Fuel cell unit

Abstract

Fuel cell unit (100, 200, 300, 400), comprising: a fuel cell stack (10) with: a cell stack (12) in which unit cells are stacked in a first direction; a first connection (13a) which is accordingly arranged at a first end of the cell stack (12) in the first direction; and a second terminal (13b) which is located at a second end of the cell stack (12) in the first direction; an end plate (16) which is located on a side of the cell stack (12) opposite the first terminal (13a); a power converter (20) that converts an output power of the fuel cell stack (10); a stacking housing (40) that accommodates the fuel cell stack (10); a power converter housing (50) that accommodates the power converter (20) and is attached to the stacking housing (40); a first busbar (60) that electrically connects the first terminal (13a) and the power transformer (20) in the stacking housing (40) and the power transformer housing (50); and a second busbar (61) which electrically connects the second terminal (13b) and the power transformer (20) in the stacking housing (40) and the power transformer housing (50), where the first connection (13a) comprises a first projecting section (17a) that extends from the cell stack (12) and is connected to the first busbar (60), the second connection (13b) comprises a second projecting section (17b) that extends from the cell stack (12) and is connected to the second busbar (61), the stacking housing (40) comprises: a frame-shaped flange (42) which defines a first opening (41) on its inside and is attached to the end plate (16) so that the fuel cell stack (10) is housed in the stack housing (40); a first bottom wall (43), wherein the fuel cell stack (10) is arranged sandwich-like between the first bottom wall (43) and the end plate (16) in the first direction; a first side wall (44) arranged between the fuel cell stack (10) and the power converter (20), connected between the flange (42) and the first bottom wall (43), and comprising a second opening (48) that allows the first and second busbars (60, 61) to be connected accordingly to the first and second terminals (13a, 13b); and a second side wall (45) connected between the flange (42) and the first bottom wall (43), wherein the fuel cell stack (10) is arranged between the first side wall (44) and the second side wall (45) in a second direction perpendicular to the first direction, the first side wall (44) is inclined in relation to the first bottom wall (43) such that the distance between the first side wall (44) and the second side wall (45) on one side of the flange (42) is greater than on one side of the first bottom wall (43), an angle between the first side wall (44) and the first bottom wall (43) on one side of the fuel cell stack (10) is greater than an angle between the second side wall (45) and the first bottom wall (43) on one side of the fuel cell stack (10), and the first side wall (44) overlaps the second projecting section (17b) of the second connection (13b) in a third direction perpendicular to the first direction and the second direction.

Description

AREA OF INVENTION

[0001] The present invention relates to a fuel cell unit. BACKGROUND

[0002] A power converter, such as a converter for converting the output power of a fuel cell stack, is used. For example, a fuel cell unit is known in which a stack housing comprising the fuel cell stack is connected to a power converter housing comprising the power converter, and in which the fuel cell stack is electrically connected to the power converter via busbars in the stack housing and in the power converter housing (see, for example, Japanese patent application JP 2017-073 199 A).

[0003] In Japanese patent application JP 2017-073 199 A, a side wall of the stacking housing is perpendicular to a bottom wall of the stacking housing. With regard to the manufacturability of the stacking housing, a draft angle can be defined by angling the side wall of the stacking housing relative to the bottom wall. However, if the side wall of the stacking housing is slanted relative to the bottom wall, the fuel cell unit may become larger. SUMMARY OF THE INVENTION

[0004] It is therefore an object of the present invention to suppress an increase in the size of a fuel cell unit.

[0005] The aforementioned problem is solved by a fuel cell unit comprising: a fuel cell stack with: a cell stack in which unit cells are stacked in a first direction; a first terminal arranged accordingly at a first end of the cell stack in the first direction; and a second terminal arranged at a second end of the cell stack in the first direction; an end plate arranged on a side of the cell stack opposite the first terminal; a power converter that converts the output power of the fuel cell stack; a stack housing that accommodates the fuel cell stack; a power converter housing that accommodates the power converter and is attached to the stack housing; a first busbar that electrically connects the first terminal and the power converter in the stack housing and the power converter housing;and a second busbar electrically connecting the second terminal and the power converter in the stack housing and the power converter housing, wherein the first terminal comprises a first projecting section extending from the cell stack and connected to the first busbar, and the second terminal comprises a second projecting section extending from the cell stack and connected to the second busbar, the stack housing comprising: a frame-shaped flange defining a first opening on its inside and attached to the end plate such that the fuel cell stack is housed in the stack housing; a first bottom wall, wherein the fuel cell stack is sandwiched between the first bottom wall and the end plate in the first direction;a first side wall, which is arranged between the fuel cell stack and the power converter, is connected between the flange and the first bottom wall and includes a second opening that allows the first and second busbars to be connected accordingly to the first and second terminals;and a second side wall connected between the flange and the first bottom wall, wherein the fuel cell stack is arranged between the first side wall and the second side wall in a second direction perpendicular to the first direction, wherein the first side wall is inclined with respect to the first bottom wall such that a distance between the first side wall and the second side wall on one side of the flange is greater than on one side of the first bottom wall, an angle between the first side wall and the first bottom wall on one side of the fuel cell stack is greater than an angle between the second side wall and the first bottom wall on one side of the fuel cell stack, and the first side wall overlaps the second projecting section of the second connection in a third direction perpendicular to the first direction and the second direction.

[0006] The angle between the second side wall and the first bottom wall on the side of the fuel cell stack can be a right angle.

[0007] The power converter housing can include a second bottom wall, wherein the power converter can be arranged between the second bottom wall and the first side wall in the second direction; components of the power converter can include a first component; of the components, an end section of the first component can be located furthest from the second bottom wall on one side of the first side wall; the first component can be arranged on one side of the first bottom wall with respect to a center between the flange and the first bottom wall in the first direction.

[0008] The components can include the first component, a second component, and a third component; the distance between the second bottom wall and an end section of the second component on one side of the first side wall can be smaller than the distance between the second bottom wall and the end section of the first component; the distance between the second bottom wall and an end section of the third component on one side of the first side wall can be smaller than the distance between the second bottom wall and the end section of the second component; and the third component, the second component, and the first component can be arranged in that order from the flange.

[0009] A component of the power converter components can include an end section on a first side wall that overlaps the first side wall in the first direction.

[0010] The power converter housing may have a third side wall along the second direction, and the third side wall may have an opening that allows the electrical connection of an external device to the power converter.

[0011] The flange may comprise: a flat surface to which the end plate is attached, and an outer circumferential surface extending continuously from an edge of the flat surface; the outer circumferential surface of the flange may be flat from one end to the other in the first direction, and the power converter housing may be attached to the outer circumferential surface of the flange.

[0012] The height of the stacking housing in the second direction can be at its maximum at the point where the flange is located.

[0013] The length of the first opening in the second direction can be greater than the length of the fuel cell stack in the second direction.

[0014] A distance between the first side wall and the second side wall at one end of the second opening on one side of the flange in the second direction can be greater than a length of the fuel cell stack in the second direction. EFFECTS OF INVENTION

[0015] According to the present invention, it is possible to suppress an increase in the size of a fuel cell unit. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a cross-sectional view of a fuel cell unit according to a first embodiment; Fig. Figure 2 is a perspective exploded view of the fuel cell unit of the first embodiment; Fig. Figure 3 is a view of a circuit configuration of the fuel cell unit according to the first embodiment; Fig. Figures 4A to 4D are views of a manufacturing process for a fuel cell unit according to the first embodiment; Fig. Figure 5 is a cross-sectional view of a fuel cell unit according to a first comparative example; Fig. Figure 6 is a cross-sectional view of a fuel cell unit according to a second comparative example; Fig. Figure 7 is a cross-sectional view of a stacked enclosure; Fig. Figure 8 is a cross-sectional view of a fuel cell unit according to a second embodiment; Fig. Figure 9A is a cross-sectional view of a fuel cell unit according to a third embodiment and Fig. Figure 9B is a cross-sectional view of the components of a boost converter housed in a converter enclosure; and Fig. Figure 10 is a cross-sectional view of a fuel cell unit according to a fourth embodiment. DETAILED DESCRIPTION

[0016] The following describes embodiments according to the present invention with reference to the drawings. [First embodiment]

[0017] Fig. Figure 1 is a cross-sectional view of a fuel cell unit according to a first embodiment. Fig. Figure 2 is a perspective exploded view of the fuel cell unit of the first embodiment. Some elements are shown on the back of a sheet of Fig. 1 shown without hatching. The same applies to the Fig. 4B to 10. As in the Fig. 1 and Fig. As shown in Figure 2, a fuel cell unit 100 according to the first embodiment consists of a fuel cell stack 10, an end plate 16, a boost converter 20, a stack housing 40, a converter housing 50, and the busbars 60 and 61. The boost converter 20 is an example of a power converter. The converter housing 50 is an example of a power converter housing.

[0018] The fuel cell stack 10 comprises a cell stack 12, terminals 13a and 13b, insulators 14a and 14b, and a pressure plate 15. The unit cells 11 of the cell stack 12 are stacked in the X direction. Terminals 13a and 13b are each located at both ends of the cell stack 12 in the X direction. Terminals 13a and 13b each have projecting sections 17a and 17b that extend from the cell stack 12.

[0019] The end plate 16 is located on a side opposite the cell stack 12 via the port 13a and the insulator 14a. Regarding the fuel cell stack 10, the insulator 14a, the port 13a, the cell stack 12, the port 13b, the insulator 14b, and the pressure plate 15 are stacked in that order on a main surface of the end plate 16. The end plate 16 is fastened to a flange 42 of the stack housing 40 by screws 71. The flange 42 defines an opening 41 on its inner side. The end plate 16 is attached to the flange 42 of the stack housing 40 such that the fuel cell stack 10 arranged on the end plate 16 is contained within the stack housing 40.

[0020] Terminals 13a and 13b are plates made of, for example, a metal such as copper, aluminum, or an alloy containing these, or of a conductive material such as dense carbon. Terminals 13a and 13b are arranged for the extraction of electrical energy generated by the unit cells 11. Insulators 14a and 14b are plates made of an insulating material such as rubber or resin. Insulator 14a is arranged to insulate terminal 13a from the end plate 16, which is located outside insulator 14a. Insulator 14b is arranged to insulate terminal 13b from the pressure plate 15, which is located outside insulator 14b. The pressure plate 15 is made of a material with high rigidity, such as a metal like stainless steel or an aluminum alloy. The pressure plate 15 is arranged to apply a compressive load to the cell stack 12 by means of a spring 70, as described later.The end plate 16 is made of a material with high rigidity, e.g. a metal material such as stainless steel or an aluminum alloy.

[0021] The stacking housing 40 is provided with the flange 42, which, as described above, defines the opening 41 on its inner side and has a frame shape. The opening 41 is arranged on one side in the X-direction. The stacking housing 40 has a bottom wall 43 on the other side in the X-direction and on the side opposite the end plate 16 above the fuel cell stack 10. The stacking housing 40 includes the side walls 44 to 47, which are connected between the flange 42 and the bottom wall 43. The stacking housing 40 is made of a high-rigidity material, e.g., a metal such as an aluminum alloy.

[0022] The spring 70 is positioned and compressed between the bottom wall 43 of the stack housing 40 and the pressure plate 15. Specifically, the spring 70 is positioned such that its length in the X-direction is shorter than that of the uncompressed spring 70. The reaction force of the spring 70 exerts a compressive load on the cell stack 12 in the stacking direction. The presence of the spring 70 allows the magnitude of the compressive load on the cell stack 12 to fall within a specific range, thus improving power generation and sealing performance. Additionally, the spring 70 does not necessarily need to be present. In this case, the end plate 16 can be attached to the flange 42 of the stack housing 40 in a state where the cell stack 12 is compressed in the stacking direction, so that the end plate 16 and the bottom wall 43 of the stack housing 40 can exert a compressive load on the fuel cell stack 10, which is positioned on the end plate 16.

[0023] The Unit Cell 11 is a polymer electrolyte fuel cell that generates electricity by supplying hydrogen (anode gas) and air (cathode gas) as reaction gases. The Unit Cell 11 comprises: a membrane electrode assembly, which is a power generator in which electrodes are arranged on both surfaces of an electrolyte membrane; and a pair of separators that sandwich the membrane electrode assembly between them. The electrolyte membrane is a solid polymer membrane made of a fluorinated resin material or a hydrocarbon resin material with a sulfonic acid group. The electrolyte membrane has good proton conductivity in the wet state. The electrode comprises a carbon support and an ionomer, which is a solid polymer with a sulfonic acid group and has good proton conductivity in the wet state. The carbon support carries a catalyst, e.g., platinum or a platinum-cobalt alloy, to assist in current generation.Power generation reaction. Each unit cell is equipped with collecting tubes for the flow of reaction gases. The reaction gases flowing through the collecting tubes are fed to the power generation area of ​​each unit cell via the gas flow paths arranged in each unit cell. Unit cell 11 can be a fuel cell other than the polymer electrolyte fuel cell.

[0024] Collecting pipes such as a hydrogen supply collecting pipe 80, a hydrogen discharge collecting pipe 81, an air supply collecting pipe 82, an air discharge collecting pipe 83, a coolant supply collecting pipe 84 and a coolant discharge collecting pipe 85 are arranged.

[0025] The boost converter 20 is housed in the converter housing 50. The converter housing 50 is made of a high-rigidity material, such as a metal alloy. The converter housing 50 comprises a bottom wall 53 and side walls 54 to 57. An opening through which the busbars 60 and 61 pass faces the bottom wall 53 of the converter housing 50. The side walls 54 to 57 of the converter housing 50 are bolted to the flange 42, the bottom wall 43, and the side walls 46 and 47 of the stack housing 40. The fuel cell stack 10 and the boost converter 20 are housed in an enclosure consisting of the stack housing 40, the converter housing 50, and the end plate 16, which are rigidly mounted and provide external insulation for the fuel cell stack 10 and the boost converter 20.

[0026] The side wall 44 of the side walls 44 to 47 of the stack housing 40 is located between the fuel cell stack 10 and the boost converter 20. The side wall 44 has an opening 48 that allows the busbars 60 and 61 to be connected to the terminals 13a and 13b. That is, the busbars 60 and 61 are connected to the terminals 13a and 13b through the opening 48. The side wall 44 serves as a fastening element to maintain a pressure load on the cell stack 12. The side wall 45 is located on the side of the side wall 44 opposite the fuel cell stack 10. That is, the side wall 45 and the side wall 44 sandwich the fuel cell stack 10 in the Y-direction perpendicular to the X-direction. The side walls 46 and 47, which intersect the side walls 44 and 45, are connected to the flange 42, the bottom wall 43 and the side wall 45.The side walls 45 to 47, which are not provided with an opening, cover the entire fuel cell stack 10 housed in the stacking housing 40.

[0027] The boost converter 20 comprises an inductor 21, a current sensor 22, an intelligent power module (IPM) 23, a capacitor 24, terminal blocks 25 and 26, and conductive elements 31 to 35, such as busbars or cables. The current sensor 22, the IPM 23, and the capacitor 24 are mounted on a circuit board 27. An outer circumferential surface of one coil of the inductor 21 is in contact with a cooling tank 29 via a heat dissipation plate 28. Thus, the boost converter 20 can include the circuit board 27, the heat dissipation plate 28, and the cooling tank 29 as components. The cooling medium for maintaining the temperature of the cooling tank 29 within a predefined temperature range circulates within the cooling tank 29. This cools the inductor 21. Instead of the heat dissipation plate 28, a heat-dissipating resin material with insulating properties can be applied or filled between the choke coil 21 and the cooling tank 29.The IPM 23 incorporates a coolant path 30 through which the cooling medium flows. This cools the IPM 23. The boost converter 20 may contain a temperature sensor.

[0028] The choke coil 21 is electrically connected to the current sensor 22 via the conductive element 32. The current sensor 22 is electrically connected to the IPM 23 via the conductive element 33. The IPM 23 is electrically connected to the capacitor 24 via the conductive element 34. The conductive element 31, which is electrically connected to the choke coil 21, is attached to the terminal block 26. The conductive element 35, which is electrically connected to the capacitor 24, is attached to the terminal block 25. The conductive elements 31 to 35 are made of a metal with low specific electrical resistance, such as copper, aluminum, or an alloy containing these metals.

[0029] One end of busbar 60 is electrically connected by a screw to the protruding section 17a of terminal 13a of the fuel cell stack 10. The other end of busbar 60 is electrically connected by a screw 72 to the conductive element 35 on terminal strip 25. One end of busbar 61 is electrically connected by a screw to the protruding section 17b of terminal 13b of the fuel cell stack 10. The other end is electrically connected by a screw 72 to the conductive element 31 on terminal strip 26. Busbars 60 and 61 are made of a metal with low electrical resistance, such as copper, aluminum, or an alloy containing these metals. Busbars 60 and 61 are located in the housing that includes the stack housing 40 and the converter housing 50. The fuel cell stack 10 is electrically connected to the boost converter 20 via busbars 60 and 61.

[0030] The boost converter 20 amplifies or increases the output power of the fuel cell stack 10. The amplified electrical power is extracted via an opening 58 in the side wall 56 of the converter housing 50. That is, the opening 58 is designed for connecting an external device to an output terminal of the boost converter 20.

[0031] Fig. Figure 3 is a view showing a circuit configuration of the fuel cell unit of the first embodiment. As in Fig. As shown in Figure 3, the boost converter 20 comprises the inductors 21a and 21b, current sensors 22a and 22b, an IPM 23a with a switching element 36a and a diode 37a, an IPM 23b with a switching element 36b and a diode 37b, and the capacitor 24. The inductor 21a, the current sensor 22a, and the diode 37a are connected in series. The inductor 21b, the current sensor 22b, and the diode 37b are also connected in series. These components connected in series are connected in parallel with each other. Such a parallel connection reduces the electrical current flowing through the inductors 21a and 21b and the IPMs 23a and 23b, respectively, thereby suppressing heat generation. The circuit does not necessarily have to be a parallel connection.

[0032] Current sensors 22a and 22b are connected to inductors 21a and 21b on the upstream and downstream sides, respectively. Switching elements 36a and 36b are controlled to open and close based on the values ​​detected by current sensors 22a and 22b, thereby increasing the output voltage of the fuel cell stack 10. Controlling the duty cycle of switching elements 36a and 36b controls the boost ratio of the output voltage to the input voltage in the boost converter 20, resulting in a substantially uniform current flowing through inductors 21a and 21b.

[0033] The boost converter 20 increases or amplifies the output voltage of the fuel cell stack 10 and outputs the increased voltage to an external device 86, which is connected to the output terminal of the boost converter 20 via the opening 58 of the converter housing 50. The external device 86 is, for example, an inverter for a motor that drives a vehicle, an inverter for an auxiliary device, such as an air compressor or a cooling water pump, for driving a fuel cell, an inverter for an auxiliary device for air conditioning a vehicle, or the like.

[0034] As in the Fig. 1 and Fig. As shown in Figure 2, the side wall 45 of the stack housing 40 is perpendicular to the bottom wall 43. That is, an angle θ1 between the side wall 45 and the bottom wall 43 on the fuel cell stack 10 side is 90 degrees. On the other side, the side wall 44 is inclined relative to the bottom wall 43. For example, an angle θ2 between the side wall 44 and the bottom wall 43 on the fuel cell stack 10 side is approximately 96 degrees, which is greater than 90 degrees. In other words, assuming that the side wall 44 extends to the end plate 16, an angle θ3 between the side wall 44 and the end plate 16 on the fuel cell stack 10 side is approximately 84 degrees. As described above, the angle θ2 is larger than the angle θ1, and the side wall 44 is inclined with respect to the bottom wall 43 such that a distance H between the side wall 44 and the side wall 45 in the Y direction is greater on the side of the flange 42 than on the side of the bottom wall 43.The side walls 46 and 47 are also inclined relative to the bottom wall 43. For example, the angle between the side wall 46 and the bottom wall 43 on the side of the fuel cell stack 10 is 93 degrees, and the angle between the side wall 47 and the bottom wall 43 on the side of the fuel cell stack 10 is 93 degrees.

[0035] With regard to connection 13b of connections 13a and 13b, which is located on the side of the bottom wall 43 of the stacking housing 40, the projecting section 17b extends into the opening 48 arranged in the side wall 44 of the stacking housing 40 and overlaps the side wall 44 in the Z-direction perpendicular to the X-direction and the Y-direction. Depending on the angle of inclination of the side wall 44, the projecting section 17b of connection 13b can project from the surface of the side wall 44 on the side of the booster 20 in the direction of the booster 20.

[0036] In contrast, with respect to the connection 13a, which is located on the side of the flange 42 of the stack housing 40, the projecting section 17a, which does not extend into the opening 48, is arranged on the side of the fuel cell stack 10 with respect to the side wall 44. Depending on the angle of inclination of the side wall 44, the projecting section 17a of the connection 13a may extend into the opening 48.

[0037] The Fig. Figures 4A to 4D are views illustrating a method for manufacturing the fuel cell unit of the first embodiment. The stacking housing 40 is constructed as shown in Fig. The stacking housing 40 is prepared as shown in Figure 4A. It is formed by removing a mold from the flange 42 using a casting or die-casting process. Such a method for manufacturing the stacking housing 40 reduces production costs.

[0038] The insulator 14a, the connector 13a, the cell stack 12, the connector 13b, the insulator 14b, the pressure plate 15 and the spring 70 are stacked on the end plate 16. These stacked elements are then, as shown in Fig. As shown in Figure 4B, the end plate 16 is received in the stacking housing 40 through the opening 41. The end plate 16 is then attached to the flange 42 of the stacking housing 40 with the screw 71.

[0039] As in Fig. As shown in Figure 4C, one end of the busbar 60 is fastened with a screw to the protruding section 17a of terminal 13a. One end of the busbar 61 is fastened with a screw to the protruding section 17b of terminal 13b.

[0040] As in Fig. As shown in 4D, the converter housing 50, in which the boost converter 20 is housed, is attached to the stacking housing 40. The other end of the busbar 60 is then connected through an opening 59 located in the side wall 54 of the converter housing 50 (see ). Fig. 2) is attached to the conductive element 35 of the boost converter 20 with screw 72. The other end of the busbar 61 is attached to the conductive element 31 of the boost converter 20 with screw 72 through the opening 59 located in the side wall 55 of the converter housing 50 (see Fig. 2) After the busbars 60 and 61 are each attached to the conductive elements 31 and 35, the openings 59 are closed with covers or similar.

[0041] Fig. Figure 5 is a cross-sectional view showing a fuel cell unit according to a first comparative example. As in Fig. As shown in Figure 5, in a fuel cell unit 1000 according to the first comparative example, the side wall 44 of the stack housing 40 is perpendicular to the bottom wall 43. Although not shown, the side walls 46 and 47 are also perpendicular to the bottom wall 43. The projecting section 17b of the connection 13b, which does not extend into the opening 48 arranged in the side wall 44, is located on the side of the fuel cell stack 10 with respect to the side wall 44. The other components are the same as those of the fuel cell unit 100 of the first embodiment, and their description is omitted.

[0042] In the first comparative example, the preceding sections 17a and 17b of the connections 13a and 13b are located on the side of the fuel cell stack 10 with respect to the side wall 44. The reason for this is that the in Fig. Step 4B, i.e., the step to receive the stacked elements of the cell stack 12, the terminals 13a and 13b and the like, which are stacked on the end plate 16, is to be facilitated in the stack housing 40 through the opening 41.

[0043] According to the first comparative example, all side walls 44 to 47 of the stacking housing 40 are perpendicular to the bottom wall 43. In this example, when manufacturing the stacking housing 40 by a casting or die-casting process, it is difficult to remove the mold from the flange 42.

[0044] Fig. Figure 6 is a cross-sectional view showing a fuel cell unit according to a second comparison example. As in Fig. As shown in Figure 6, in a fuel cell unit 1100 according to the second comparative example, the side walls 44 and 45 of the stack housing 40 are inclined at the same angle to the bottom wall 43. That is, angle θ1 and angle θ2 are equal. The projecting section 17b of the connection 13b, which does not extend into the opening 48 arranged in the side wall 44, is located on the side of the fuel cell stack 10 with respect to the side wall 44. The other components are the same as those of the fuel cell unit 100 of the first embodiment, and their description is omitted.

[0045] According to the second comparative example, the side walls 44 and 45 of the stacking housing 40 are inclined at the same angle with respect to the bottom wall 43. Therefore, when manufacturing the stacking housing 40 by casting or die casting, a demolding angle defined by the side walls 44 and 45 facilitates the removal of the mold from the flange 42. This improves manufacturability. To facilitate removal of the mold from the flange 42, the side walls 44 and 45 are generally inclined at the same angle to the bottom wall 43. Furthermore, as in the first comparative example, to accommodate the stacked elements of the cell stack 12, the connections 13a and 13b, and the like, which are stacked on the end plate 16, the projecting sections 17a and 17b are arranged in the stacking housing 40 through the opening 41 on the side of the fuel cell stack 10 with respect to the side wall 44.However, this increases the size of the fuel cell unit 1100 in the second comparison example.

[0046] According to the first embodiment, as in the Fig. 1 and Fig. As shown in Figure 2, the side wall 44 is inclined relative to the bottom wall 43 such that the distance between the side walls 44 and 45 is greater on the flange side 42 than on the bottom wall side 43. When the stacking housing 40 is manufactured by a casting or die-casting process, the mold between the side walls 44 and 45 is removed through the opening 41. This improves the manufacturability of the stacking housing 40. Furthermore, the distance between the side walls 44 and 45 is greater on the flange side 42 than on the bottom wall side 43, which facilitates the insertion of the fuel cell stack 10, which is arranged on the end plate 16, into the stacking housing 40 through its opening 41. As shown in Figure 2, the side wall 44 is inclined relative to the bottom wall 43 such that the distance between the side walls 44 and 45 is greater on the flange side 42 than on the bottom wall side 43. Fig. As shown in Figure 1, the angle θ2 between the side wall 44 and the bottom wall 43 on the side of the fuel cell stack 10 is larger than the angle θ1 between the side wall 45 and the bottom wall 43 on the side of the fuel cell stack 10. Since the inclination of the side wall 45 relative to the bottom wall 43 is thus smaller than the inclination of the side wall 44 relative to the bottom wall 43, the enlargement of the fuel cell unit 100 caused by the side wall 45 is suppressed. As shown in the Fig. 1 and Fig. As further shown in Figure 2, the side wall 44 of the stacking housing 40 overlaps the preceding section 17b of the connection 13b in the Z direction. In the case of the Fig. In the manufacturing process shown in Figure 4, when the stacking housing 40 is slid into the stacking housing 40 to receive the fuel cell stack 10, the protruding section 17b of the connection 13b must not interfere with the side wall 44 of the stacking housing 40. Since the side wall 44 of the stacking housing 40 is provided with the opening 48, the protruding section 17b prevents engagement with the side wall 44 of the stacking housing 40 in the Z-direction, even if the side wall 44 of the stacking housing 40 overlaps the protruding section 17b of the connection 13b in the Z-direction.Even in a case where the side wall 44 is inclined relative to the bottom wall 43, the side wall 44 overlaps the projecting section 17b of the terminal 13b in the Z-direction, thus the increased size of the fuel cell unit 100 in the Y-direction due to the inclination of the side wall 44 overlaps the increased size of the fuel cell unit 100 in the Y-direction due to the projecting section 17b of the terminal 13b. This suppresses an increase in the size of the stack housing 40 in the Y-direction, which in turn suppresses an increase in the size of the fuel cell unit 100. Additionally, a nut is used to fasten the busbar 61 to the projecting section 17b of the terminal 13b, which requires a predetermined gap between the nut and the cell stack 12. It is therefore difficult to reduce the height of the projecting section 17b of the terminal 13b.This suppresses the increase in size of the fuel cell unit 100, thereby improving the mountability of the fuel cell unit 100 on a vehicle or similar.

[0047] As in Fig. As shown in Figure 2, the Y-direction side wall 56 of the converter housing 50 is provided with the opening 58 for the electrical connection of an external device to the boost converter 20. To allow a large current to flow to the external device, a large-dimensioned plug is typically connected through the opening 58, and the converter housing 50 tends to be long in the Y direction. Reducing the length of the stack housing 40 in the Y direction can counteract an increase in the height of the fuel cell unit 100 in the Y direction. To further prevent an increase in the height of the fuel cell unit 100 in the Y direction, the angle θ2 between the side wall 44 and the bottom wall 43 can be greater than the angle θ1 between the side wall 45 and the bottom wall 43, and the side wall 44 can overlap the protruding section 17b of the connector 13b in the Z direction.

[0048] As in Fig. As shown in Figure 1, the flange 42 of the stacking housing 40 comprises: a flat surface 75 to which the end plate 16 is attached; and an outer circumferential surface 76 that extends continuously from the end of the flat surface 75. The outer circumferential surface 76 of the flange 42 is flat from end to end in the X-direction. The converter housing 50 is attached to the outer circumferential surface 76 of the flange 42. If, for example, a step is formed on the outer circumferential surface 76 of the flange 42, and if the converter housing 50 is attached to an upper or lower face of the step on the outer circumferential surface 76, the area in which the converter housing 50 is attached could be reduced, and it could be difficult to accommodate the components of the boost converter 20 within the converter housing 50.However, since the outer circumferential surface 76 of the flange 42 is flat from one end to the other in the X-direction, the converter housing 50 is attached to the stacking housing 40 using the entire length of the flange 42 in the X-direction. In this way, it is possible to accommodate many parts and large parts in the converter housing 50.

[0049] As in Fig. As shown in Figure 1, the maximum height of the stack housing 40 in the Y-direction can be the sum of the length L1 of the opening 41 in the Y-direction, the length L2 of the flange 42 located on one side of the opening 41 in the Y-direction, and the length L2 of the flange 42 located on the other side of the opening 41 in the Y-direction. In other words, the highest point of the stack housing 40 in the Y-direction can be located at the flange 42. Therefore, the height of the stack housing 40 in the Y-direction is the minimum necessary height, and the enlargement of the stack housing 40 is suppressed, thereby suppressing the enlargement of the fuel cell unit 100. Since suppressing the increase in the size of the stack housing 40 also suppresses an increase in the size of the manufacturing equipment for producing the stack housing 40, an increase in equipment costs is also suppressed.In the case of the connection of the end plate 16 to the flange 42 via a gasket, the top surface of the flange 42 in the Y-direction is approximately the sum of the length of the top surface of a groove for the gasket in the Y-direction, the length of the flat surfaces on both sides across the groove in the Y-direction, and the length of the bolt in the Y-direction. In the case of the use of a liquid gasket, the top surface of the flange 42 in the Y-direction is approximately the sum of the length in the Y-direction of a flat surface to which the liquid gasket is applied and the length of the bolt in the Y-direction.

[0050] As in Fig. As shown in Figure 1, the length L1 of the opening 41 in the Y-direction is greater than the length L3 of the fuel cell stack 10 in the Y-direction. Thus, the fuel cell stack 10, in which the cell stack 12, the terminals 13a and 13b, and the like are stacked on the end plate 16, is housed through the opening 41 in the stack housing 40.

[0051] Fig. Figure 7 is a cross-sectional view of the stacking housing. Fig. Figure 7 shows a cross-section at the opening 48, which is arranged in the side wall 44. As in Fig. As shown in Figure 7, the distance H1 between the side wall 44 and the side wall 45 at the end of the opening 48 on the side of the flange 42 in the Y direction is greater than the length L3 (see Figure 7). Fig. 1) of the fuel cell stack 10 in the Y-direction. Therefore, the fuel cell stack 10, arranged at the end plate 16, is mounted linearly through the opening 41 in the stack housing 40. This makes it possible to easily accommodate the fuel cell stack 10 in the stack housing 40. [Second embodiment]

[0052] Fig. Figure 8 is a cross-sectional view of a fuel cell unit according to a second embodiment. As in Fig. As shown in Figure 8, in a fuel cell unit 200 of the second embodiment, the side wall 45 is inclined relative to the bottom wall 43 in addition to the side wall 44. For example, the angle θ1 between the side wall 45 and the bottom wall 43 on the side of the fuel cell stack 10 is greater than 90 degrees. For example, the angle θ1 is approximately 92 degrees. In other words, assuming that the side wall 45 extends to the end plate 16, the angle θ4 between the side wall 45 and the end plate 16 on the side of the fuel cell stack 10 is approximately 88 degrees. An angle between the side wall 46 and the bottom wall 43 on the side of the fuel cell stack 10 is approximately 93 degrees. An angle between the side wall 47 and the bottom wall 43 on the side of the fuel cell stack 10 is approximately 93 degrees. The angle θ2 between the side wall 44 and the bottom wall 43 on the side of the fuel cell stack 10 is approximately 94 degrees.In other words, assuming that the side wall 44 extends to the end plate 16, the angle θ3 between the side wall 44 and the end plate 16 on the side of the fuel cell stack 10 is approximately 86 degrees. The other components are the same as in the first embodiment, and their description is omitted.

[0053] The first embodiment describes, by way of example, the side wall 45 of the stacking housing 40 perpendicular to the bottom wall 43. However, it is not limited to this. As long as the angle θ2 between the side wall 44 and the bottom wall 43 on the fuel cell stack 10 side is greater than the angle θ1 between the side wall 45 and the bottom wall 43 on the fuel cell stack 10 side, the side wall 45 can be inclined relative to the bottom wall 43, as described in the second embodiment. If both side walls 44 and 45 are inclined relative to the bottom wall 43, this further improves the manufacturability of the stacking housing 40. On the other hand, from the perspective of suppressing an increase in the size (height) of the stacking housing 40, the angle θ1 between the side wall 45 and the bottom wall 43 on the fuel cell stack 10 side can be a right angle.The right angle includes an angle that deviates from 90 degrees, caused by a manufacturing defect.

[0054] As long as the size of the stacking housing 40 on the side of the flange 42 in the Y direction is larger than that of the stacking housing 40 on the side of the bottom wall 43 in the Y direction, and if the fuel cell stack 10 arranged at the end plate 16 is received through the opening 41 in the stacking housing 40, the angle θ1 between the side wall 45 and the bottom wall 43 can be less than 90 degrees. [Third embodiment]

[0055] Fig. Figure 9A is a cross-sectional view of a fuel cell unit according to a third embodiment. Fig. Figure 9B is a cross-sectional view of some components of a boost converter housed in a converter chassis. Regarding a [missing information] in the Fig. 9A and Fig. In the fuel cell unit 300 shown in Figure 9B according to the third embodiment, the choke coil 21, the current sensor 22, the IPM 23, and the capacitor 24 of the boost converter 20 each have end sections on the side wall 44 of the stack housing 40. A distance L1 is defined between the bottom wall 53 of the converter housing 50 and the end section of the choke coil 21. A distance L2 is defined between the bottom wall 53 and the end section of the current sensor 22. A distance L3 is defined between the bottom wall 53 and the end section of the IPM 23. A distance L4 is defined between the bottom wall 53 and the end section of the capacitor 24. The distances L1 to L4 are different from each other.For example, the distance L1 between the end section of the choke coil 21 on the side wall 44 and the bottom wall 53 of the converter housing 50 is greater than the distance L2 between the end section of the current sensor 22 on the side wall 44 and the bottom wall 53 of the converter housing 50. The distance L2 between the end section of the current sensor 22 on the side wall 44 and the bottom wall 53 of the converter housing 50 is greater than the distance L3 between the end section of the IPM 23 on the side wall 44 and the bottom wall 53 of the converter housing 50. The distance L3 between the end section of the IPM 23 on the side wall 44 and the bottom wall 53 of the converter housing 50 is greater than the distance L4 between the end section of the capacitor 24 on the side wall 44 and the bottom wall 53 of the converter housing 50.This means that, with respect to the distance between the end section on the side wall 44 of the stack housing 40 and the bottom wall 53 of the converter housing 50, the distance L1 with respect to the choke coil 21 is the greatest. The distance L1 with respect to the choke coil 21, the distance L2 with respect to the current sensor 22, the distance L3 with respect to the IPM 23, and the distance L4 with respect to the capacitor 24 decrease in this order.

[0056] The choke coil 21 is located on the side of the bottom wall 43 with respect to a virtual area 73, which is situated midway between the flange 42 and the bottom wall 43 of the stack housing 40 in the X direction. For example, the capacitor 24, the IPM 23, the current sensor 22, and the choke coil 21 of the boost converter 20 are arranged from the side of the flange 42 in descending order of distance between the end section on the side of the side wall 44 of the stack housing 40 and the bottom wall 53 of the converter housing 50. Of the choke coil 21, the current sensor 22, the IPM 23 and the capacitor 24 of the boost converter 20, the choke coil 21, which has the longest distance between the end section on the side of the side wall 44 of the stack housing 40 and the bottom wall 53 of the converter housing 50, is located closest to the side of the bottom wall 43 of the stack housing 40.

[0057] Furthermore, the choke coil 21 projects towards the side wall 44 beyond a virtual surface 74. The virtual surface 74 extends parallel to the X-direction and passes through a point where the surface of the side wall 44 of the stack housing 40 on the side of the boost converter 20 is connected to the flange 42. In other words, the end section of the choke coil 21 on the side of the side wall 44 of the stack housing 40 overlaps the side wall 44 in the X-direction. The remaining components are the same as in the first embodiment, and their description is omitted.

[0058] According to the third embodiment, the choke coil 21, whose end section is located furthest from the bottom wall 53 of the converter housing 50 on the side of the side wall 44 of the stack housing 40, is positioned on the side of the bottom wall 43 with respect to the midpoint between the flange 42 and the bottom wall 43 in the X direction. This ensures a certain distance between the end section of the choke coil 21 and the side wall 44 of the stack housing 40, and effectively utilizes the space formed by the inclination of the side wall 44 of the stack housing 40 with respect to the bottom wall 43. This suppresses the increase in size (high profile) of the fuel cell unit 300.The choke coil 21, whose end section is furthest from the bottom wall 53 of the converter housing 50 on the side of the side wall 44 of the stack housing 40, can be located within one of three areas on the side of the bottom wall 43, into which a space between the flange 42 and the bottom wall 43 of the stack housing 40 is evenly divided in the X direction. The choke coil 21 can be located within one of four areas closest to the bottom wall 43, into which the space is evenly divided.

[0059] The reason for ensuring a certain space between the choke coil 21 and the side wall 44 of the stacking housing 40 is to prevent an electrical short circuit between the choke coil 21 and the side wall 44. This space can range from approximately 3 mm to approximately 7 mm. Additionally, a certain degree of clearance can be maintained between each component except the choke coil 21 and the side wall 44 to prevent an electrical short circuit between the components and the side wall 44. Furthermore, each component has a manufacturing tolerance. Thus, a certain clearance is maintained between the boost converter 20 component and the side wall 44, preventing interference between the boost converter 20 and the side wall 44 when the converter housing 50 is assembled with the stacking housing 40.

[0060] As in Fig. As shown in Figure 9A, the end section of the choke coil 21 on the side wall 44 can overlap the side wall 44 of the stack housing 40 in the X-direction. Therefore, the space formed by the inclination of the side wall 44 relative to the bottom wall 43 of the stack housing 40 is effectively utilized, and the increase in size (high profile) of the fuel cell unit 300 is suppressed. The third embodiment describes, by way of example, the choke coil 21 whose end section overlaps the side wall 44 of the stack housing 40 on the side furthest from the bottom wall 53 of the converter housing 50 in the X-direction. However, it is not limited to this. The end section on the side wall 44 of other components of the boost converter 20 can also overlap the side wall 44 in the X-direction.

[0061] As in the Fig. 9A and Fig. As shown in Figure 9B, the boost converter 20 comprises: the inductor 21, the end section of which is located furthest from the bottom wall 53 of the converter housing 50 on the side of the side wall 44 of the stack housing 40; the current sensor 22, wherein the distance between its end section on the side of the side wall 44 and the bottom wall 53 is less than the distance between the end section of the inductor 21 on the side of the side wall 44 and the bottom wall 53; and the IPM 23, wherein the distance between its end section on the side of the side wall 44 and the bottom wall 53 is less than the distance between the end section of the current sensor 22 on the side of the side wall 44 and the bottom wall 53. The IPM 23, the current sensor 22, and the inductor 21 can be arranged in this order from the side of the flange 42 of the stack housing 40. In this way, the space between the upconverter 20 and the side wall 44 of the stacking housing 40 is used effectively.

[0062] In at least one of the components of the upconverter 20, its end section can be inclined on the side of the side wall 44 along the side wall 44. [Fourth embodiment]

[0063] Fig. Figure 10 is a cross-sectional view of a fuel cell unit according to a fourth embodiment. As in Fig.As shown in Figure 10, in a fuel cell unit 400 of the fourth embodiment, the positions of the choke coil 21, the current sensor 22, the IPM 23, and the capacitor 24 of the boost converter 20 differ from those of the first to third embodiments. In the fourth embodiment, the choke coil 21, the current sensor 22, the IPM 23, and the capacitor 24 are arranged in that order from the flange 42 of the stack housing 40 to the bottom wall 43. The capacitor 24 is larger compared to the first to third embodiments. Compared to the components of the boost converter 20, the distance between the end section of the capacitor 24 on the side wall 44 of the stack housing 40 and the bottom wall 53 of the converter housing 50 is the longest. The capacitor 24 is located on the side of the bottom wall 43 with respect to the virtual area 73, which is located in the middle between the flange 42 and the bottom wall 43 of the stack housing 40.Furthermore, the capacitor 24 projects beyond the virtual surface 74 in the direction of the side wall 44. This surface extends parallel to the X-direction and passes through a point where the surface of the side wall 44 of the stack housing 40 on the side of the boost converter 20 is connected to the flange 42. In other words, the end section of the capacitor 24 on the side wall 44 of the stack housing 40 overlaps the side wall 44 in the X-direction. The remaining components are the same as in the first embodiment, and their description is omitted.

[0064] In the fourth embodiment, the component of the boost converter 20 whose end section is furthest from the bottom wall 53 of the converter housing 50 on the side wall 44 of the stack housing 40 is the capacitor 24. In this case, the capacitor 24 is large. The amount of heat generated by the capacitor 24 correlates with its capacitance. The amount of heat decreases with increasing size of the capacitor 24. Therefore, according to the fourth embodiment, the amount of heat generated by the capacitor 24 is reduced.

[0065] As in the second embodiment, in the third and fourth embodiments the side wall 45 of the stacking housing 40 can also be inclined with respect to the bottom wall 43.

[0066] In the first to fourth embodiments, the fuel cell unit can be mounted on the vehicle or the like in a state where the side of the side wall 45 of the stacking housing 40 points downwards in the direction of gravity. However, the fuel cell unit can also be mounted on the vehicle or the like in a different orientation. For example, the fuel cell unit can be mounted on the vehicle or the like in a state where the end plate 16 points downwards in the direction of gravity. The fuel cell unit can be mounted on the vehicle or the like in a state where the side of the bottom wall 53 of the converter housing 50 points downwards in the direction of gravity.

[0067] The first to fourth embodiments describe the boost converter 20 as an example of a power converter that converts the output power of the fuel cell stack 10. However, the power converter is not limited to the boost converter 20. The power converter can, for example, be a buck converter, a boost / blow converter for performing both boost and buck conversions, or an inverter for converting direct current power to alternating current power.

[0068] Although some embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, but can be varied or modified within the scope of the claimed invention.

Claims

[1] Fuel cell unit (100, 200, 300, 400), comprising: a fuel cell stack (10) with: a cell stack (12) in which unit cells are stacked in a first direction; a first connection (13a) which is accordingly arranged at a first end of the cell stack (12) in the first direction; and a second terminal (13b) which is located at a second end of the cell stack (12) in the first direction; an end plate (16) which is located on a side of the cell stack (12) opposite the first terminal (13a); a power converter (20) that converts an output power of the fuel cell stack (10); a stacking housing (40) that accommodates the fuel cell stack (10); a power converter housing (50) that accommodates the power converter (20) and is attached to the stacking housing (40); a first busbar (60) that electrically connects the first terminal (13a) and the power transformer (20) in the stacking housing (40) and the power transformer housing (50); and a second busbar (61) which electrically connects the second terminal (13b) and the power transformer (20) in the stacking housing (40) and the power transformer housing (50), where the first connection (13a) comprises a first projecting section (17a) that extends from the cell stack (12) and is connected to the first busbar (60), the second connection (13b) comprises a second projecting section (17b) that extends from the cell stack (12) and is connected to the second busbar (61), the stacking housing (40) comprises: a frame-shaped flange (42) which defines a first opening (41) on its inside and is attached to the end plate (16) so that the fuel cell stack (10) is housed in the stack housing (40); a first bottom wall (43), wherein the fuel cell stack (10) is arranged sandwich-like between the first bottom wall (43) and the end plate (16) in the first direction; a first side wall (44) arranged between the fuel cell stack (10) and the power converter (20), connected between the flange (42) and the first bottom wall (43), and comprising a second opening (48) that allows the first and second busbars (60, 61) to be connected accordingly to the first and second terminals (13a, 13b); and a second side wall (45) connected between the flange (42) and the first bottom wall (43), wherein the fuel cell stack (10) is arranged between the first side wall (44) and the second side wall (45) in a second direction perpendicular to the first direction, the first side wall (44) is inclined in relation to the first bottom wall (43) such that the distance between the first side wall (44) and the second side wall (45) on one side of the flange (42) is greater than on one side of the first bottom wall (43), an angle between the first side wall (44) and the first bottom wall (43) on one side of the fuel cell stack (10) is greater than an angle between the second side wall (45) and the first bottom wall (43) on one side of the fuel cell stack (10), and the first side wall (44) overlaps the second projecting section (17b) of the second connection (13b) in a third direction perpendicular to the first direction and the second direction. [2] Fuel cell unit (100, 300, 400) according to claim 1, wherein the angle between the second side wall (45) and the first bottom wall (43) on the side of the fuel cell stack (10) is a right angle. [3] Fuel cell unit (300, 400) according to claim 1 or 2, wherein the power converter housing (50) comprises a second bottom wall (53), wherein the power converter (20) is arranged between the second bottom wall (53) and the first side wall (44) in the second direction, Components (21, 22, 23, 24) of the power converter (20) comprise a first component (21, 24), of the components, an end section of the first component (21, 24) is furthest away from the second bottom wall (53) on one side of the first side wall (44), the first component (21, 24) is arranged with respect to a center between the flange (42) and the first bottom wall (43) in the first direction on one side of the first bottom wall (43). [4] Fuel cell unit (300) according to claim 3, wherein the components (21, 22, 23, 24) comprise the first component (21), a second component (22) and a third component (23), a distance between the second bottom wall (53) and an end section of the second component (22) on one side of the first side wall (44) is smaller than a distance between the second bottom wall (53) and the end section of the first component (21), a distance between the second bottom wall (53) and an end section of the third component (23) on one side of the first side wall (44) is smaller than the distance between the second bottom wall (53) and the end section of the second component (22), and the third component (23), the second component (22) and the first component (21) are arranged in this order from the flange (42). [5] Fuel cell unit (300, 400) according to one of claims 1 to 4, wherein a component (21, 24) of the components (21, 22, 23, 24) of the power converter (20) comprises an end section on a first side wall (44) which overlaps the first side wall (44) in the first direction. [6] Fuel cell unit (100) according to any one of claims 1 to 5, wherein the power converter housing (50) includes a third side wall (56) along the second direction, and the third side wall (56) includes an opening (58) which allows the electrical connection of an external device to the power converter (20). [7] Fuel cell unit (100, 200, 300, 400) according to any one of claims 1 to 6, wherein the flange (42) comprises: a flat surface to which the end plate (16) is attached, and an outer circumferential surface that is continuous from an edge of the flat surface, the outer circumferential surface of the flange (42) is flat from one end to the other in the first direction, and the power converter housing (50) is attached to the outer circumferential surface of the flange (42). [8] Fuel cell unit (100, 200, 300, 400) according to any one of claims 1 to 7, wherein the height of the stack housing (40) in the second direction is at its maximum at a position where the flange (42) is located. [9] Fuel cell unit (100, 200, 300, 400) according to any one of claims 1 to 8, wherein a length of the first opening (41) in the second direction is greater than a length of the fuel cell stack (10) in the second direction. [10] Fuel cell unit (100, 200, 300, 400) according to any one of claims 1 to 9, wherein a distance between the first side wall (44) and the second side wall (45) at one end of the second opening (48) on one side of the flange (42) in the second direction is greater than a length of the fuel cell stack (10) in the second direction.

Images