausted outside the case 2 through the ventilation part 4.

  In the embodiment shown in FIG. 5, the gas permeable membrane 45 is erected substantially perpendicular to the upper side wall 22a1. Therefore, it is difficult for water and dust to adhere, and even if it adheres, it is difficult to fall and accumulate. Thereby, water and dust are prevented from adhering to and accumulating on the gas permeable film 45, and hydrogen gas is exhausted satisfactorily.

  In another embodiment shown in FIG. 8, the gas permeable membrane 45 is erected at an acute angle with respect to the upper side wall 22a1, that is, the gas permeable membrane 45 spreads from the end 45p1 toward the tip 45p2. The acute angle in this case is an angle at which the gas permeable membrane 45 can stand on its own, and is, for example, 60 degrees or more. At this time, compared to the embodiment shown in FIG. 5, it becomes more difficult for water and dust to adhere, thereby suppressing the water and dust from adhering to and accumulating in the gas permeable film 45. Exhaust is performed well.

  In another embodiment shown in FIG. 9, the gas permeable membrane 45 is erected at an obtuse angle with respect to the upper side wall 22a1, that is, the gas permeable membrane 45 is squeezed from the end 45p1 toward the tip 45p2. The obtuse angle in this case is an angle at which the gas permeable membrane 45 can stand on its own, for example, 120 degrees or less. At this time, compared to Patent Document 1, it becomes difficult for water and dust to adhere, thereby preventing water and dust from adhering to and accumulating on the gas permeable film 45, and exhausting hydrogen gas better. Done.

  Moreover, as another ventilation part, the side wall standing upright from the periphery of the through-hole 40 of upper side wall 22a1, the cover part which covers the upper part of the side wall, the through-hole formed in the side wall, and the through-hole It is conceivable to have a gas permeable membrane covering In this ventilation part, the gas permeable membrane is not self-supporting, and the side wall is used as a support member for the gas permeable membrane. On the other hand, in the embodiment shown in FIG. 5, the gas permeable membrane 45 is erected so as to be self-supporting, and no support member other than the base material 43 is used. That is, compared with the said other ventilation part, the area which the hydrogen gas permeate | transmits in the gas permeable film 45 can be taken more widely by the part which the said side wall does not exist. Thereby, the efficiency of exhausting hydrogen gas can be increased.

  Next, another embodiment will be described with reference to FIGS.

  FIG. 10 is a perspective view showing a configuration example of the ventilation unit 4 of another embodiment, and FIG. 11 is a cross-sectional view showing a configuration example of the gas permeable membrane 45 in FIG. However, FIG. 11 shows a cross section parallel to the upper side wall 22a1 in the gas permeable membrane 45 when the ventilation unit 4 is installed in the case body 22. The cross section of the gas permeable film 45 parallel to the upper side wall 22a1 has a shape in which the concave portions 51b and the convex portions 51a are alternately continued along the circumferential direction Q, that is, the concave and convex shape 51.

  Incidentally, the cross section of the gas permeable film 45 shown in FIG. 4 parallel to the upper side wall 22a1 has a circular shape. Here, the circular shape of the cross section of the gas permeable film 45 shown in FIG. 4 is, for example, a circular shape 50 circumscribing the uneven shape 51 shown in FIG. In this case, the area required for installation of the uneven shape 51 is substantially the same as the area required for installation of the circular shape 50. Here, the circumferential length of the concavo-convex shape 51 can be made larger than the circumferential length of the circular shape 50 by appropriately selecting the degree of depression of the concave portion 51 b of the concavo-convex shape 51. Accordingly, if the height of the gas permeable film 45 is constant, the area of the gas permeable film 45 having the concavo-convex shape 51 can be made larger than the area of the gas permeable film 45 having the circular shape 50. In other words, the area of the gas permeable film 45 in FIG. 11 is increased more than the area of the gas permeable film 45 in FIG. Can do. That is, by using the gas permeable membrane 45 shown in FIG. 11, the ventilation part 4 shown in FIG. 10 can improve the ventilation efficiency in the case 2 compared with the ventilation part 4 shown in FIG.

  FIG. 12 is a perspective view showing a configuration example of a fuel cell stack A of another embodiment. The fuel cell stack A shown in FIG. 12 is different from the fuel cell stack A shown in FIG. 1 in that the ventilation unit 4 shown in FIG. 10 is used as the ventilation unit and the number of ventilation units 4 is small. Since the ventilation unit 4 shown in FIG. 10 improves the ventilation efficiency in the case 2 compared to the ventilation unit shown in FIG. 4, the fuel cell stack A shown in FIG. 12 is different from the fuel cell stack A shown in FIG. In comparison, the number of ventilation parts 4 can be reduced. Thereby, since the number of the through-holes 40 can be reduced, the fall of the rigidity of the case main body 22 by installation of the ventilation part 4 can be suppressed. Moreover, since the material of the ventilation part 4 can be reduced, the cost of the ventilation part 4 can be reduced. Moreover, since the height of the gas permeable membrane 45 can be reduced and the area required for installation can be reduced, the overall size of the ventilation unit 4 can be reduced, the material of the ventilation unit 4 can be reduced, and the ventilation unit 4 can be reduced. Cost can be reduced.

  However, the number and size of the concave portions 51b and the convex portions 51a in the concavo-convex shape 51 of the gas permeable film 45 are not limited to the example shown in FIG. For example, the number of the recesses 51b and the protrusions 51a is 7 in the embodiment shown in FIG. 11, but 10 in the embodiment shown in FIG. 13 and 16 in the embodiment shown in FIG. There may be more than the embodiment shown in FIG. Further, the innermost portion 51bb of the recess 51b may be adjacent to the through hole 40 as shown in FIGS. 11 and 14, or may be separated from the through hole 40 as shown in FIG. In the example shown in FIGS. 11 and 14, the length L of one side of the gas permeable film 45 forming the concavo-convex shape 51 can be made longer than in the example shown in FIG. The area can be increased.

DESCRIPTION OF SYMBOLS 1 Fuel cell main body 2 Case 4 Ventilation part 11 Laminated body 22a Side wall 22a1 Upper side wall 22c Opening 40 Through-hole 41 Cylindrical wall part 45 Gas permeable film 42 Lid part A Fuel cell stack S Stacking direction

Claims (3)

A fuel cell main body including a laminate formed by laminating a plurality of fuel cell single cells along the lamination direction;
A case having four side walls and at least one opening surrounding the fuel cell body along the stacking direction, and housing the fuel cell body;
A fuel cell stack comprising:
The four side walls include an upper side wall disposed on the upper side when the fuel cell stack is mounted on a moving body,
The case includes a ventilation part formed on the upper side wall,
The ventilation section is
A through hole formed in the upper side wall and communicating between the inside and the outside of the case;
A cylindrical wall portion formed of a gas permeable membrane and erected from the periphery of the through hole to the outside of the case so that the gas permeable membrane is self-supporting;
A lid attached to the outer end of the cylindrical wall,
Comprising
Fuel cell stack. The cross section of the cylindrical wall portion parallel to the upper side wall has a shape in which concave portions and convex portions are alternately continued along the circumferential direction.
The fuel cell stack according to claim 1. The gas permeable membrane is formed from a plurality of gas permeable membranes laminated together in the thickness direction.
The fuel cell stack according to claim 1 or 2.

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