fuel cell system

Abstract

The present invention relates to a fuel cell system. A fuel cell system (10) mounted on a vehicle (12) includes a stack housing (20) for housing a fuel cell stack (18). A rear opening (40) is formed in a rear portion (36d) of the stack housing, facing the rear of the vehicle. Single cell voltage detection terminals (60) electrically connected to electrodes of the fuel cell stack are exposed in the rear opening. A filter cover (70) configured to include a filter element (71) is provided in the rear opening 40. The filter cover has a vehicle-height-direction rib (116) extending in the vehicle-height direction.

Description

Technical Field

[0001] The present invention relates to a fuel cell system that is mounted on a vehicle in a state where a fuel cell stack is housed in a stack case. Background Art

[0002] When a fuel cell system including a fuel cell stack is mounted on a vehicle, a structure in which the fuel cell stack is housed in a stack case as described in Patent Document 1 is widely used. Figure 1 As shown, the stack casing is provided with a ventilation cover on the wall surface covering the stacking direction ends of the battery cells constituting the fuel cell stack. If hydrogen leaks from the fuel cell stack, the hydrogen is discharged to the outside of the stack casing through the ventilation cover including a filter.

[0003] Here, the fuel cell system includes a voltage control unit (VCU) that controls the voltage of the fuel cell stack. The VCU is housed in a housing, which, as shown in Patent Documents 2 and 3, is located behind the stack housing. A rear opening (referred to as a "rear window" in Patent Document 2) is formed in the rear portion of the stack housing. The front portion of the housing, housing the VCU, faces this opening.

[0004] The fuel cell stack is equipped with single-cell voltage detection terminals (also called "single-cell V-terminals") that are electrically connected to each electrode of the fuel cell stack via a wiring harness. These single-cell V-terminals are exposed through the rear opening. This allows operators to access these terminals and their surrounding areas through the rear opening to perform maintenance. This creates a work window.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-76152

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2020-82753

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 2020-29190 Summary of the Invention

[0010] Consider installing the ventilation cover described in Patent Document 1 in the rear opening described in Patent Documents 2 and 3. However, as mentioned above, the wiring harness for the V-terminals of the battery cells is exposed at the rear opening. Therefore, if, for example, the battery cell row flexes to bulge toward the rear opening, the wiring harness presses against the ventilation cover, placing a load on it. Excessive load could lead to deformation of the ventilation cover or permanent deformation of the filter.

[0011] A primary object of the present invention is to provide a fuel cell system provided with a filter cover having sufficient rigidity to protect a filter element.

[0012] According to one technical solution of the present invention, a fuel cell system is provided. The fuel cell system includes a fuel cell stack and a stack casing for accommodating the fuel cell stack, and is mounted on a vehicle. In the fuel cell system,

[0013] The fuel cell stack is composed of battery cells stacked in the vehicle width direction.

[0014] A rear opening is formed at the rear portion of the stack housing facing rearward in the forward direction of the vehicle, and a single cell voltage detection terminal electrically connected to the electrode of the battery cell is exposed at the rear opening. A filter cover including a filter element is provided at the rear opening.

[0015] The filter cover has a vehicle-height direction rib extending in the vehicle-height direction.

[0016] In the present invention, the filter cover, which covers the rear opening of the stack housing, is equipped with vehicle-height ribs extending in the vehicle-height direction. These vehicle-height ribs impart rigidity to the filter cover. Consequently, even if the wires extending from the cell voltage detection terminals exposed in the rear opening come into contact with the filter cover, permanent deformation or damage to the filter element is avoided. In other words, the filter element is adequately protected.

[0017] The above-mentioned objects, features, and advantages will be easily understood from the following description of the embodiments described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic side view of the main parts of a vehicle equipped with a fuel cell system according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic perspective view of a stack casing constituting the fuel cell system as viewed from the rear.

[0020] Figure 3 This is an exploded perspective view of the filter cover.

[0021] Figure 4 This is a schematic front view of the filter cap.

[0022] Figure 5 This is a schematic overall perspective view of a holding plate (holding member) constituting the filter cover.

[0023] Figure 6 yes Figure 4 Cross-sectional view in the direction of the arrow on line VI-VI.

[0024] Figure 7It is a schematic longitudinal sectional side view showing the vicinity of a connection portion between the stack case and the electrical device housing case.

[0025] Figure 8 This is a schematic front view of the entire sealing plate (holding frame member) of another shape. DETAILED DESCRIPTION

[0026] The fuel cell system of the present invention is described in detail below, using preferred embodiments and referring to the accompanying drawings. In the following description, "left," "right," "front," "rear," "bottom," and "top" refer to the left, right, front, rear, bottom, and top sides of a user seated in the driver's seat of a vehicle. Furthermore, the vehicle width direction is synonymous with the left-right direction, the vehicle length direction is synonymous with the front-back direction or the forward direction, and the vehicle height direction is synonymous with the up-down direction.

[0027] Figure 1 This is a schematic side view of the main parts of a fuel cell vehicle 12 (vehicle) equipped with a fuel cell system 10 according to this embodiment. A front compartment 16 is provided at the front of the fuel cell vehicle 12. The front compartment 16 is separated from the passenger compartment 15 by an instrument panel 14. A stack housing 20 housing a fuel cell stack 18 is disposed within the front compartment 16.

[0028] The front room 16 is provided with a side frame 22 and a cross member 24 constituting a vehicle body frame. The side frame 22 extends in the vehicle length direction, and the cross member 24 extends in the vehicle width direction below the side frame 22.

[0029] The fuel cell stack 18 generates electricity through an electrochemical reaction between fuel gas and oxidant gas supplied from a fuel gas supply device and an oxidant gas supply device (neither of which are shown). The fuel cell stack 18 supplies the generated electricity to a propulsion motor 26 located in the front compartment 16 and a battery (not shown).

[0030] In this case, the travel motor 26 is disposed below the fuel cell stack 18 or the stack casing 20. The travel motor 26 propels the fuel cell vehicle 12 via a transmission and wheels (not shown). The front side of the travel motor 26 is secured to the cross member 24 via a motor bracket 28a and a front support 30a. The rear side of the travel motor 26 is secured to the cross member 24 via a motor bracket 28b and a rear support 30b.

[0031] A PDU (power drive unit) 32 is provided in front of the travel motor 26 to supply appropriate power to the travel motor 26. The PDU 32 is configured as a three-phase bridge inverter, converting the power (DC power) generated by the fuel cell stack 18 into AC power and adjusting the rotational drive force of the travel motor 26 under the control of an ECU (not shown).

[0032] like Figure 2 As shown, the fuel cell stack 18 includes a plurality of battery cells 34 stacked in the vehicle width direction. In this state, the fuel cell stack 18 is housed inside the stack case 20. At this time, the electrodes of the battery cells 34 are in an upright position.

[0033] The stack housing 20 has a bottom wall 36a, a front wall 36b, and an upper wall 36c. A rear opening 40 is formed in the rear portion 36d of the stack housing 20. Furthermore, a right opening 42a and a left opening 42b are formed in the right side 36e and left side 36f of the stack housing 20 in the vehicle width direction, respectively.

[0034] At the right end of the battery cells 34 in the stacking direction (vehicle width direction), a first terminal plate and a first insulating plate (not shown) are arranged in this order toward the outside. These first terminal plate and first insulating plate are housed within the stack housing 20. Furthermore, a first end panel 44 is attached to the right side 36e of the stack housing 20. The first end panel 44 closes the right opening 42a of the stack housing 20, applying a tightening load in the stacking direction to the stack of battery cells 34.

[0035] Similarly, a second terminal plate and a second insulating plate (not shown) are sequentially arranged outward at the left end of the stacking direction of the battery cells 34. The second terminal plate and the second insulating plate are housed in the stack case 20. Furthermore, an auxiliary equipment case 46 is attached to the left side 36f of the stack case 20.

[0036] The auxiliary equipment housing 46 includes a concave first housing member 48 screwed to the stack housing 20 and a concave second housing member 50 joined to the first housing member 48. These members house auxiliary equipment such as piping, injectors, hydrogen pumps, and valves (hydrogen supply devices: components of the fuel cell system).

[0037] The first housing member 48 includes a wall portion 54 that closes the left opening 42b at the left end of the stack housing 20 in the stacking direction. This wall portion 54 functions as a second end panel that applies a tightening load in the stacking direction to the stack of battery cells 34. The first end panel 44 and the wall portion 54 are attached to the stack housing 20 by fastening bolts 58, with a sealing member 56 interposed between them.

[0038] The electrodes (anode and cathode) at both ends of the stacked battery cells 34 are electrically connected to the first and second terminal plates. Portions of the two terminal plates protrude externally from an opening in the upper wall 36c of the stack housing 20 and are electrically connected to the VCU 150 via contactors (not shown). Meanwhile, the cell V-terminals (cell voltage detection terminals) 60 are electrically connected to each battery cell 34. In particular, although not shown, connection portions are provided on the outer periphery of the separators in each battery cell 34, and the cell V-terminals 60 are electrically connected to these connection portions.

[0039] The plurality of single cell V terminals 60 are detachably mounted on the rear portion of the fuel cell stack 18 facing the rear opening 40 and are exposed to the rear opening 40. Figure 7 As shown, a wiring harness 62 (a bundle of wires) that transmits the detected cell voltages to a cell voltage control unit 61 extends from the rear of the cell V-terminal 60. The cell voltage control unit 61 integrates and processes the voltages detected by the cell V-terminal 60 internally before transmitting the integrated voltages to the control system of the fuel cell stack 18.

[0040] like Figure 3 as well as Figure 4 As shown in detail in FIG, a filter cover 70 is provided at the rear opening 40. In this embodiment, the filter cover 70 includes a filter 71, a holding plate 72 (holding member), and a sealing plate 74 (holding frame member).

[0041] The filter element 71 includes an inner protective mesh 76, a filter membrane 78, and an outer protective mesh 80. The inner protective mesh 76, filter membrane 78, retaining plate 72, outer protective mesh 80, and sealing plate 74 are arranged in this order, starting from the side closest to the stack housing 20, to form the filter cover 70.

[0042] The inner and outer protective grids 76 and 80 are formed from mesh plates with relatively large mesh openings in a grid or circular pattern. In contrast, the filter membrane 78 is a plate with finer pores than those of the inner and outer protective grids 76 and 80. Therefore, the filter membrane 78 collects foreign matter that is not caught by the outer protective grid 80. The inner and outer protective grids 76 and 80 protect the filter membrane 78, which is held between the two grids 76 and 80.

[0043] For example, the inner protective mesh 76 is made of a fiber-reinforced resin material obtained by impregnating glass fibers with resin. On the other hand, the outer protective mesh 80 is made of a metal such as an aluminum alloy.

[0044] In addition, for example, the retaining plate 72 is made of a fiber-reinforced resin material made by impregnating glass fiber with resin, similarly to the inner protective grid 76. Figure 5 As shown, the retaining plate 72 has an outer edge frame 90 and a left lower stepped protrusion 92, a left upper stepped protrusion 94, and a right stepped protrusion 96 that slightly protrude toward the outer protection grid 80 from the inner side surrounded by the outer edge frame 90. Due to the steps between the outer edge frame 90 and these three stepped protrusions 92, 94, and 96, an inner step 98 is formed on the side of the retaining plate 72 facing the stack housing 20 (see FIG. Figure 7 ).

[0045] On the other hand, on the side of the retaining plate 72 facing the outer protective grid 80, a frame-like step 100 is formed by the step between the outer edge frame 90 and the three stepped protrusions 92, 94, and 96. Furthermore, a horizontal step 102 extending in the vehicle width direction is formed between the lower left stepped protrusion 92 and the upper left stepped protrusion 94. Furthermore, a vertical step 104 is formed between the lower left stepped protrusion 92 and the upper left stepped protrusion 94 and the right stepped protrusion 96.

[0046] On the lower left stepped convex portion 92, a plurality of vents 106Ld and 106Lm are formed, for example, in two rows arranged in the vertical direction. Furthermore, on the upper left stepped convex portion 94, a plurality of vents 106Lu are formed in the same number of columns as the vents 106Ld and 106Lm. For example, the number of rows of vents 106Lu is one. Furthermore, on the right stepped convex portion 96, vents 106Rd and Ru are formed in two rows arranged in the vertical direction. Vents 106Ld, 106Lm, 106Lu, 106Rd, and 106Ru are, for example, in the shape of vertically elongated rectangles.

[0047] Vent 106Rd and vent 106Ru are separated by a distance approximately equal to the vehicle height dimension of vent 106Lm. This separation creates a closed wall 108 between vent 106Rd and vent 106Ru. Closed wall 108 is, of course, a portion of the wall surface of right stepped convex portion 96. The cell voltage control unit 61 faces the front surface of closed wall 108.

[0048] Furthermore, the inner protective grid 76, the filter membrane 78, and the outer protective grid 80 are each divided into a plurality of parts corresponding to the positions of the grids of the retaining plate 72. That is, each partition of the inner protective grid 76, the filter membrane 78, and the outer protective grid 80 is formed to cover the vents 106Ld, 106Lm, 106Lu, 106Rd, and 106Ru individually or to cover them across two rows.

[0049] like Figure 4As shown in detail in the figure, the sealing plate 74 has a generally rectangular outer frame portion 114 having four sides: a left longitudinal side 112L, a right longitudinal side 112R, a lower side 112D, and an upper side 112U. The left and right longitudinal sides 112L and 112R extend in the vehicle height direction, while the lower side 112D and the upper side 112U extend in the vehicle width direction. The left longitudinal side 112L is connected to the left ends of the lower side 112D and the upper side 112U. Meanwhile, the right longitudinal side 112R is connected to the right ends of the lower side 112D and the upper side 112U. Furthermore, a vehicle height rib 116 is provided approximately midway between the lower side 112D and the upper side 112U in the vehicle width direction. The vehicle height rib 116 extends in the vehicle height direction and connects to the lower side 112D and the upper side 112U. That is, the left longitudinal side 112L, the right longitudinal side 112R, and the vehicle-height direction rib 116 are parallel to each other.

[0050] Additionally, a vehicle-width rib 118 (cross rib) extending in the vehicle width direction is formed approximately midway between the left longitudinal side 112L and the vehicle-width rib 116. The vehicle-width rib 118 intersects the vehicle-width rib 116 at approximately right angles. The lower side 112D, upper side 112U, and vehicle-width rib 118 are parallel to each other. Furthermore, the vehicle-width rib 116 and vehicle-width rib 118 define three ventilation openings 120 on the inner side of the outer frame 114.

[0051] Preferred examples of the material of the sealing plate 74 having such a structure include metals such as aluminum alloys similar to those used for the outer protective mesh 80 .

[0052] like Figure 6 as well as Figure 7 As shown, an internal step 98 is formed on the rear surface side of the retaining plate 72. The filter membrane 78 and the inner protective grid 76 are accommodated in the internal step 98. In addition, the sealing plate 74 is connected to the rear portion 36d of the stack housing 20 by fixing bolts 122, thereby covering the rear opening 40 with the filter cover 70.

[0053] At this time, if Figure 4 as well as Figure 6 As shown, the inner periphery of the outer frame portion 114 of the sealing plate 74 and the frame-shaped step 100 of the outer periphery of the holding plate 72 (see Figure 5 ) are engaged. Furthermore, the vehicle-width ribs 118 engage with the concave horizontal steps 102 of the retaining plate 72, and the vehicle-height ribs 116 engage with the concave vertical steps 104 of the retaining plate 72. Thus, each component from the inner protective grid 76 to the outer protective grid 80 is supported by the vehicle-width ribs 118 and the vehicle-height ribs 116. As a result, the rigidity of the filter cover 70 is ensured.

[0054] Furthermore, in the present embodiment, in a state where the filter cover 70 is attached to the rear opening 40 as described above, the wire harness 62 abuts against the inner protection mesh 76 constituting the filter cover 70 .

[0055] Also, such as Figure 2 as well as Figure 7 As shown, a VCU housing 152 (electrical equipment storage housing) that houses a VCU 150 serving as an electrical device is connected to the rear portion 36d of the stack housing 20. Four mounting portions 154 are provided on the front wall of the VCU housing 152, facing the stack housing 20, so as to protrude toward the stack housing 20. Furthermore, through-holes 158 are formed from the rear wall of the VCU housing 152 to the front end surfaces of the mounting portions 154, through which mounting bolts 156 pass. The mounting bolts 156 passing through the through-holes 158 are threadedly engaged with bolt holes (not shown) formed in the rear portion 36d of the stack housing 20, thereby retaining the filter cover 70 in the stack housing 20 and connecting the VCU housing 152 to the stack housing 20.

[0056] At this time, a gap is formed between the rear portion 36d of the stack housing 20 (or the filter cover 70) and the front wall of the VCU housing 152 by an amount equivalent to the protruding length of the assembly portion 154. Figure 7 As shown, ventilation ports 160 are formed between adjacent mounting portions 154 .

[0057] The fuel cell system 10 of the present embodiment is basically configured as described above, and its operations and effects will be described below.

[0058] When the filter cover 70 is mounted on the rear portion 36d of the stack housing 20, the inner protective grid 76, the retaining plate 72 holding the filter membrane 78, the outer protective grid 80, and the sealing plate 74 are overlapped, starting from the side closest to the stack housing 20. Furthermore, the sealing plate 74 is connected to the rear portion 36d by means of fixing bolts 122. Through this connection, the filter cover 70 including the filter element 71 is mounted on the rear portion 36d of the stack housing 20 so as to cover the rear opening 40. With this mounting, as described above, the outer frame portion 114 of the sealing plate 74 engages with the frame-shaped step 100. Furthermore, the vehicle width ribs 118 engage with the horizontal step 102, and the vehicle height ribs 116 engage with the vertical step 104.

[0059] At this time, the row of battery cells 34 may bend so as to bulge toward the rear opening 40. In this case, the wire harness 62 extending from the cell V-terminal 60 abuts against the inner protective mesh 76. This compresses the filter cover 70 from the wire harness 62, placing a load on the filter membrane 78, which has the least rigidity.

[0060] In this embodiment, as described above, the rigidity of the filter cover 70 is ensured by the support provided by the vehicle-width ribs 118 and vehicle-height ribs 116 provided on the sealing plate 74. Consequently, the filter cover 70 exhibits sufficient durability. As a result, permanent deformation or damage to the filter element 71 (particularly the filter membrane 78) is prevented. Thus, by providing the vehicle-width ribs 118 and vehicle-height ribs 116 on the components that constitute the filter cover 70 (in this case, the sealing plate 74), the filter element 71, including the filter membrane 78, is protected from permanent deformation or damage.

[0061] Furthermore, the closing wall portion 108 is formed on the holding plate 72. This improves the strength of the holding plate 72, and thus the cell voltage control unit 61 adjacent to the inner side of the holding plate 72 can be well protected.

[0062] After the rear opening 40 is covered with the filter cover 70 as described above, the VCU case 152 is attached to the rear portion 36d of the stack case 20. Specifically, the assembly bolts 156 are passed through the through holes 158 and screwed into bolt holes (not shown).

[0063] exist Figure 1 When the fuel cell vehicle 12 shown is in operation, fuel gas, oxidant gas, and a coolant are supplied to the fuel cell stack 18. Fuel gas is supplied to the anode electrode of each battery cell 34, while oxidant gas is supplied to the cathode electrode of each battery cell 34. This generates electricity in each battery cell 34, which in turn applies force to the driving motor 26. As a result, the fuel cell vehicle 12 begins to travel. Furthermore, a coolant is also supplied to each battery cell 34.

[0064] Suppose that while the fuel cell vehicle 12 is driving, a foreign object S, such as a small stone, is lifted off the tire and flies toward the front chamber 16. In such a situation, the foreign object S reaches the VCU housing 152. It is clear that the filter cover 70 is protected by the VCU housing 152, which covers the filter cover 70, and is therefore protected from the large foreign object S that enters the front chamber 16.

[0065] Furthermore, if foreign matter S enters between the stack housing 20 and the VCU housing 152 through the ventilation port 160, the filter membrane 78 is protected by the outer protective mesh 80. This prevents the filter membrane 78 from being damaged, preventing it from capturing even tiny foreign matter. Furthermore, the cell voltage control unit 61 within the stack housing 20 is also protected from foreign matter S by the enclosing wall 108 covering it.

[0066] A portion of the traveling wind reaches the lower portion of the rear portion 36d of the stack casing 20. It then passes through the ventilation openings 120 of the sealing plate 74, the mesh of the outer protective mesh 80, the ventilation openings 106Ld, 106Lm, 106Lu, 106Rd, and 106Ru of the retaining plate 72, the pores of the filter membrane 78, and the mesh of the inner protective mesh 76, entering the interior of the stack casing 20 through the rear opening 40. If the traveling wind contains fine foreign matter such as sand and dust, the foreign matter is captured by the outer protective mesh 80 and the filter membrane 78. Consequently, the foreign matter is less likely to enter the stack casing 20.

[0067] The temperature of the fuel cell stack 18 within the stack casing 20 rises as each cell 34 generates electricity. Consequently, heat is applied from the fuel cell stack 18 to the traveling air entering the stack casing 20. This causes the traveling air to heat up, causing the traveling air to rise within the stack casing 20. Meanwhile, the traveling air cools the fuel cell stack 18.

[0068] When fuel gas leaks from the fuel cell stack 18 into the stack casing 20, the hydrogen in the fuel gas has a lower specific gravity than air, so it also rises within the stack casing 20 and merges with the traveling wind. The traveling wind (and hydrogen) flows from the upper portion of the rear opening 40 through the mesh of the inner protective grid 76, the pores of the filter membrane 78, the vents 106Ld, 106Lm, 106Lu, 106Rd, and 106Ru of the retaining plate 72, the mesh of the outer protective grid 80, and the vent opening 120 of the sealing plate 74, and is discharged to the exterior of the stack casing 20. The traveling wind (and hydrogen) further reaches the front chamber 16 through the ventilation port 160, from which it diffuses into the atmosphere.

[0069] When maintenance is required on the fuel cell stack 18 (particularly the single cell V-terminals 60 and the like), the operator simply loosens the assembly bolts 156 and removes the VCU housing 152 from the stack housing 20. The operator then loosens the fixing bolts 122 and detaches the filter cover 70 from the stack housing 20. This detachment exposes the rear opening 40, making it easy to perform maintenance on the single cell V-terminals 60 and the like exposed through the rear opening 40.

[0070] The present invention is not particularly limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0071] For example, Figure 8 As shown, a sealing plate 74B may also be employed in which the vehicle-width ribs 118 extend beyond the vehicle-height ribs 116 and extend to connect with the right longitudinal edge 112R. Furthermore, the cross-ribs are not limited to the vehicle-width ribs 118; any rib extending crosswise with the vehicle-height ribs 116 may be used. Furthermore, cross-ribs such as the vehicle-width ribs 118 are not necessarily required; only the vehicle-height ribs 116 may be provided.

[0072] Furthermore, the shapes of the vents 106Ld, 106Lm, 106Lu, 106Rd, and 106Ru of the holding plate 72 may be other shapes (such as circular) other than rectangular.

Claims

1. A fuel cell system comprising a fuel cell stack (18) and a stack casing (20) for accommodating the fuel cell stack, and mounted on a vehicle (12), wherein in the fuel cell system (10), The fuel cell stack is composed of a plurality of battery cells (34) stacked in a vehicle width direction. A cell voltage detection terminal electrically connected to an electrode of each of the battery cells is provided at a rear portion of each of the battery cells facing rearward in the forward direction of the vehicle. A rear opening (40) is formed at a rear portion (36d) of the stack housing facing rearward in the forward direction of the vehicle, the single cell voltage detection terminal (60) is exposed at the rear opening (40), and a filter cover (70) covering the rear opening is provided at the rear opening. The filter cover (70) includes a filter element (71) for collecting foreign matter. The filter cover has a vehicle height direction rib (116) extending in the vehicle height direction.

2. The fuel cell system according to claim 1, wherein: The filter cover has a cross-direction rib (118) extending in a direction crossing the vehicle-height direction rib.

3. The fuel cell system according to claim 2, wherein: The filter cover has a holding frame member (74) connected to the stack housing, the filter element is sandwiched between the holding frame member and the stack housing, and a ventilation opening is formed.

4. The fuel cell system according to claim 3, wherein: The vehicle-height direction rib is formed on the holding frame member.

5. The fuel cell system according to claim 3, wherein: The intersecting ribs are formed on the holding frame member.

6. The fuel cell system according to claim 4, characterized in that The intersecting ribs are formed on the holding frame member.

7. The fuel cell system according to claim 1, wherein: A lead wire (62) extending from the battery voltage detection terminal abuts against the filter.

8. The fuel cell system according to claim 1, wherein: The filter element is formed by stacking an inner protection grid (76), a filter membrane (78), and an outer protection grid (80) in this order starting from the side close to the stack housing.

9. The fuel cell system according to claim 8, characterized in that The filter cap further includes a holding member (72) that holds the filter membrane from the outer protective mesh side and is formed with vents (106Ld, 106Lm, 106Lu, 106Rd, 106Ru).

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