Ventilation unit and fuel cell ventilation device

Abstract

A ventilation unit according to the present invention is attached to a housing so as to cover an opening that communicates an internal space of the housing with an external space, and comprises: a filter disposed facing a surface of the housing so as to cover the opening; a frame-shaped holding member attached to the housing while holding a peripheral edge part of the filter and provided with a ventilation opening having substantially the same shape as the opening; and a cover attached to the holding member so as to cover the inside of the peripheral edge part of the filter. The holding member has a plurality of fixing parts which are provided along a peripheral edge part of the holding member and are for fixing the holding member to the housing. The ventilation opening extends in a region between a pair of the fixing parts among the plurality of fixing parts.

Description

Ventilation Unit and Ventilation Device for Fuel Cell

[0001] The present invention relates to a ventilation unit and a ventilation device for a fuel cell.

[0002] In recent years, in order to enable more people to have affordable, reliable, sustainable, and advanced energy access, technological developments related to fuel cells that contribute to energy efficiency have been carried out. As a ventilation device used in this type of fuel cell, conventionally, a device has been known in which a filter is arranged to cover an opening in the front surface of a fuel cell case, and a cover member is attached to the front surface of the fuel cell case via a pressing member (see, for example, Patent Document 1). In the device described in Patent Document 1, a plurality of leg portions project upward and downward from the peripheral edge of the cover member, and the cover member is fixed to the front surface of the fuel cell case by bolts passing through the leg portions.

[0003] Japanese Unexamined Patent Application Publication No. 2022 - 126924

[0004] It is preferable that this type of ventilation device is configured compactly as a whole including the mounting area of the ventilation device. However, if a plurality of leg portions project from the peripheral edge of the cover member as in the device described in Patent Document 1 above, it is difficult to configure the entire ventilation device compactly.

[0005] One aspect of the present invention is a ventilation unit attached to a housing so as to cover an opening that communicates an internal space and an external space of the housing, including a filter disposed facing the surface of the housing so as to cover the opening, a frame-shaped holding member provided with a ventilation opening having substantially the same shape as the opening and attached to the housing while holding the peripheral edge of the filter, and a cover attached to the holding member so as to cover the inside of the peripheral edge of the filter. The holding member has a plurality of fixing portions provided along the peripheral edge of the holding member for fixing the holding member to the housing, and the ventilation opening extends in a region between a pair of the fixing portions among the plurality of fixing portions.

[0006] Another embodiment of the present invention provides a fuel cell ventilation system comprising: a fuel cell case housing a laminate of multiple power generation cells stacked on top of each other; a ventilation unit attached to the fuel cell case so as to cover an opening that connects the internal space of the fuel cell case to the external space; and a fixing member for fixing the ventilation unit to the fuel cell case. The ventilation unit has a filter positioned facing the surface of the fuel cell case so as to cover the opening; a frame-shaped holding member attached to the fuel cell case while holding the periphery of the filter, and having a ventilation opening substantially the same shape as the opening; and a cover attached to the holding member so as to cover the inside of the periphery of the filter. The holding member has a plurality of fixing parts provided along the periphery of the holding member on which the fixing member is positioned, and the ventilation opening extends into the region between a pair of fixing parts among the plurality of fixing parts.

[0007] According to the present invention, the ventilation unit can be configured compactly.

[0008] A schematic perspective view showing the overall configuration of a fuel cell stack equipped with a ventilation device for a fuel cell according to an embodiment of the present invention. A cross-sectional view showing the main components of the fuel cell stack when another case is provided above the fuel cell case of Figure 1. A perspective view showing the configuration of the mounting portion for the ventilation unit provided on the left wall of the fuel cell case of Figure 1. A front view of the case opening of Figure 3. A front view showing the ventilation unit according to an embodiment of the present invention attached to the fuel cell case. A cross-sectional view along the line VI-VI of Figure 5. A cross-sectional view along the line VII-VII of Figure 5. A perspective view showing the main components of the ventilation unit according to an embodiment of the present invention. A rear view of the ventilation unit according to an embodiment of the present invention. A perspective view of the cover constituting the ventilation unit according to an embodiment of the present invention. A rear view of the cover of Figure 10. A cross-sectional view along the line XII-XII of Figure 11.

[0009] Embodiments of the present invention will be described below with reference to Figures 1 to 12. The fuel cell ventilation system according to the embodiment of the present invention can be applied, for example, to various mobile vehicles equipped with fuel cells. Below, an example of applying the fuel cell ventilation system to a fuel cell vehicle that runs using electricity generated by a fuel cell will be described. The fuel cell vehicle has a fuel cell stack, which is composed of multiple power generation cells stacked together, as the main component of the fuel cell. The fuel cell ventilation system according to this embodiment is provided on the fuel cell stack.

[0010] Figure 1 is a schematic perspective view showing the overall configuration of the fuel cell stack 100 on which the fuel cell ventilation device 1 according to this embodiment is provided. For convenience, the three mutually orthogonal axial directions shown in the figure will be defined as the front-rear direction, the left-right direction, and the up-down direction, and the configuration of each part will be described according to this definition. The downward direction in the up-down direction corresponds to the direction of gravity. The front-rear direction and the left-right direction coincide, for example, with the front-rear direction and the left-right direction of a vehicle. The fuel cell stack 100 is installed, for example, at the front of a vehicle, so that airflow can pass around it.

[0011] As shown in Figure 1, the fuel cell stack 100 comprises a cell stack (stack) 110, substantially rectangular end plates 120 positioned at both ends of the cell stack 110 in the front-rear direction, and a case (fuel cell case) 130 surrounding the cell stack 110. The case 130 has four substantially rectangular plate-shaped side walls, namely an upper wall 131 and a bottom wall 132 positioned at the top and bottom and extending substantially horizontally, and a left wall 133 and a right wall 134 positioned on the left and right sides and extending substantially vertically. The four side walls 131 to 134 are made of metal such as iron or aluminum and are formed, for example, by casting. The ends of four adjacent side walls 131 to 134 are fastened together by bolts (not shown), and the fuel cell stack 100 as a whole takes on a substantially rectangular parallelepiped shape.

[0012] Another roughly rectangular case 130A, as shown by the dashed line, can be provided above case 130. In this case, the lower case 130 (lower case) and the upper case 130A (upper case) together constitute the fuel cell case. Figure 2 is a cross-sectional view showing the main components of the fuel cell stack 100 when case 130A is provided above case 130. As shown in Figure 2, a communication port 131a is opened in the upper wall 131 of case 130. The internal space SP1 of case 130 (the space between case 130 and the cell stack 110) and the internal space SP2 of case 130A communicate with each other via the communication port 131a. The upper internal space SP2 houses a control unit (e.g., a voltage control unit) that controls the operation of the fuel cell.

[0013] Part A of Figure 1 shows a section of the upper wall 131 of the case 130 that has been cut away. As shown in Part A of Figure 1, the cell stack 110 is constructed by stacking multiple power generation cells 111 (for convenience, only a single power generation cell 111 is shown) in the front-to-back direction, and the whole structure has a roughly rectangular parallelepiped shape.

[0014] The power generation cell 111 includes a unitized electrode assembly (UEA) 112 having a membrane electrode assembly containing an electrolyte membrane and electrodes, and separators 113 positioned on both the front and rear sides of the UEA 112, sandwiching the UEA 112. The UEA 112 and the separators 113 are arranged alternately in the front-rear direction. The separator 113 has a pair of thin metal plates with a corrugated cross-section, and the outer periphery of these plates is joined together to form a single unit. Cooling channels are formed inside the pair of plates through which a cooling medium (e.g., water) flows, and the power generation surface of the power generation cell 111 is cooled by the flow of the cooling medium. The UEA 112 can also be called a membrane electrode structure.

[0015] The separator 113 on the front side of the UEA 112 is, for example, an anode separator, and an anode channel is formed between the anode separator 113 and the membrane electrode assembly of the UEA 112 through which a hydrogen-containing fuel gas flows. The separator 113 on the rear side of the UEA 112 is, for example, a cathode separator, and a cathode channel is formed between the cathode separator 113 and the membrane electrode assembly of the UEA 112 through which an oxygen-containing oxidizing gas flows.

[0016] The UEA 112 comprises a membrane electrode assembly (MEA) and a resin frame supporting the MEA. The MEA includes an electrolyte membrane, an anode electrode provided on the front surface of the electrolyte membrane, and a cathode electrode provided on the rear surface of the electrolyte membrane. The electrolyte membrane is, for example, a solid polymer electrolyte membrane. The anode electrode has an electrode catalyst layer formed on the front surface of the electrolyte membrane, which serves as the reaction field for the electrode reaction, and a gas diffusion layer provided on the front surface of the electrode catalyst layer, which diffuses and supplies fuel gas. The cathode electrode has an electrode catalyst layer formed on the rear surface of the electrolyte membrane, which serves as the reaction field for the electrode reaction, and a gas diffusion layer provided on the rear surface of the electrode catalyst layer, which diffuses and supplies oxidizing gas.

[0017] At the anode electrode, fuel gas (hydrogen) supplied via the anode channel and gas diffusion layer is ionized by the action of a catalyst and moves to the cathode electrode side through the electrolyte membrane. The electrons generated at this time pass through an external circuit and are extracted as electrical energy. At the cathode electrode, oxidizing gas (oxygen) supplied via the cathode channel and gas diffusion layer reacts with hydrogen ions introduced from the anode electrode and electrons that have moved from the anode electrode to produce water. The generated water provides appropriate humidity to the electrolyte membrane, and excess water is discharged to the outside of the UEA112.

[0018] The front end plate 120 has through holes 121 to 126 that penetrate the end plate 120 in the front-to-back direction. Through holes 121 to 123 are positioned vertically offset near the right end of the end plate 120, and through holes 124 to 126 are positioned vertically offset near the left end of the end plate 120. The rear end plate 120 does not have through holes 121 to 126, and the rear surface of the fuel cell stack 100 is closed. Fuel gas is supplied to the inside of the cell stack 110 through through hole 121, oxidizer gas is supplied through through hole 124, and cooling medium is supplied through through hole 125. From the cell stack 110, the cooling medium is discharged to the outside of the fuel cell stack 100 through through hole 122, oxidizer exhaust gas through through hole 123, and fuel exhaust gas through through hole 126.

[0019] As shown in Figure 2, the cell laminate 110 is supported from the inner wall of the case 130 via a plurality of support members 140, which are made of, for example, a resin material. The support members 140 are provided, for example, between the left and right ends of the upper wall 131 and the bottom wall 132 and the top and bottom surfaces of the cell laminate 110, and between the vertical ends of the left wall 133 and the right wall 134 and the left and right surfaces of the cell laminate 110, and each extends in the front-rear direction. Alternatively, or in addition to such support members 140, support members extending in the front-rear direction may be provided between the left and right central portions of the upper wall 131 and the bottom wall 132 and the top and bottom surfaces of the cell laminate 110, and between the vertical central portions of the left wall 133 and the right wall 134 and the left and right surfaces of the cell laminate 110.

[0020] Incidentally, small amounts of fuel gas may leak from the cell stack 110 of the fuel cell stack 100, for example, from the stacking surface of the power generation cell 111. The leaked fuel gas accumulates in the internal spaces SP1 and SP2 of the case 130, so it is necessary to discharge the fuel gas accumulated in the internal spaces SP1 and SP2 to the outside. In this embodiment, the fuel gas in the internal spaces SP1 and SP2 is discharged to the outside of the case 130 by ventilating the internal spaces SP1 and SP2 via the ventilation device 1. The configuration of the ventilation device 1 will be described below.

[0021] As shown in Figure 1, the ventilation device 1 has a ventilation unit 200 that is attached to the case 130 from the outside. The ventilation unit 200 is attached to the left wall 133 of the case 130, and also to the right wall 134 of the case 130, although this is not shown in the figure. Furthermore, if case 130A is provided above case 130, a ventilation unit 200 is also attached to the left wall of case 130A, as shown by the dashed line in Figure 1. In other words, a total of three ventilation units 200 are attached to cases 130 and 130A as an example. The configurations of the multiple ventilation units 200 are identical to each other, and the configurations of the mounting parts 150 for the ventilation units 200 provided on case 130 are also identical to each other. The configurations of the mounting parts 150 and the ventilation units 200 provided on the left wall 133 of case 130 will be described below.

[0022] Figure 3 is a perspective view (viewed from the left front) showing the configuration of the mounting portion 150 of the ventilation unit 200 provided on the left wall 133 of the case 130. As shown in Figure 3, the left wall 133 of the case 130 is provided with a substantially rectangular frame portion 151 that bulges to the left from the surface (left end face) 133a of the left wall 133. More specifically, the frame portion 151 bulges from the left end face 133a via a substantially arc-shaped side wall 151a (see Figure 6). Inside the frame portion 151, there is an opening 152 (referred to as the case opening) that penetrates the left wall 133 in the left-right direction. The left end face of the frame portion 151 constitutes a flat flange surface 153 that extends in the vertical and front-rear directions.

[0023] Screw holes 135 for fixing the ventilation unit 200 are provided at the four corners of the flange surface 153, and a roughly arc-shaped fixing area AR1 (double-dotted line) is formed around the screw holes 135. Figure 4 is a front view (viewed from the left) of the case opening 152. As shown in Figure 4, the case opening 152 has a roughly rectangular reference opening 152a shown by the double-dotted line, and protruding portions 152b that protrude upward, downward, forward, and backward from the reference opening 152a. The protruding portions 152b extend between adjacent pairs of fixing areas AR1. That is, they extend between the upper front-rear pair of fixing areas AR1, between the lower front-rear pair of fixing areas AR1, between the front upper-upper pair of fixing areas AR1, and between the rear upper-upper pair of fixing areas AR1. The ends of the protruding portion 152b (for example, both ends in the front-rear direction of the upper protruding portion 152b) are formed in a substantially arc shape so as not to interfere with the fixed region AR1.

[0024] The mounting area AR3 (dotted line) required for mounting the ventilation unit 200 is defined by a roughly rectangular imaginary line L1 that encloses the four fixed areas AR1. The case opening 152 has a protruding portion 152b that extends outward from the reference opening 152a, but the end of the protruding portion 152b in the protruding direction (for example, the upper end of the upper protruding portion 152b) extends to the vicinity of the imaginary line L1. This maximizes the area of ​​the case opening 152 within the roughly rectangular mounting area AR3.

[0025] Figure 5 is a front view (viewed from the left) showing the ventilation unit 200 attached to the case 130, and corresponds to a front view showing the main components of the fuel cell ventilation device 1 according to an embodiment of the present invention. Figure 6 is a cross-sectional view along the line VI-VI in Figure 5, and Figure 7 is a cross-sectional view along the line VII-VII in Figure 5. As shown in Figures 3, 6, and 7, the left wall 133 of the case 130 is provided with a plurality (3) of ribs 154 at equal intervals in the front-rear direction on the right side of the frame portion 151. The ribs 154 extend in the vertical direction, and both of their vertical ends are joined to the right end face 151b of the frame portion 151. The right end face 154a of the rib 154 is located on the same plane as the inner wall surface of the left wall 133, that is, the right end face 133b.

[0026] As shown in Figures 5 to 7, the ventilation unit 200 includes a substantially rectangular frame-shaped retaining member 2, a substantially rectangular plate-shaped filter 3 attached to the right side of the retaining member 2, and a substantially rectangular plate-shaped cover 4 positioned to the left of the retaining member 2 and supported by the retaining member 2. The retaining member 2 and the cover 4 are made of resin and formed by resin molding. The filter 3 is made of a material that allows gases such as fuel gas and air to pass through, but prevents foreign matter such as dust from passing through.

[0027] Figure 8 is a perspective view showing the main components of the ventilation unit 200 as a single unit. The configuration of the ventilation unit 200 as a single unit will also be explained using the same directions as those shown in Figures 5 to 7. As shown in Figures 5 and 8, the holding member 2 has a substantially flat base portion 20 and a wall portion 21 projecting to the left from the left surface 20a of the base portion 20. The base portion 20 is substantially rectangular in shape, and the external shape of the base portion 20 in a side view (shape viewed from the left) is the same as or nearly the same as the external shape of the frame portion 151 of the case 130. On the left surface 20a of the base portion 20, seating surfaces 20b of substantially arc-shaped regions AR2 are formed at the four corners. Region AR2 is a fixing area required to fix the holding member 2 to the frame portion 151 of the case 130.

[0028] A roughly circular through-hole 23 is opened in the center of the fixed area AR2. When the retaining member 2 is attached, a bolt 24 is inserted through the through-hole 23 from the left. The bolt 24 is screwed into the threaded hole 135 (Figure 3) of the frame portion 151. As a result, the retaining member 2 is fixed to the frame portion 151 with the right flange surface 2a (Figure 7) of the retaining member 2 in contact with the left flange surface 153 of the case 130. As shown in Figures 6 and 7, the base portion 20 is provided with an opening 22 (referred to as a filter opening) that penetrates the base portion 20 in the left-right direction, corresponding to the case opening 152 of the frame portion 151 of the case 130.

[0029] As shown in Figure 5, the filter opening 22 (dotted line) has almost the same shape as the case opening 152 (Figure 4). However, unlike the case opening 152, the filter opening 22 is provided in two halves, front to back, separated by a base portion 20 (referred to as the central base portion 27) in the center in the front-to-back direction. The central base portion 27 extends vertically while maintaining a constant length (width) in the front-to-back direction. As shown in Figures 6 and 7, the edge of the filter opening 22 is located slightly inward (towards the center of the filter opening 22) than the edge of the case opening 152. Note that the edge of the filter opening 22 and the edge of the case opening 152 may be in the same position in the front-to-back and vertical directions.

[0030] As shown in Figure 5, the filter opening 22, like the case opening 152, has a protruding portion 22a that extends outward (forward, backward, upward, and downward) from the substantially rectangular area inside the fixed area AR2. The protruding portion 22a extends between the upper front and rear pair of fixed areas AR2, between the lower front and rear pair of fixed areas AR2, between the front upper and lower pair of fixed areas AR2, and between the rear upper and lower pair of fixed areas AR2.

[0031] The wall portion 21 has a shape substantially similar to the edge of the case opening 152 and is provided on the outside of the filter opening 22 so as to surround the filter opening 22. The wall portion 21 extends along the upper edge, lower edge, left edge, and right edge of the base portion 20, except for the four corners of the holding member 2. The corners of the wall portion 21 are formed in a substantially arc shape (concave shape) along the fixed area AR2. The width W of the wall portion 21 is constant around its entire circumference.

[0032] Figure 9 shows the rear view of the ventilation unit 200 as seen from the right. As shown in Figures 6, 7, and 9, a groove 25 of predetermined depth, with substantially the same shape as the wall 21 and located substantially at the same position as the wall 21, is provided on the right side (flange surface 2a) of the base portion 20, extending around the entire circumference of the base portion 20. A sealing material 26 made of an elastic rubber material or the like is fitted into the groove 25, and the mounting surface (flange surface 2a) of the retaining member 2 is sealed via the sealing material 26. The groove 25 for attaching the sealing material may be provided on the flange surface 153 of the frame portion 151 instead of the retaining member 2. The groove for attaching the sealing material may also be provided on both the flange surface 2a and the flange surface 153.

[0033] As shown in Figures 6 and 8, notches 25a extend from the front and rear ends of the groove 25 to the front and rear end surfaces of the base 20. A tab 26a, which is integrally provided with the sealant 26 at the end of the sealant 26, is inserted into the notch 25a, as shown by the dotted line in Figure 5, and the presence or absence of the sealant 26 can be confirmed through the tab 26a. In other words, the tab 26a functions as a visible tab to prevent forgetting to assemble the sealant 26.

[0034] As shown in Figures 6 and 7, a recess 28 of a predetermined depth is provided on the inner edge of the flange surface 2a of the retaining member 2, extending around the entire circumference of the base portion 20. The outer edge of the filter 3 is fitted into the recess 28, and the filter 3 is further joined to the retaining member 2 by welding or the like. When the retaining member 2 is installed, the filter 3 is sandwiched between the retaining member 2 and the frame portion 151. A recess for fitting the filter 3 may be provided on the flange surface 153 of the frame portion 151. As shown in Figure 9, the filter 3 is formed in a shape similar to the filter opening 22, and slightly larger than the filter opening 22, so that the entire filter opening 22 is covered by the filter 3. The filter 3, like the filter opening 22, also has a protruding portion that extends between a pair of fixed regions AR2 (Figure 5).

[0035] As shown in Figures 5 and 8, the cover 4 has a shape similar to the wall portion 21 of the retaining member 2, and is positioned inside the wall portion 21 with a predetermined gap between it and the wall portion 21. Therefore, a gap CL of a predetermined width exists around the entire circumference between the cover 4 and the wall portion 21. Figure 10 is a perspective view of the cover 4 as seen from the front side (left side). As shown in Figure 10, the cover 4 is constructed in a substantially flat shape overall.

[0036] Multiple substantially arc-shaped recesses 41 of predetermined depth are provided at equal intervals in the circumferential direction on the edge of the surface (left side) 4a of the cover 4. Specifically, recesses 41 are provided at the front end, rear end, upper end, and lower end of the cover 4, respectively. The recesses 41 at the upper end and rear end are provided in pairs, one in front of and one behind the midpoint of the cover 4 in the front-rear direction. Through holes 42 are opened in the center of the multiple recesses 41. An elongated slit hole 43 is opened in the midpoint of the cover 4 in the front-rear direction.

[0037] As shown in Figures 5 and 6, on the left side 20a of the base portion 20 of the holding member 2, a plurality of protrusions 29 are provided in the area inside the wall portion 21, more specifically at the edge of the filter opening 22, corresponding to the through hole 42 of the cover 4. The protrusions 29 project to the left from the base portion 20, and their height (amount of projection to the left) is the same as or slightly lower than the height of the wall portion 21.

[0038] As shown in the detailed view of section A in Figure 6, the projection 29 has a roughly cylindrical large-diameter portion 291 that protrudes to the left from the left surface of the base portion 20, a roughly cylindrical small-diameter portion 292 that protrudes to the left from the center of the left end surface (tip surface) 291a of the large-diameter portion 291, and an arc-shaped portion 293 that protrudes to the left in a roughly arc shape from the left end (tip) of the small-diameter portion 292. The diameter of the small-diameter portion 292 is smaller than the diameters of the large-diameter portion 291 and the arc-shaped portion 293. The diameter of the through hole 42 in the cover 4 is smaller than the diameters of the large-diameter portion 291 and the arc-shaped portion 293 of the projection 29, and is equal to or approximately equal to the diameter of the small-diameter portion 292. The length of the small-diameter portion 292 in the left-right direction is the same as or approximately the same as the plate thickness of the cover 4.

[0039] The projection 29 is fitted into the through hole 42 of the cover 4. More specifically, the arc portion 293 is elastically deformed as it passes through the through hole 42, and the through hole 42 is fitted into the outer circumferential surface of the small diameter portion 292. This restricts the front-rear and up-down position of the cover 4 relative to the retaining member 2. In addition, the right side of the cover 4 abuts against the left end surface 291a of the large diameter portion 291, thereby restricting the left-right position of the cover 4 relative to the retaining member 2. In other words, the cover 4 is positioned in the front-rear, left-right, and up-down directions by the fitting of the projection 29 into the through hole 42. After being fitted into the through hole 42, the projection 29 is joined to the cover 4, for example, by welding.

[0040] When the cover 4 is attached to the projection 29, as shown in Figure 7, a gap CL is provided between the base portion 20 of the holding member 2 and the cover 4, and between the wall portion 21 and the cover 4, except for the projection 29, and extends around the entire circumference of the peripheral edge of the cover 4. Therefore, with the surface (left side) of the filter 3 covered by the cover 4, air (airflow) can flow to the filter 3 from the left side of the cover 4 through the gap CL and the opening 22.

[0041] As shown in Figure 6, a base portion 20, or central base portion 27 (Figure 5), is provided behind (to the right of) the slit hole 43 of the cover 4. The width (length in the front-to-back direction) of the central base portion 27 is wider than the width of the slit hole 43. This prevents the filter 3 from being exposed through the slit hole 43. A recess 27a is provided on the surface (left surface) of the central base portion 27 facing the slit hole 43. The recess 27a extends vertically across the entire area of ​​the slit hole 43. The width of the recess 27a is wider than the width of the slit hole 43.

[0042] As shown in Figure 7, the periphery of the filter 3 is covered by the base portion 20 of the retaining member 2, and a cover 4 is positioned inside the wall portion 21, opposite the base portion 20. Therefore, the filter 3 is not exposed to the outside through the gap CL, and it is possible to prevent raindrops and foreign objects from colliding with the filter 3 through the gap CL when the vehicle is in motion. It is also possible to prevent washing water from colliding with the filter 3 when the vehicle is high-pressure washed. However, in some areas, the filter 3 may be exposed to the outside. This point will be explained below.

[0043] Figure 11 is a rear view of the cover 4, seen from the back (right side). As shown in Figure 11, the outer edge of the cover 4 has a shape similar to the wall portion 21 (dash-dot line) such that a constant gap CL is provided around the entire circumference between the cover 4 and the wall portion 21. In particular, the corners of the cover 4 are configured to be approximately concave in shape, corresponding to the wall portion 21. More specifically, the corners have an arc portion 451 (region C1) connected to the upper and lower edges of the cover 4, an arc portion 452 (region C2) connected to the left and right edges, and an arc portion 453 (region C3) connecting the arc portion 451 and the arc portion 452.

[0044] The arc portions 451 and 452 are configured in a convex shape, and the arc portion 453 is configured in a concave shape. In this way, the corner portion of the cover 4 is formed by a plurality of arc portions 451 to 453 being connected in series. In particular, since the curvature of the arc portion 453 is different from that of the arc portions 451 and 452, the shape of the edge of the cover 4 becomes discontinuous at the arc portion 453. For this reason, when the gap CL is viewed obliquely from the outside (left side) of the cover 4, depending on the direction of viewing the cover 4, the filter 3 may be exposed. Considering this point, in the present embodiment, a protruding portion 46 protruding to the right is provided on the back surface of the cover 4 so as to prevent the filter 3 from being exposed.

[0045] FIG. 12 is a cross-sectional view taken along the line XII-XII of FIG. 11. FIG. 12 also shows the components (holding member 2, filter 3, etc.) around the cover 4. As shown in FIGS. 10 and 11, the protruding portion 46 is provided over the entire area of the arc portion 453. As shown in FIG. 12, the protruding portion 46 protrudes to the right by a predetermined length. Thereby, it is possible to reliably prevent the filter 3 (particularly the arc portion 453) from being exposed to the outside through the gap CL.

[0046] The main operation of the ventilation device 1 of the fuel cell configured as described above will be described. In the state where the ventilation unit 200 is attached to the case 130, as shown in FIG. 7, a gap (void) CL is provided over the entire circumference of the peripheral edge of the cover 4 between the holding member 2 and the cover 4, excluding the protruding portion 29 (FIG. 6). When the vehicle is running, as shown by the arrow A in FIG. 7, the running wind is taken into the internal space SP1 of the case 130 through the gap CL, the filter opening 22 of the holding member 2, the filter 3, and the case opening 152 of the left wall 133. The running wind is taken into the internal space SP1 not only through the gap CL but also through the slit hole 43 at the center of the cover 4 shown in FIG. 5.

[0047] On the other hand, the fuel gas leaked from the cell laminate 110 into the internal space SP1 is discharged to the outside of the case 130 through the case opening 152 of the left wall 133, the filter 3, the filter opening 22 of the holding member 2, and the gap CL as indicated by the arrow B in FIG. 7. Thereby, the internal space SP1 of the case 130 can be ventilated. In the present embodiment, since the gap CL through which air and fuel gas pass is provided over the entire circumference of the peripheral edge of the cover 4, the flow path area of air and fuel gas in the ventilation unit 200 increases.

[0048] Furthermore, the filter opening 22 has a protruding portion 22a that protrudes between a pair of fixing regions AR2 (FIG. 5) for attaching the ventilation unit provided on the holding member 2. Therefore, the area of the filter opening 22 within the attachment region AR3 (FIG. 4) of the ventilation unit 200, which surrounds the outer edge portion of the ventilation unit 200 with a plurality of straight lines, can be maximized. As a result, the flow rate of air taken into the internal space SP1 and the flow rate of fuel gas discharged from the internal space SP1 can be increased, and the internal space SP1 can be sufficiently ventilated. It is efficient because the area of the filter opening 22 can be increased without increasing the attachment region AR3.

[0049] The case opening 152 is provided in a frame portion 151 that bulges leftward from the left wall 133 of the case 130, and a rib 154 is provided on the right end surface 151b of the frame portion 151. Therefore, the strength of the frame portion 151 of the case 130 can be improved. In addition, since the rib 154 is provided on the outside (right side) of the frame portion 151, the inner space of the frame portion 151 is not divided or blocked by the rib 154, and a sufficient area of the case opening 152 corresponding to the filter opening 22 can be ensured.

[0050] The surface (left side) of the filter 3 is covered by the cover 4, except for the area where the slit holes 43 are provided. On the other hand, in the area where the slit holes 43 are provided, the surface of the filter 3 is covered by the central base portion 27 of the retaining member 2, as shown in Figure 6. Furthermore, the peripheral edge (arc portion 453) of the cover 4 is provided with a projection 46 that protrudes toward the filter 3. This prevents raindrops and foreign objects from colliding with the filter 3 when the vehicle is in motion. It also prevents cleaning water from colliding with the filter 3 when the vehicle is being high-pressure washed. Thus, the filter 3 is protected, and the durability of the ventilation unit 10 is improved. When cleaning or replacing the filter 3, the bolts 24 (Figure 5) are loosened and the ventilation unit 200 is removed from the case 130. This makes cleaning and replacing the filter 3 easy.

[0051] This embodiment provides the following effects: (1) The ventilation unit 200 is attached to the case 130 so as to cover a case opening 152 that connects the internal space SP1 of the fuel cell case 130 to the external space (Figure 6). The ventilation unit 200 includes a filter 3 positioned facing the flange surface 153 of the case 130 so as to cover the case opening 152, a frame-shaped holding member 2 attached to the case 130 while holding the peripheral edge of the filter 3, and a filter opening 22 having substantially the same shape as the case opening 152, and a cover 4 attached to the holding member 2 so as to cover the inside of the peripheral edge of the filter 3 (Figure 6). The holding member 2 is provided along the peripheral edge of the holding member 2 and has a plurality of fixing regions AR2 for fixing the holding member 2 to the case 130 (Figure 5). The filter opening 22 extends into the region between a pair of fixing regions AR2 among the plurality of fixing regions AR2 (Figure 5). In other words, the opening 22 has a protruding portion 22a that extends between the pair of fixed regions AR2.

[0052] By providing a protruding portion 22a to the filter opening 22 in this way, the area of ​​the filter opening 22 within the substantially rectangular mounting area AR3 defined by the multiple fixed areas AR2, i.e., the ratio of the area of ​​the filter opening 22 to the area occupied by the ventilation unit 200, can be maximized. This allows the ventilation unit 200 to be made smaller. Furthermore, the number of ventilation units 200 can be reduced, thereby reducing the cost of the ventilation device 1.

[0053] (2) The peripheral edge of the retaining member 2 has a left surface 20a facing the cover 4 and a projection 29 that supports the cover 4 in a state spaced apart from the left surface 20a of the retaining member 2 (Figures 5 and 6). This allows a gap CL to be provided around the entire circumference of the cover 4 between the retaining member 2 and the peripheral edge of the cover 4. As a result, the flow path area of ​​the ventilation unit 200 when outside air is taken into the internal space SP1 of the case 130 is increased, and a large flow rate of outside air can be taken into the internal space SP1. As a result, the internal space SP1 can be sufficiently ventilated. In addition, since the front surface of the filter 3 is covered by the cover 4, it is possible to prevent raindrops and foreign objects from colliding with the filter 3 when the vehicle is running, and to prevent washing water from colliding with the filter 3 when the vehicle is high-pressure washed, thereby suppressing damage to the filter 3.

[0054] (3) The peripheral edge of the cover 4 has arc portions 451 to 453 that curve along the fixed area AR2 (Figure 11). The arc portion 453 has a projection 46 that protrudes toward the left surface 20a of the retaining member 2 (Figure 12). As a result, even if the peripheral edge of the cover 4 is provided with arc portions 453 as discontinuous portions with different curvatures, the filter 3 in the vicinity of the arc portion 453 will not be exposed to the outside, and washing water will not collide with the filter 3 during high-pressure washing.

[0055] (4) The fuel cell ventilation device 1 comprises a case 130 that houses a cell stack 110 made up of a plurality of power generation cells 111 stacked on top of each other, a ventilation unit 200 attached to the case 130 so as to cover a case opening 152 that connects the internal space SP1 of the case 130 to the external space, and bolts 24 that fix the ventilation unit 200 to the case 130 (Figures 1 and 5). The ventilation unit 200 has a filter 3 positioned facing the flange surface 153 of the case 130 so as to cover the case opening 152, a frame-shaped holding member 2 attached to the case 130 while holding the peripheral edge of the filter 3 and having a filter opening 22 that is substantially the same shape as the case opening 152, and a cover 4 attached to the holding member 2 so as to cover the inside of the peripheral edge of the filter 3 (Figure 6). The holding member 2 has a plurality of fixing regions AR2 provided along the peripheral edge of the holding member 2 where the bolts 24 are arranged (Figure 5). The filter opening 22 extends into the region between a pair of fixed regions AR2 among a plurality of fixed regions AR2 (Figure 5). This allows fuel gas leaking from the stacking surface of the power generation cells 111 of the cell stack 110 to be discharged to the outside via the ventilation unit 200. Since the ventilation unit 200 can be made compact, it can be easily attached to the fuel cell case 130.

[0056] (5) The case opening 152 is provided on the side of the case 130 (Figure 1). The case opening 152 may be provided on the top surface of the case 130 instead of the side surface, or on both the side surface and the top surface of the case 130. That is, the case opening 152 may be provided on at least one of the side surface and the top surface of the case 130. This makes it easy to discharge the fuel gas in the internal space SP1 to the external space of the case 130.

[0057] (6) The case 130 has a frame portion 151 that forms the case opening 152, and a rib 154 provided on the end of the frame portion 151 on the SP1 side of the internal space (right end face 151b) so as to cross the case opening 152 (Figure 3). This makes it possible to increase the strength of the frame portion 151 while ensuring a sufficient area of ​​the case opening 152.

[0058] The above embodiment can be modified into various forms. Several modifications are described below. In the above embodiment (Figure 1), the ventilation unit 200 is attached to the fuel cell case 130 (fuel cell case), but the ventilation unit may be attached to another housing that requires ventilation. In the above embodiment (Figure 5), the filter opening (ventilation opening) is divided into two in the front-rear direction via the central base portion 27, but the ventilation opening may be a single opening or divided into three or more. That is, the configuration of the ventilation opening can be anything as long as it extends into the area between a pair of fixing portions among a plurality of fixing regions (fixing portions). In the above embodiment (Figure 5), a fixing region AR2 for fixing the holding member 2 to the case 130 is provided at the corner of the holding member 2, but the configuration of the fixing portion is not limited to that described above.

[0059] In the above embodiment (Figure 5), the ventilation unit 200 is configured in a substantially rectangular shape, but the shape of the ventilation unit is not limited to that described above. In the above embodiment (Figure 5), the filter opening 22 is provided with protruding portions 22a that extend outward from the four substantially rectangular sides, but the configuration of the protruding portions is not limited to that described above. That is, the shape of the ventilation opening can be anything as long as it is configured to be substantially the same shape as the case opening 152 while holding the peripheral edge of the filter 3. In the above embodiment (Figure 6), the peripheral edge of the holding member 2 is provided with an end face (left face 20a) facing the cover 4 and a projection 29 (cover support portion) that supports the cover 4 while spaced apart from the left face 20a, but the configuration of the cover support portion is not limited to that described above.

[0060] In the above embodiment (Figure 11), the periphery of the cover 4 is provided with arc portions 451 to 453 (curved portions) that curve along the fixing area AR2, and a projection 46 (projection portion) is provided on the arc portion 453 that protrudes toward the end face (left face 20a) of the retaining member 2. However, the configuration of the cover 4 is not limited to that described above. In the above embodiment (Figure 5), the ventilation unit 200 is fixed to the case 130 by bolts 24. However, the configuration of the fixing member is not limited to that described above. In the above embodiment (Figure 3), the left wall 133 of the case 130 is provided with a frame portion 151 that forms a case opening 152 (opening) and a rib 154 (rib portion) provided at the right end (internal space SP1 side) of the frame portion 151 so as to cross the case opening 152. However, the rib portion may be omitted.

[0061] In the above embodiment, an example of applying the ventilation device 1 to a fuel cell mounted on a vehicle was described. However, the ventilation device of the present invention can also be applied to mobile bodies other than vehicles, such as aircraft and ships, robots, and fuel cells mounted on various industrial machines.

[0062] The above description is merely an example, and the present invention is not limited by the embodiments and modifications described above, as long as the features of the present invention are not impaired. It is also possible to arbitrarily combine one or more of the above embodiments and modifications, and to combine modifications with each other.

[0063] 1 Ventilation device, 2 Holding member, 3 Filter, 4 Cover, 20a Left side, 22 Filter opening, 24 Bolt, 29 Projection, 46 Protrusion, 110 Cell stack, 111 Power generation cell, 130 Case, 151 Frame, 152 Case opening, 153 Flange surface, 154 Rib, 200 Ventilation unit, 451-453 Projections, SP1 Internal space, AR2 Fixed area

Claims

1. A ventilation unit attached to a housing so as to cover an opening that connects the internal space of the housing to the external space, comprising: a filter disposed facing the surface of the housing so as to cover the opening; a frame-shaped retaining member attached to the housing while holding the peripheral edge of the filter, the retaining member having a ventilation opening substantially the same shape as the opening; and a cover attached to the retaining member so as to cover the inside of the peripheral edge of the filter, wherein the retaining member has a plurality of fixing parts provided along the peripheral edge of the retaining member for fixing the retaining member to the housing, and the ventilation opening extends into the region between a pair of the plurality of fixing parts.

2. A ventilation unit according to claim 1, characterized in that the peripheral edge of the holding member has an end face facing the cover and a cover support portion that supports the cover in a state spaced apart from the end face.

3. The ventilation unit according to claim 2, wherein the peripheral edge of the cover has a curved portion that curves along the fixing portion, and the curved portion has a protruding portion that protrudes toward the end face of the holding member.

4. A fuel cell ventilation device comprising: a fuel cell case housing a laminate of multiple power generation cells stacked on top of each other; a ventilation unit attached to the fuel cell case so as to cover an opening that connects the internal space of the fuel cell case to the external space; and a fixing member for fixing the ventilation unit to the fuel cell case, wherein the ventilation unit comprises: a filter positioned facing the surface of the fuel cell case so as to cover the opening; a frame-shaped holding member attached to the fuel cell case while holding the peripheral edge of the filter, and having a ventilation opening substantially the same shape as the opening; and a cover attached to the holding member so as to cover the inside of the peripheral edge of the filter, wherein the holding member has a plurality of fixing parts provided along the peripheral edge of the holding member on which the fixing member is positioned, and the ventilation opening extends into the region between a pair of the plurality of fixing parts.

5. A fuel cell ventilation device according to claim 4, characterized in that the opening is provided on at least one of the side surface and the top surface of the fuel cell case.

6. A fuel cell ventilation device according to claim 4 or 5, wherein the fuel cell case comprises a frame portion that forms the opening and a rib portion provided at the end of the frame portion on the internal space side so as to traverse the opening.

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