JP2005158339A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ventilate the inside of a fuel cell stack case efficiently to evacuate residual hydrogen. <P>SOLUTION: In the fuel cell having a pair of fuel cell stacks 4 formed by laminating a plurality of fuel cells, and a stack case 2 for storing the pair of fuel cell stacks 4 therein, the pair of fuel cell stacks 4 are arranged in parallel while being inclined so that an upper side interval is longer than a lower side interval, and the stack case 2 has an air introducing part 8a formed near the top of one end face in both end faces 5b in the laminated direction of the fuel cells, and an air evacuation part 8b formed near the top of the other end face. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell housed in a stack case.

  In a fuel cell system, a fuel cell stack is used in a case made of metal or the like. In addition, unreacted hydrogen (residual hydrogen) that has not been used for the reaction and high-temperature and high-humidity exhaust air are discharged from the fuel cell stack during power generation.

Therefore, it is necessary to ventilate the case in order to reduce the risk of explosion due to the high unreacted hydrogen concentration in the case. Patent Document 1 discloses a technique for ventilating a case by providing a blower in the case.
JP-A-11-185781

  However, the technique described in Patent Document 1 does not consider the pressure loss of the ventilation flow by the blower and the flow of residual hydrogen. Therefore, in order to perform ventilation necessary for diluting hydrogen, the size of the blower is increased. The drive power needs to be increased, resulting in problems such as an increase in the size of the entire device and a decrease in the output of the battery system.

  Therefore, an object of the present invention is to efficiently ventilate the case with a low pressure loss.

  The fuel cell of the present invention is a fuel cell having a pair of fuel cell stacks in which a plurality of fuel cell cells are stacked, and a stack case that houses the pair of fuel cell stacks, wherein the pair of fuel cell stacks includes: The stack cases are arranged in parallel and inclined so that the upper interval is larger than the lower interval, and the stack case has air in the vicinity of the uppermost portion of one of the end surfaces in the stacking direction of the fuel cells. The introduction part has an air discharge part near the uppermost part of the other end face.

  According to the present invention, the hydrogen gas leaked from the fuel cell stack has a low specific gravity and accumulates near the upper center of the stack case.For example, using the blowing means, among the stack case end surfaces in the fuel cell stacking direction, By introducing air from the introduction part provided near the upper center of one end face and exhausting it from the discharge part provided near the upper center of the other end face, the hydrogen gas accumulated near the upper center is removed from the ventilation air. At the same time, it is discharged outside the case.

  That is, it is possible to efficiently ventilate the interior without providing a complicated air passage.

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

  FIG. 1 is a cross-sectional view of a stack case according to the present embodiment, 4 is a fuel cell body (hereinafter referred to as a stack) formed by stacking a plurality of fuel cells, and 5 is open at the top. A stack case container for accommodating the stack 4 therein, 1 is a stack case lid for closing the opening of the stack case 5, and 3 is an insulating material for electrically insulating the stack 4 and the stack case container 5.

  In the stack case container 5, the two stacks 4 are stored in an inclined manner so as to form a so-called V-shape in which the fuel cell stacking direction is substantially parallel and the distance between the stacks increases upward. Further, the insulating material 3 is disposed so as to cover the outer side surface and the upper surface of the stack 4, and the opening is closed by the stack case lid 1.

  A combination of the stack case container 5 and the stack case lid 1 is referred to as a stack case 2. Of the surfaces forming the outer shell of the stack case 2, the surface closed by the stack case lid 1 is the upper surface 13, the surface facing the upper surface is the bottom surface 14, the surface parallel to the fuel cell stacking direction is the side surface 5 a, and the fuel A surface orthogonal to the battery stacking direction is defined as an end surface 5b.

  The stack case 2 is generally formed so as to cover a pair of stacks 4 arranged in a V shape when viewed from the fuel cell stacking direction with a certain distance from the periphery of the stack 4. 13 is formed in a convex shape having an inclined surface inclined at substantially the same angle as the top surface of the stack 4 with the central portion as a vertex, and the bottom surface 14 is similarly formed in a concave shape with the central portion as a vertex. .

  A space 12 is formed between the two stacks 4 arranged in parallel along the center line Z of the stack case 2 so that its width increases as it goes upward.

  The insulating material 3 covers the stack case 2 so that the stack 4 cannot be completely seen when viewed from above, and is disposed with a gap between the stack 4 and the inner wall surface of the stack case 2.

  A groove extending in the front-rear direction of the case is provided at an end portion of the bottom surface 14 of the stack case 2 substantially parallel to the fuel cell stacking direction, that is, a portion where the side surface 5a and the bottom surface 14 of the stack case 2 intersect with each other. And The drainage groove 7 may be formed by projecting a part of the bottom surface 14 by molding or the like, or may be formed by scraping a part of the bottom surface 14 into a groove shape.

  2 is a front view of the stack case 2 (viewed from the battery cell stacking direction), and FIG. 3 is a side view (viewed from a direction substantially orthogonal to the stacking direction).

  A ventilation introduction hole 8a is provided in one end face 5b near the upper center of the stack case 2 and a ventilation discharge hole 8b is provided in the other, and air is blown from the ventilation introduction hole 8a toward the ventilation discharge hole 8b by a blower or the like (not shown). Ventilate by flowing. Since there is no airflow resistance such as the stack 4 between the ventilation introduction hole 8a and the ventilation discharge hole 8b, most of the air introduced from the ventilation introduction hole 8a flows directly toward the ventilation discharge hole 8b. Discharged.

  Further, a drain drain hole 9 is provided in the vicinity of the lowermost portion of one end face of the stack case 2 so as to communicate the drain groove 7 with the outside. Reference numeral 11 denotes a manifold for piping for supplying hydrogen and air for power generation reaction to the stack 4 and piping for supplying and exhausting air.

  With the above configuration, the hydrogen gas leaking from the stack 4 has a low specific gravity, and therefore moves upward in the stack case 2 as indicated by arrows a and b in FIG. Since a large amount of air flows from the ventilation introduction hole 8a toward the ventilation discharge hole 8b in the upper part of the space 12, the leaked hydrogen gas is discharged together with the air from the ventilation discharge hole 8b.

  That is, the hydrogen gas in the stack case 2 can be reliably discharged by simply flowing air straight through the portion near the top of the stack case 2 where the ventilation resistance is low.

  Thereby, compared with the case where it ventilates by providing the complicated path | route for ventilation in the stack case 2, for example, the pressure loss of the airflow for ventilation can also be suppressed low, and a fan can be small.

Further, since the upper surface 13 and the bottom surface 14 of the stack case 2 are inclined, the water droplets 6a and 6c condensed on the inner wall surface of the upper surface 13 due to a temperature difference between the inside and outside of the stack case 2 are transmitted along the inner wall surface according to the inclination. Accumulate in the drains 7. Even if you drop it along the inner wall,
Since the insulating material 3 covers the stack 4, water droplets are not applied to the stack 4. Then, the water droplets that have fallen on the insulating material 3 are collected in the drain groove 7 along the upper surface of the insulating material 3.

  As described above, since most of the water condensed in the stack case 2 is accumulated in the drainage groove 7, only the drainage drain hole 9 is provided in the drainage groove 7, and almost all the condensed water droplets are discharged to the outside. can do.

  As described above, in the present embodiment, the upper surface 13 and the lower surface 14 of the stack case 2 have a convex shape upward, and the pair of stacks 4 are inclined so as to increase in parallel as the distance between both stacks increases upward. Therefore, the hydrogen gas leaking from the stack 4 has a low specific gravity and therefore gathers in the vicinity of the apex of the convex shape that is the highest position in the stack case 2. As a result, the internal hydrogen can be obtained simply by flowing air from the ventilation introduction hole 8a provided near the upper end of one end surface 5b of the stack case 2 toward the ventilation discharge hole 8b provided near the upper end of the other end surface 5b. Gas can be efficiently discharged from the ventilation discharge hole 8b. Therefore, it is possible to prevent an increase in the size of the ventilation fan, an increase in the amount of power used, a decrease in output as a fuel cell system, and the like.

  Since a gap is provided between the insulating material 3 and the inner wall surface of the stack case 2, no electric leakage occurs even if dew condensation occurs on the inner surface of the stack case 2.

  Further, since the insulating material 3 is disposed so as to completely cover the upper surface of the stack 4 when viewed from above the stack case 2, even if water droplets condensed on the inner wall surface of the stack case 2 are dropped, the stack 4 is not damaged. There is no leakage.

  Since the upper surface 13 and the bottom surface 14 of the stack case 2 are convex upward, the condensed water drops flow along the inclined surface and collect in the drain grooves 7 provided on the bottom surface 13 of the stack case 2. It is possible to smoothly drain water simply by providing the drainage drain hole 9 that communicates.

  Note that the side surface 5a of the stack case 2 does not necessarily have to be substantially parallel to the side surface of the stack 4 as shown in FIG. 1, and may be vertically downward.

  Further, the upper surface 13 of the stack case 2 may be a horizontal plane. Even if the top surface 13 is a horizontal plane, if the gap between the stack 4 and the insulating material 3 or the gap between the stack 4 and the bottom surface 14 is inclined toward the upper center of the stack as described above, the hydrogen gas generated from the stack 4 is Accumulate near the upper center of the stack case 2. Therefore, if the ventilation introduction hole 8a and the ventilation exhaust port 8b are provided in the portion where the hydrogen gas accumulates, efficient ventilation can be performed.

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

  The present invention is applicable to a fuel cell power generation system.

It is sectional drawing of the stack case of this embodiment. It is a figure showing the structure of the stack case of this embodiment. It is a side view of the stack case of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stack case cover 3 Electric insulation material 4 Stack 5 Stack case container 7 Drainage groove 8a Ventilation introduction hole 8b Ventilation discharge hole 9 Drain drain hole 13 Ceiling part 14 Bottom part

Claims (4)

A pair of fuel cell stacks in which a plurality of fuel cells are stacked;
In a fuel cell having a stack case that houses the pair of fuel cell stacks therein,
The pair of fuel cell stacks are arranged in parallel and inclined so that the upper interval is larger than the lower interval,
The stack case has an air introduction part near the uppermost part of one end face, and an air discharge part near the uppermost part of the other end face, of both end faces in the stacking direction of the fuel cells. battery.   The fuel cell according to claim 1, wherein grooves extending in the fuel cell stacking direction are provided at both ends of the bottom of the stack case.   3. The fuel according to claim 1, wherein an electrical insulating material is provided between an upper surface and a side surface of the pair of fuel cell stacks and an inner surface of the stack case to cover an upper portion of the fuel cell stack and a part of the side surface. battery.   The fuel cell according to any one of claims 1 to 3, wherein a bottom portion of the stack case is formed to be inclined so as to be substantially parallel to the bottom surfaces of the pair of fuel cell stacks.

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