fuel cell system

Abstract

To suppress an electric component from being splashed with water.SOLUTION: A fuel battery system 10 contains: a fuel battery stack 12; and a reactor 35, and includes: a DC / DC converter 30 that changes an output voltage of the fuel battery stack 12; a housing 11 that houses the fuel battery stack 12 and the DC / DC converter 30, and in which a vent hole 11h is formed; and a fan 20 that is provided to the housing 11. By the driving of the fan 20, an airflow flowing between the vent hole 11h and the fan 20 is generated in an inner part of the housing 11. The fuel battery stack 12 includes a coated wall 70 that covers one part of the reactor 35 so as to prevent a flow of the airflow. The fan 20 is positioned at a downstream to a flow direction F of the airflow from the reactor 35. The coated wall 70 includes: a first wall part 71 that is positioned between the fan 20 and the reactor 35 in the flow direction F of the airflow; and a second wall part 72 that is positioned above the reactor 35 in a vertical direction Z.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a fuel cell system. [Background technology]

[0002] The fuel cell system described in Patent Document 1 includes a fuel cell, electrical components, a housing that houses the fuel cell and electrical components, and a fan. When the fan is driven, an airflow is generated inside the housing that flows between the fan and the ventilation openings in the housing. In the fuel cell system described in Patent Document 1, the airflow generated inside the housing facilitates heat exchange between the electrical components and the air. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-151722 Summary of the Invention [Problem to be solved by the invention]

[0004] Rainwater splashing on the fuel cell system or other reasons can cause water to seep into the housing from the outside through gaps between the fan blades. In this case, if the water that has seeped into the housing splashes on the electrical components, it may adversely affect the performance of the electrical components, which is undesirable. [Means for solving the problem]

[0005] A fuel cell system for solving the above problem comprises a fuel cell, a voltage conversion device including electrical components and changing the output voltage of the fuel cell, a housing that houses the fuel cell and the voltage conversion device and has an air vent formed therein, and a fan that is driven by the rotation of multiple blade members and is provided in the housing so that the outside of the housing communicates with the inside of the housing through the gaps between the multiple blade members, and when the fan is driven, an airflow that flows between the air vent and the fan is generated inside the housing, and the fuel cell system is characterized in that it has a covering wall that covers a portion of the electrical components so as not to obstruct the flow of the airflow, one of the fan and the electrical component is located downstream of the other in the flow direction of the airflow, and the covering wall has a first wall portion located between the fan and the electrical component in the flow direction of the airflow, and a second wall portion located above the electrical component in the vertical direction.

[0006] According to the above configuration, water that has entered the housing and is heading toward the electrical components collides with the first wall portion and the second wall portion, and is therefore less likely to get on the electrical components. Therefore, even if water gets into the housing from the outside through the gaps between the multiple blade members, it is possible to prevent the electrical components from getting wet.

[0007] The fuel cell system may include a bracket for attaching the voltage conversion device to the housing, and the cover wall may be integrated with the bracket. According to the above configuration, the covering wall can be attached to the housing by simply attaching the bracket to the housing, thereby improving work efficiency.

[0008] In a fuel cell system, if the side on which the electrical component is attached to the bracket is defined as the fixed side and the side on which the electrical component is not attached to the bracket is defined as the non-fixed side, the covering wall may have a third wall portion provided on the non-fixed side of the electrical component.

[0009] With this configuration, even if some of the water that has entered the housing heads toward the non-fixed side of the electrical component, the water collides with the third wall portion and is therefore less likely to get on the electrical component, thereby further reducing the risk of water getting on the electrical component.

[0010] In the fuel cell system, the third wall portion may have a larger dimension in the vertical direction as it approaches the fan in the flow direction of the airflow. With the above configuration, the closer the electrical components are to the fan in the airflow direction, the more likely they are to be splashed with water that has seeped into the housing. However, these areas can be covered over a wider area by the third wall. In contrast, the farther the electrical components are from the fan in the airflow direction, the less likely they are to be splashed with water that has seeped into the housing. However, the area covered by the third wall can be reduced. Therefore, the electrical components can be prevented from being splashed with water while heat dissipation from the electrical components can be improved.

[0011] In a fuel cell system, the fuel cell system may have a drainage tank into which water produced during power generation by the fuel cell is discharged, and a partition wall that separates the internal space of the housing into a lower space and an upper space that is located above the lower space in the vertical direction, and the fuel cell may be located in the upper space, and the electrical components, the drainage tank, and the covering wall may be located in the lower space.

[0012] According to the above configuration, the dimensions of the covering wall in the airflow direction can be set so that the partition wall blocks some of the water flowing toward the electrical components, thereby exposing the parts of the electrical components that are less likely to be exposed to water and allowing them to dissipate heat. This makes it possible to improve heat dissipation from the electrical components while suppressing water exposure to the electrical components. [Effects of the Invention]

[0013] According to this invention, it is possible to prevent the electrical components from being exposed to water. [Brief explanation of the drawings]

[0014] [Figure 1]1 is a partially cutaway perspective view showing a fuel cell system according to an embodiment. [Figure 2] FIG. 1 is a configuration diagram of a fuel cell system. [Figure 3] FIG. 1 is a cross-sectional view of a fuel cell system. [Figure 4] FIG. 1 is a perspective view showing a part of a fuel cell system. [Figure 5] FIG. 1 is a cross-sectional view schematically showing a fuel cell system. DETAILED DESCRIPTION OF THE INVENTION

[0015] An embodiment of a fuel cell system will now be described with reference to Figures 1 to 5. The fuel cell system is mounted on an industrial vehicle (not shown). <Overall configuration of fuel cell system> 1 and 2, a fuel cell system 10 includes a fuel cell stack 12 as a fuel cell, a DC / DC converter 30 as a voltage conversion device that converts the output voltage of the fuel cell stack 12, and a housing 11. The fuel cell system 10 also includes a hydrogen tank 13, an air compressor 14, a gas-liquid separator 15a, a diluter 15, and a drainage tank 16.

[0016] The fuel cell system 10 includes a hydrogen supply path 17 that connects an anode (not shown) of the fuel cell stack 12 to a hydrogen tank 13, and an air supply path 18 that connects a cathode (not shown) of the fuel cell stack 12 to an air compressor 14. The fuel cell system 10 also includes a discharge path 19a that connects the fuel cell stack 12 to a diluter 15, and a drain path 19b that connects the diluter 15 to a drain tank 16.

[0017] The fuel cell system 10 includes a heat exchanger 21 that exchanges heat between the outside air and a heat exchange medium, a fan 20, and a circulation flow path 22 that circulates the heat exchange medium between the fuel cell stack 12 and the heat exchanger 21. Cooling water is used as the heat exchange medium, but other media may also be used.

[0018] <Case> As shown in FIG. 1 , the housing 11 has a bottom wall 11a, a top wall 11b, and a cylindrical peripheral wall 11c connecting the periphery of the bottom wall 11a and the periphery of the top wall 11b. The bottom wall 11a, the top wall 11b, and the peripheral wall 11c define an internal space S of the housing 11. In the drawings, the fuel cell system 10 is placed on a horizontal plane, with the direction of gravity indicated by the Z axis and directions along the horizontal plane indicated by the X axis and the Y axis. The X axis, the Y axis, and the Z axis are perpendicular to one another. In the following description, the direction parallel to the Z axis is also referred to as the vertical direction Z, and the direction parallel to the X axis is also referred to as the horizontal direction X. The direction parallel to the Y axis is also referred to as the depth direction Y. Therefore, the depth direction Y is a direction perpendicular to both the horizontal direction X and the vertical direction Z.

[0019] In the housing 11, the bottom wall 11a and the top wall 11b face each other in the vertical direction Z. The peripheral wall 11c has a first side wall 11d and a second side wall 11e facing each other in the horizontal direction X, and a third side wall 11f and a fourth side wall 11g facing each other in the depth direction Y. A plurality of ventilation holes 11h are formed in the first side wall 11d. That is, the ventilation holes 11h are formed in the housing 11. Each of the plurality of ventilation holes 11h penetrates the first side wall 11d in the plate thickness direction. A through hole 11i is formed in the second side wall 11e of the housing 11. The through hole 11i penetrates the second side wall 11e in the plate thickness direction.

[0020] The housing 11 houses the fuel cell stack 12, the air compressor 14, the drain tank 16, and the heat exchanger 21. Although not shown in Fig. 1, the housing 11 also houses the hydrogen tank 13, the gas-liquid separator 15a, the diluter 15, the hydrogen supply channel 17, the air supply channel 18, the discharge channel 19a, and the drain channel 19b.

[0021] <Fuel cell system components> The fuel cell system 10 has a partition wall 40. The partition wall 40 divides the space S inside the housing 11 into a lower space S1 and an upper space S2 located above the lower space S1 in the vertical direction Z. The partition wall 40 has a flat plate shape extending perpendicular to the vertical direction Z. The partition wall 40 is fixed to the housing 11.

[0022] The partition wall 40 may extend in the horizontal direction X from the first side wall 11d to just before the second side wall 11e of the housing 11. The partition wall 40 may extend in the depth direction Y between the third side wall 11f and the fourth side wall 11g of the housing 11. The partition wall 40 may be fixed to, for example, the peripheral wall 11c of the housing 11. In this case, one end of the partition wall 40 in the depth direction Y is fixed to the fourth side wall 11g. The other end of the partition wall 40 in the depth direction Y is fixed to the third side wall 11f. The end of the partition wall 40 in the direction opposite to the horizontal direction X is fixed to the first side wall 11d.

[0023] The fuel cell stack 12 and the air compressor 14 are located in the upper space S2. The fuel cell stack 12 and the air compressor 14 are supported by a partition wall 40. The fuel cell stack 12 and the air compressor 14 are positioned above the bottom wall 11a by the partition wall 40. The DC / DC converter 30 and the drainage tank 16 are located in the lower space S1. The DC / DC converter 30 and the drainage tank 16 are positioned below the fuel cell stack 12.

[0024] As shown in FIG. 2, a fuel cell stack 12 generates electricity to be supplied to a load mounted on an industrial vehicle (not shown). The fuel cell stack 12 is made up of a plurality of fuel cell cells stacked together. The fuel cell cells are solid molecular fuel cells. The fuel cell stack 12 generates direct current electrical energy by reacting hydrogen supplied from a hydrogen tank 13 via a hydrogen supply path 17 with oxygen in the air supplied from an air compressor 14 via an air supply path 18. The fuel cell stack 12 generates electricity using hydrogen as a fuel gas and oxygen in the air as an oxidant gas. Water is produced in the fuel cell stack 12 as a result of power generation.

[0025] The discharge path 19a discharges anode off-gas, which is exhaust gas containing hydrogen discharged from the fuel cell stack 12, to the diluter 15. The discharge path 19a also discharges cathode off-gas, which is exhaust gas containing oxygen discharged from the fuel cell stack 12 and water produced as the fuel cell stack 12 generates electricity, to the diluter 15.

[0026] The diluter 15 has a gas-liquid separator 15a therein. The gas-liquid separator 15a has a function of separating hydrogen and water from the anode off-gas discharged to the diluter 15. The water separated by the gas-liquid separator 15a is discharged to the drainage tank 16 via the drainage channel 19b. That is, water produced in conjunction with the power generation of the fuel cell stack 12 is discharged to the drainage tank 16. The drainage tank 16 is made of metal. The diluter 15 has a function of diluting the hydrogen separated by the gas-liquid separator 15a with the cathode off-gas.

[0027] The circulation flow path 22 circulates the cooling water between the fuel cell stack 12 and the heat exchanger 21. The circulation flow path 22 has an outward flow path 22a, a return flow path 22b, a pump (not shown), and heat exchange flow paths (not shown) routed within the fuel cell stack 12 and the heat exchanger 21. The outward flow path 22a is a flow path for flowing the cooling water from the heat exchanger 21 toward the fuel cell stack 12. The return flow path 22b is a flow path for flowing the cooling water from the fuel cell stack 12 toward the heat exchanger 21. The pump (not shown) circulates the cooling water through the circulation flow path 22.

[0028] The cooling water circulates through the circulation flow path 22 and flows through the outward path 22a into the heat exchange flow path in the fuel cell stack 12, absorbing heat generated in the fuel cell stack 12 and cooling the fuel cell stack 12. The cooling water flows through the return path 22b into the heat exchange flow path in the heat exchanger 21 and is cooled by heat exchange with the outside air.

[0029] As shown in FIG. 1, the heat exchanger 21 is disposed on the second side wall 11e of the housing 11. The fuel cell stack 12 and the heat exchanger 21 are disposed side by side in the horizontal direction X. The heat exchanger 21 has a case 21a. The case 21a is attached to the second side wall 11e so as to close the through-hole 11i in the second side wall 11e. A case hole 21b that opens into the interior of the housing 11 is formed in the center of the case 21a. The case hole 21b communicates with the outside of the housing 11 via the through-hole 11i in the second side wall 11e, and also communicates with the interior of the housing 11.

[0030] <Fan> The fan 20, together with the heat exchanger 21, faces the vent 11h in the horizontal direction X. The fan 20 is located away in the horizontal direction X from the end of the partition wall 40 in the horizontal direction X.

[0031] The fan 20 has a shaft member 20a and a plurality of blade members 20b arranged around the shaft member 20a. The fan 20 is driven by the rotation of the plurality of blade members 20b. The plurality of blade members 20b are connected to the shaft member 20a and are spaced apart from one another in the direction of rotation of the fan 20. A gap between the plurality of blade members 20b is referred to as gap G. The fan 20 is located inside the case hole 21b of the case 21a. Therefore, gap G communicates with the outside of the housing 11 via the through-hole 11i in the second side wall 11e, and also communicates with the inside of the housing 11. In other words, the fan 20 is arranged in the housing 11 so that the outside of the housing 11 communicates with the inside of the housing 11 via gap G.

[0032] In the fuel cell system 10, when the fan 20 is driven, an airflow is generated inside the housing 11, flowing between the vent 11h and the fan 20. More specifically, when the fuel cell stack 12 generates electricity, the fan 20 is driven, and air is drawn from the outside of the housing 11 into the inside of the housing 11 through the vent 11h. Inside the housing 11, an airflow is generated that flows from the vent 11h toward the fan 20. Inside the housing 11, the direction of the airflow from the vent 11h toward the fan 20 is defined as the airflow direction F. Because the fan 20 and the vent 11h are opposite each other in the horizontal direction X, the airflow direction F is generated in the horizontal direction X. The cooling water that flows into the heat exchanger 21 from the fuel cell stack 12 is cooled by forced heat exchange with outside air by the air blown from the fan 20 in the heat exchanger 21.

[0033] <DC / DCコンバータ> 3 and 4, the DC / DC converter 30 includes, as components, a plurality of reactors 35 and a switching unit 36 ​​having switching elements (not shown). In this embodiment, the reactors 35 correspond to electrical components. The DC / DC converter 30, which serves as a voltage conversion device, includes electrical components.

[0034] 5, in the horizontal direction X, the multiple reactors 35 are located closer to the fan 20 than the switching unit 36. The fan 20 is located downstream of the reactors 35 in the gas flow direction F. The reactors 35 and the switching unit 36 ​​are located in the lower space S1.

[0035] As shown in FIG. 4, the heat dissipation unit 32 is thermally coupled to the switching unit 36. The heat dissipation unit 32 has an attachment member 33 for attaching the heat dissipation unit 32 to the switching unit 36, and a plurality of heat dissipation fins 34 integral with the attachment member 33. The heat dissipation unit 32 is made of metal. The attachment member 33 is fixed to the back surface 36a of the switching unit 36. Each of the plurality of heat dissipation fins 34 is a rectangular plate fin. The plurality of heat dissipation fins 34 are arranged side by side at intervals in the vertical direction Z. The reactor 35 has a core (not shown) and a coil component wound around the core.

[0036] 5, the DC / DC converter 30 has three reactors 35. The switching unit 36 ​​and the three reactors 35 are aligned in a row in the horizontal direction X. In other words, the switching unit 36 ​​and the three reactors 35 are aligned in the airflow direction F.

[0037] <bracket> The fuel cell system 10 has a bracket 50. The bracket 50 is used to attach a DC / DC converter 30, which serves as a voltage conversion device, to the housing 11. The DC / DC converter 30 is attached to the bottom wall 11a of the housing 11 by the bracket 50.

[0038] The bracket 50 is made of a metal plate. The bracket 50 is formed by bending a metal body. The bracket 50 has a fixing plate 51 for fixing the bracket 50 to the bottom wall 11a of the housing 11, and a mounting plate 61 that protrudes upward in the vertical direction Z from the fixing plate 51. The multiple reactors 35 and the switching unit 36 ​​are attached to the mounting plate 61.

[0039] The fixing plate 51 has a rectangular plate shape in a plan view seen from above in the vertical direction Z. The fixing plate 51 is fixed to the bottom wall 11a by screwing bolts 51a, which penetrate the fixing plate 51 in the plate thickness direction, into the bottom wall 11a. Note that the method of fixing the fixing plate 51 to the bottom wall 11a is not limited to fixing with the bolts 51a. The fixing plate 51 may be fixed to the bottom wall 11a by welding, or the fixing plate 51 may be fixed to the bottom wall 11a by adhering it to the bottom wall 11a with an adhesive.

[0040] The mounting plate 61 is adjacent to the drainage tank 16 in the depth direction Y. The mounting plate 61 protrudes from one of a pair of edges of the fixed plate 51 extending in the horizontal direction X that is closer to the drainage tank 16 in the depth direction Y. The mounting plate 61 is bent so as to be concave toward the drainage tank 16. In the depth direction Y, the side where the reactor 35 is mounted to the mounting plate 61 of the bracket 50 is referred to as the fixed side Y1, and the side where the reactor 35 is not mounted to the mounting plate 61 of the bracket 50 is referred to as the non-fixed side Y2.

[0041] 5, the fixing plate 51 of the bracket 50 is fixed to the bottom wall 11a below the partition wall 40 in the vertical direction Z. Therefore, the bracket 50 is disposed below the partition wall 40. Since the DC / DC converter 30 is attached to the bracket 50, the multiple reactors 35 and the switching unit 36 ​​are disposed below the partition wall 40 and to the side of the drainage tank 16.

[0042] <Coated wall> The fuel cell system 10 has a covering wall 70 that covers a portion of the reactor 35 so as not to obstruct the flow of air. The covering wall 70 is located in the lower space S1. The covering wall 70 has a first wall portion 71, a second wall portion 72, and a third wall portion 73.

[0043] As shown in FIG. 4 , the first wall portion 71 is located between the fan 20 and the reactor 35, which serves as an electrical component, in the airflow direction F. The first wall portion 71 has a flat plate shape extending perpendicular to the horizontal direction X. In a plan view seen from the horizontal direction X, the first wall portion 71 has a rectangular shape with a lower portion cut out on the side farther from the drainage tank 16. The first wall portion 71 covers an upper portion in the vertical direction Z of the reactor 35, of the multiple reactors 35, that is located at the end closer to the fan 20 in the horizontal direction X. Of the reactor 35 that is located at the end farther from the fan 20 in the horizontal direction X, a lower portion in the vertical direction Z is exposed from the first wall portion 71.

[0044] The first wall portion 71 has a first edge 71a located at the upper end of the first wall portion 71, and a second edge 71b and a third edge 71c extending in the vertical direction Z. The third edge 71c is located closer to the drainage tank 16 (fixed side Y1) than the second edge 71b.

[0045] The second wall portion 72 is located above the reactor 35, which serves as an electrical component, in the vertical direction Z. The second wall portion 72 extends from a first end edge 71a of the first wall portion 71. The second wall portion 72 has a flat plate shape extending perpendicular to the vertical direction Z. In a plan view seen from the vertical direction Z, the second wall portion 72 has a rectangular shape. The second wall portion 72 covers the multiple reactors 35 from above in the vertical direction Z. In detail, the second wall portion 72 covers two of the three reactors 35 that are located closer to the fan 20 in the horizontal direction X and a portion of the reactor 35 that is located at the end farther from the fan 20 in the horizontal direction X. The portion of the multiple reactors 35 that is located at the end farther from the fan 20 in the horizontal direction X is exposed from the second wall portion 72.

[0046] The second wall portion 72 has a first long edge portion 72a and a second long edge portion 72b extending in the horizontal direction X, and a first short edge portion 72c and a second short edge portion 72d extending in the depth direction Y. The first long edge portion 72a is located closer to the drainage tank 16 in the depth direction Y (on the fixed side Y1) than the second long edge portion 72b. The first long edge portion 72a is in contact with the mounting plate 61 of the bracket 50. The first long edge portion 72a may be fixed to the mounting plate 61. The first short edge portion 72c is located closer to the fan 20 in the horizontal direction X than the second short edge portion 72d. The first short edge portion 72c is connected to a first edge 71a of the first wall portion 71.

[0047] The third wall portion 73 covers a part of the reactor 35 serving as an electrical component on the side farther from the drainage tank 16 in the depth direction Y (non-fixed side Y2). In this embodiment, the depth direction Y corresponds to the orthogonal direction that is perpendicular to the airflow direction F and the vertical direction Z. The third wall portion 73 extends from the second long edge portion 72b of the second wall portion 72. The third wall portion 73 has a flat plate shape extending in the vertical direction Z. The third wall portion 73 is provided closer to the non-fixed side Y2 than the multiple reactors 35 serving as electrical components. The third wall portion 73 has a shape whose width in the vertical direction Z narrows from the side closer to the fan 20 to the side farther from the fan 20. The third wall portion 73 covers the multiple reactors 35 on the side farther from the drainage tank 16 in the depth direction Y (non-fixed side Y2). In detail, the third wall portion 73 covers two of the three reactors 35 that are located closer to the fan 20 in the horizontal direction X and a portion of the reactor 35 that is located at the end farther from the fan 20. Of the multiple reactors 35, the portion of the reactor 35 that is located at the end farther from the fan 20 in the horizontal direction X is exposed from the third wall portion 73.

[0048] The third wall portion 73 has a first edge portion 73a extending in the horizontal direction X, a second edge portion 73b located lower than the first edge portion 73a in the vertical direction Z, and a third edge portion 73c and a fourth edge portion 73d extending in the vertical direction Z. The first edge portion 73a is connected to the second long edge portion 72b of the second wall portion 72. The third edge portion 73c is located closer to the fan 20 in the horizontal direction X than the fourth edge portion 73d. The third edge portion 73c is connected to the second end edge 71b of the first wall portion 71.

[0049] The second edge portion 73b extends downward in the vertical direction Z as it approaches the first wall portion 71 in the horizontal direction X. The dimension of the third wall portion 73 in the vertical direction Z is also referred to as dimension L1. The dimension L1 of the third wall portion 73 in the vertical direction Z increases as it approaches the fan 20 in the airflow direction F.

[0050] The second wall portion 72 is spaced apart from the reactors 35 in the vertical direction Z. The third wall portion 73 is spaced apart from the reactors 35 in the depth direction Y. The covering wall 70 has an opening 75 that opens toward the reactor 35 in the horizontal direction X. The opening 75 is formed by a second short edge portion 72d of the second wall portion 72 and a fourth edge portion 73d of the third wall portion 73. The opening 75 communicates with gaps between the second wall portion 72 and the third wall portion 73 and the reactors 35. Therefore, airflow is generated in the flow direction F from the opening 75 to gaps between the second wall portion 72 and the third wall portion 73 and the reactors 35. In this way, the covering wall 70 covers a portion of the reactors 35 so as not to obstruct the flow of airflow.

[0051] The covering wall 70 has an extending portion 76 extending from the third edge 71c of the first wall portion 71. The extending portion 76 is in the shape of a flat plate extending perpendicular to the depth direction Y. The extending portion 76 is fixed to the mounting plate 61 by screwing a bolt 76a that passes through the extending portion 76 in the plate thickness direction into the mounting plate 61. By fixing the covering wall 70 to the bracket 50 in this manner, the covering wall 70 is integrated with the bracket 50.

[0052] <Dimensions of the covering wall in the direction of airflow> As shown in FIG. 5, when rainwater splashes on the fuel cell system 10, water W may seep into the housing 11 through the gaps G between the blade members 20b of the fan 20. In this case, the partition wall 40 may block some of the water W flowing toward the three reactors 35, which serve as electrical components. However, if the partition wall 40 were to cover the entire reactor 35, cooling of the reactor 35 may be hindered. Of the three reactors 35, the reactor 35 farthest from the fan 20 in the horizontal direction X is less likely to be splashed with water W. In this embodiment, the dimensions of the covering wall 70 in the airflow direction F are set so that the portion less likely to be splashed with water W is exposed from the covering wall 70. Specifically, it is assumed that water W seeps into the housing 11 through the gaps G between the blade members 20b of the fan 20 so that the angle A with respect to the bottom wall 11a is 45 degrees. Under this assumption, the dimension L2 of the second wall portion 72 and the third wall portion 73 of the covering wall 70 in the airflow direction F is set so as to expose a portion of the reactor 35 that is not directly exposed to the water W. The dimension L2 is also the dimension of the second wall portion 72 and the third wall portion 73 in the horizontal direction X.

[0053] <Air cooling by airflow> When the fuel cell stack 12 generates power, the fan 20 is driven to draw air from the outside of the housing 11 into the inside of the housing 11 through the vent 11h. Inside the housing 11, an airflow is generated from the vent 11h toward the fan 20. This airflow causes air to pass through the heat exchanger 21, thereby air-cooling the heat exchanger 21. This improves the cooling efficiency of the coolant in the heat exchange flow path inside the heat exchanger 21. As a result, the fuel cell stack 12, which is cooled using coolant, can also be cooled efficiently.

[0054] The switching unit 36 ​​and reactor 35 of the DC / DC converter 30 generate heat as the fuel cell stack 12 generates power. As air flows from the vent 11h toward the fan 20, the air flows along the heat dissipation fins 34 of the heat dissipation unit 32 and the mounting member 33. This causes heat exchange between the heat dissipation fins 34 and the mounting member 33 and the air. As a result, the switching unit 36 ​​is air-cooled by the heat dissipation unit 32.

[0055] As airflow is generated from the vent 11h toward the fan 20, air flows along the portions of the three reactors 35 exposed from the covering wall 70, and also flows through the gaps between the second wall portion 72 and the third wall portion 73 and the plurality of reactors 35. As a result, the three reactors 35 exchange heat with the air, and the three reactors 35 are air-cooled.

[0056] [Effect] Next, the operation of the fuel cell system 10 will be described. If rainwater falls on the fuel cell system 10, water W may seep into the housing 11 through the gaps G between the blade members 20b of the fan 20. At this time, some of the water W that seeps into the housing 11 flows toward the three reactors 35, which serve as electrical components. The water W flowing toward the three reactors 35 from the horizontal direction X collides with the first wall portion 71. The water W flowing toward the three reactors 35 from above in the vertical direction Z collides with the second wall portion 72. In this way, the water W flowing toward the three reactors 35 collides with the covering wall 70, making it less likely to splash on the three reactors 35.

[0057] [effect] According to the above embodiment, the following effects can be obtained. (1) The fuel cell system 10 has a covering wall 70 that covers a portion of the multiple reactors 35 serving as electrical components so as not to obstruct the flow of airflow. The covering wall 70 has a first wall portion 71 located between the fan 20 and the multiple reactors 35 in the airflow direction F, and a second wall portion 72 located above the multiple reactors 35 in the vertical direction Z. Therefore, even if water W enters the interior of the housing 11 from the outside through the gaps G between the multiple blade members 20b, the water W collides with the first wall portion 71 and the second wall portion 72, and is therefore less likely to splash on the three reactors 35. This makes it possible to prevent the three reactors 35 from being exposed to water.

[0058] (2) The fuel cell system 10 has a bracket 50 that mounts the DC / DC converter 30, which serves as a voltage conversion device, to the housing 11. The covering wall 70 is integrated with the bracket 50. Therefore, the mounting of the covering wall 70 to the housing 11 can be completed by the process of mounting the bracket 50 to the housing 11, thereby improving work efficiency.

[0059] (3) The covering wall 70 has a third wall portion 73 that is provided closer to the non-fixed side Y2 than the three reactors 35 that serve as electrical components. Therefore, even if some of the water W that has entered the housing 11 heads toward the non-fixed side Y2 of the three reactors 35, the water W collides with the third wall portion 73 and is therefore less likely to splash onto the three reactors 35. This further reduces the likelihood of the three reactors 35 being wet.

[0060] (4) The dimension L1 of the third wall portion 73 in the vertical direction Z increases as the third wall portion 73 approaches the fan 20 in the airflow direction F. The closer the portion of the reactor 35 is to the fan 20 in the airflow direction F, the more likely it is that water W that has infiltrated into the housing 11 will splash on it, but this portion can be covered over a wide area by the third wall portion 73. In contrast, the portion of the reactor 35 that is farther from the fan 20 in the airflow direction F is less likely to be splashed with water W that has infiltrated into the housing 11, but the area that is covered by the third wall portion 73 can be reduced in this portion. Therefore, the heat dissipation from the three reactors 35 can be improved while preventing the three reactors 35 from being splashed with water.

[0061] (5) The fuel cell system 10 has a partition wall 40 that divides the space S inside the housing 11 into a lower space S1 and an upper space S2 that is located higher than the lower space S1 in the vertical direction Z. The three reactors 35 serving as electrical components and the covering wall 70 are located in the lower space S1. Therefore, the partition wall 40 blocks some of the water W flowing toward the three reactors 35 serving as electrical components, and the dimensions of the covering wall 70 in the airflow direction F can be set so that portions of the reactors 35 that are less likely to be exposed to water W are exposed from the covering wall 70 and can dissipate heat. Therefore, the heat dissipation from the three reactors 35 can be improved while preventing the three reactors 35 from being exposed to water.

[0062] [Example of change] The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0063] The drain tank 16 may be made of resin. The fuel cell stack 12 may be located in the lower space S1. The three reactors 35 as electrical components and the covering wall 70 may be located in the upper space S2.

[0064] The partition wall 40 does not have to be fixed to the peripheral wall 11c of the housing 11. For example, the partition wall 40 may be provided with legs extending from the partition wall 40 to the bottom wall 11a, and the legs may be fixed to the bottom wall 11a, thereby fixing the partition wall 40 to the housing 11.

[0065] The partition wall 40 may be omitted from the fuel cell system 10. The mounting plate 61 may be a flat plate that is not bent. The bracket 50 may have only the mounting plate 61. In this case, since the bracket 50 does not have the fixing plate 51, the bracket 50 may be attached to the bottom wall 11a by welding the mounting plate 61 to the bottom wall 11a.

[0066] The method of integrating the covering wall 70 with the bracket 50 is not limited to fixing using the bolts 76a. For example, the covering wall 70 may be integrated with the bracket 50 by welding the covering wall 70 to the mounting plate 61. For example, the covering wall 70 may be integrated with the bracket 50 by adhering and fixing the covering wall 70 to the mounting plate 61 with an adhesive.

[0067] The bracket 50 may be omitted from the fuel cell system 10. In this case, the cover wall 70 may further include a wall portion that covers the three reactors 35 serving as electrical components from the drainage tank 16 side in the depth direction Y.

[0068] The dimension L1 of the third wall portion 73 in the vertical direction Z does not necessarily increase as it approaches the fan 20 in the airflow direction F. For example, the dimension L1 of the third wall portion 73 in the vertical direction Z may be the same from the third edge portion 73c to the fourth edge portion 73d.

[0069] The third wall portion 73 may be omitted from the covering wall 70. The number of reactors 35 may be changed depending on the number of switching units 36 . The reactors 35 do not have to be aligned in a row in the airflow direction F. For example, two reactors 35 may be aligned in the vertical direction Z upstream of the airflow direction F, and one reactor 35 may be aligned downstream of the two reactors 35. For example, three reactors 35 may be aligned in the vertical direction Z.

[0070] The electrical components covered by the covering wall 70 may include the switching unit 36. In this case, for example, by making the dimension L2 of the covering wall 70 larger than in the above embodiment, the covering wall 70 can cover not only the reactor 35 but also the switching unit 36.

[0071] The electrical component covered by the covering wall 70 may be the switching unit 36 ​​instead of the reactor 35. In this case, the switching unit 36 ​​is located closer to the fan 20 in the horizontal direction X than the reactor 35, for example.

[0072] The fuel cell system 10 does not have to include the gas-liquid separator 15a. In this case, the discharge path 19a is connected to the diluter 15. The fuel cell does not have to be a stack of multiple fuel cells, but may be a single fuel cell.

[0073] The direction F of the airflow that flows between the vent 11h and the fan 20 due to the driving of the fan 20 may be the direction from the fan 20 toward the vent 11h. In this case, the electrical component is located downstream of the fan 20 in the direction of the airflow F. In short, it is sufficient that one of the fan 20 and the electrical component is located downstream of the other in the direction of the airflow F. [Explanation of symbols]

[0074] F...flow direction, G...gap, L1, L2...dimension, S...space, S1...lower space, S2...upper space, W...water, Y1...fixed side, Y2...non-fixed side, Z...vertical direction, 10...fuel cell system, 11...housing, 11h...vent, 12...fuel cell stack, 16...drainage tank, 20...fan, 20b...blade member, 30...DC / DC converter, 35...reactor, 36...switching unit, 40...partition wall, 50...bracket, 70...covering wall, 71...first wall portion, 72...second wall portion, 73...third wall portion.

Claims

1. A fuel cell; a voltage conversion device including an electrical component for changing the output voltage of the fuel cell; a housing that houses the fuel cell and the voltage conversion device and has a vent hole; a fan that is driven by the rotation of a plurality of blade members and is provided in the housing so that the outside of the housing communicates with the inside of the housing via gaps between the plurality of blade members; a fuel cell system in which, when the fan is driven, an airflow that flows between the vent and the fan is generated inside the housing, a covering wall that covers a part of the electrical component so as not to obstruct the flow of the air; one of the fan and the electrical component is located downstream of the other in the direction of the airflow, a first wall portion located between the fan and the electrical component in the flow direction of the airflow, and a second wall portion located above the electrical component in the vertical direction.

2. the fuel cell system has a bracket for attaching the voltage conversion device to the housing, 2. The fuel cell system according to claim 1, wherein the covering wall is integrated with the bracket.

3. The side where the electrical component is attached to the bracket is defined as a fixed side, and the side where the electrical component is not attached to the bracket is defined as a non-fixed side.

3. The fuel cell system according to claim 2, wherein the covering wall has a third wall portion provided on the non-fixed side of the electrical component.

4. 4. The fuel cell system according to claim 3, wherein the third wall portion has a dimension in the vertical direction that increases as it approaches the fan in the flow direction of the airflow.

5. the fuel cell system includes a drainage tank into which water generated by power generation of the fuel cell is discharged, and a partition wall that divides the space inside the housing into a lower space and an upper space located above the lower space in the vertical direction; the fuel cell is located in the upper space, 5. The fuel cell system according to claim 1, wherein the electrical components, the drainage tank, and the covering wall are located in the lower space.

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