PIPE STRUCTURE

Abstract

A tube assembly (3) mounted at one end in a cell stacking direction of a cell stack (2) in a fuel cell (1) and used to supply a coolant to the cell stack (2) and discharge a coolant from the cell stack (2), the tube assembly (3) comprising: an end plate (4) having an opposite surface (12) facing the end in the cell stacking direction of the cell stack (2); a recess (14) open in the opposite surface (12) and forming a flow path in which the coolant flows; a rib (16) projecting from a bottom surface (14a) of the recess (14) to an opening position of the recess (14) on the opposite surface (12); and a plastic layer (13) formed to cover the opposing surface (12), the recess (14) and the rib (16), wherein portions of the plastic layer (13) covering the opposing surface (12) and a distal end surface in a projecting direction of the rib (16) are in contact with the end in the cell stacking direction of the cell stack (2), wherein the tube structure (3) is characterized in that the portion of the plastic layer (13) covering the distal end surface in the protruding direction of the rib (16) has a cooling channel (21) which causes the coolant to flow in the flow path formed by the recess (14) to a space between that portion of the plastic layer (13) and a contact surface of the end in the cell stacking direction of the cell stack (2), wherein the cooling channel (21) in the portion of the plastic layer (13) covering the distal end surface in a projecting direction of the rib (16) comprises: a relief portion (22) open to the end in the cell stacking direction of the cell stack (2), and a plurality of cutout sections (23) enabling the relief section (22) to communicate with the flow path.

Description

BACKGROUND

[0001] The present invention relates to a pipe structure.

[0002] As disclosed in Japanese Patent Application Laid-Open No. 2016-91845 A, a fuel cell mounted on a vehicle such as an automobile is equipped with a piping structure that causes a fluid, specifically a fuel gas, oxidizing gas, and coolant, to flow through the cell stack of the fuel cell. The fuel cell is cooled by the coolant supplied to and discharged from the cell stack via the piping structure, while power is generated using the fuel gas, and oxidizing gas is supplied to and discharged from the cell stack via the piping structure.

[0003] Such a tube structure includes a metal end plate attached to a fuel cell casing provided to surround the cell stack. The end plate has an opposing surface facing one end of the cell stack in the cell stacking direction, a recess open in the opposing surface and forming a flow path through which a coolant flows, and ribs projecting from the bottom surface of the recess to the opening position of the recess on the opposing surface. Furthermore, the opposing surface, the recess, and the ribs in the end plate are covered by a plastic sheet.

[0004] When the end plate is fixed to the housing, the portion of the plastic sheet covering the opposite surface and the portions of the plastic sheet covering the distal end surfaces in the protruding direction of the ribs are in contact with the end in the cell stacking direction of the cell stack. This causes the cell stack to be pressed in the cell stacking direction by the opposite surface, thus maintaining a favorable cell stacking structure of the same cell stack.

[0005] At this time, the opening of the recess formed on the opposite surface of the end plate is closed by the end in the cell stacking direction of the cell stack, forming a flow path through which coolant flows in the recess. The end in the cell stacking direction of the cell stack is cooled by the coolant flowing in the flow path.

[0006] The fluid in the flow path and the end plate are isolated from each other by a portion of the plastic layer covering the inner surface of the recess and the outer surfaces of the ribs. The end plate and the cell stack are isolated from each other by the portion of the plastic layer covering the opposing surface and the portions of the plastic layer covering the distal end surfaces in the protrusion direction of the ribs.

[0007] The end of the cell stack in the cell stack direction is cooled by the coolant flowing in the flow path in the recess formed in the opposite surface of the end plate. However, the portions of the end that contact the portions of the resin sheet covering the distal end surfaces in the protruding direction of the fins do not readily contact the coolant in the flow path, and therefore cannot be effectively cooled.

[0008] US 2016 / 0 133 953 A1 discloses an end plate for a fuel cell. A front end plate has a coolant flow path in the form of a recess in a facing surface and flow path fin portions located within the recess, protruding from a bottom surface of the recess. A cooling surface covers the recess, the flow path fin portions, and the facing surface. The cooling surface can be formed from plastic. SUMMARY

[0009] Accordingly, it is an object of the present invention to provide a tube structure capable of effectively cooling an end in the cell stacking direction of a cell stack, particularly portions of the end in contact with portions of a resin sheet covering the distal end surfaces in the protruding direction of the fins.

[0010] Measures to solve the problem described above are described below.

[0011] The above-mentioned object is achieved by a pipe structure having the features of claim 1.

[0012] Advantageous further training is the subject of dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows a schematic representation of the manner in which a tube assembly (end plate) is attached to the cell stack of a fuel cell. Fig. 2 shows a schematic plan view of the tube structure of Fig. 1 looking at the cell stack. Fig. 3 shows a cross-sectional view along a line AA of the Fig. 2 shown pipe structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A pipe structure according to an embodiment is described below with reference to the Fig. 1 to 3.

[0014] As this is Fig. 1, a fuel cell 1 has a cell stack 2 and a tube assembly 3 which is connected at one end in the cell stacking direction of the cell stack 2 (the left and right direction in Fig. 1). The tube assembly 3 is used to cause a fluid, specifically hydrogen (fuel gas), air (oxidizing gas), and cooling water (a coolant), to flow through the cell stack 2. The tube assembly 3 has a metal end plate 4 attached to a casing of the fuel cell 1, which is provided to surround the cell stack 2. The cell stack 2 uses the hydrogen and air supplied and discharged through the tube assembly 3 to generate power, and it is cooled by the cooling water supplied and discharged through the tube assembly 3.

[0015] Fig. 2 shows schematically a state of the pipe structure 3 (the end plate 4) from Fig. 1, viewed from the cell stack 2. The end plate 4 is in the shape of a rectangular plate with a pair of long sides and a pair of short sides. The end plate 4 has a fastening portion 5 on the outer periphery that extends along the long sides and the short sides. The end plate 4 is fastened to the housing 1a (see FIG. Fig. 1), for example by means of screws on the fastening section 5. The surface of the fastening section 5 on the side facing the cell stack 2 (the surface on the near side of the drawing of Fig. 2) forms a mounting surface 6 which is brought into contact with the housing 1a and fixed.

[0016] The end plate 4 has holes 7 to 11 in a part (portion) surrounded by the fixing portion 5. The holes 7 to 11 extend through the end plate 4 in the thickness direction (the direction perpendicular to the plane of the drawing of Fig. 2). The holes 7 to 11 form flow paths through which a coolant flows. The holes 7, 8, 10, and 11 are open at an opposite surface 12 of the end plate 4 facing the end in the cell stacking direction of the cell stack 2. Furthermore, the end plate 4 has a recess 14 open at the opposite surface 12 and extending along the opposite surface 12 in the long side direction of the end plate 4. The hole 9 is open in a bottom surface 14a of the recess 14 at one end in the long side direction. The hole 9 and the recess 14 form a flow path through which the coolant flows.

[0017] When the fastening section 5 of the end plate 4 is fixed to the housing 1a (see Fig. 1), the flow paths formed by the holes 7, 8, 10, 11 are connected to the cell stack 2. At this time, the opening of the recess 14 formed on the opposite surface 12 is closed by the end in the cell stacking direction of the cell stack 2, and a flow path through which coolant flows is formed in the recess 14. Further, the other end of the flow path in the recess 14 in the long side direction is connected to a channel 15 for cooling water formed in the cell stack 2. In the present example, the cooling water flows out of the channel 15 into the flow path in the recess 14, and thereafter, the cooling water flows into the flow path in the direction in which the recess 14 extends and flows out of the hole 9.Therefore, the recess 14 is formed along the opposite surface 12 so as to extend in the flow direction of the cooling water in the flow path in the recess 14.

[0018] A plurality of ribs 16 protrude from the bottom surface 14a of the recess 14. The ribs 16 are provided at intervals in the direction of the short sides of the end plate 4 and are formed to extend in the same direction as the extending direction of the recess 14. When the fixing portion 5 of the end plate 4 is fixed to the housing 1a (see FIG. Fig. 1), the cell stack 2 is pressed in the cell stacking direction by the opposing surface 12 and the ribs 16, so that a favorable cell stacking structure of the cell stack 2 is maintained. The end plate 4 has a plastic layer 13 covering the inner surfaces of the holes 7 to 11, the opposing surface 12, the recess 14, and the ribs 16. The plastic layer 13 isolates the fluid in the flow paths formed by the holes 7, 8, 10, and 11 from the end plate 4, and isolates the fluid (cooling water) in the flow path formed by the hole 9 and the recess from the end plate 4.

[0019] The plastic layer 13 is described below.

[0020] Fig. 3 shows the end plate 4 and the plastic layer 13 in Fig. 2 as viewed from the direction of arrows AA. As can be seen from the drawing, the ribs 16 protrude from the bottom surface 14a of the recess 14 to the opening position of the recess 14 in the opposing surface 12, and the resin sheet 13 is formed to cover the opposing surface 12, the inner surface of the recess 14, and the outer surface of the ribs 16. When the mounting surface 6 of the fixing portion 5 of the end plate 4 is brought into contact with and fixed to the casing 1a, a portion of the resin sheet 13 covering the opposing surface 12 and portions of the resin sheet 13 covering the distal end surfaces in the protruding direction of the ribs 16 are in contact with the end in the cell stacking direction of the cell stack 2.The end plate 4 and the end in the cell stacking direction of the cell stack 2 are isolated from each other by the portion of the plastic sheet 13 covering the opposite surface 12 and the portions of the plastic sheet 13 covering the distal end surfaces in the projecting direction of the ribs 14.

[0021] The end in the cell stacking direction of the cell stack 2 is cooled by the cooling water flowing in the flow path in the recess 14 formed in the opposite surface 12 of the end plate 4. However, cooling by the cooling water is difficult to perform at the portions of the end in contact with the portions of the resin sheet 13 covering the distal end surfaces in the protruding direction of the ribs 14. Therefore, the portions of the resin sheet 13 covering the distal end surfaces in the protruding direction of the ribs 16 each have a cooling channel 21. The cooling channels 21 cause the cooling water to flow in the flow path formed by the recess 14 to the space between those portions of the resin sheet 13 and a contact surface of the end in the cell stacking direction of the cell stack 2.

[0022] Each cooling channel 21 is provided with a relief portion 22 and cutout portions 23 formed in a portion of the resin sheet 13 covering the distal end surface in the protruding direction of the corresponding rib 16. The relief portion 22 is open to the end in the cell stacking direction of the cell stack 2 and is formed to extend along the rib 16. The cutout portions 23 allow the relief portion 22 to communicate with the flow path. Each relief portion 22 is provided with a plurality of cutout portions 23.

[0023] As this is Fig.As shown in Fig. 2, the lightening portions 22 are provided between a pair of upright walls 24 extending parallel to the ribs 16 in the portions of the resin sheet 13 covering the distal end surfaces in the projecting direction of the ribs 16. The upright walls 24 of each pair are connected to each other by a plurality of reinforcing portions 25 provided at intervals in the extending direction of the ribs 16. The cutout portions 23 are formed in the upright walls 24 such that a plurality of cutout portions 23 communicate with each of the lightening portions 22 divided by the reinforcing portions 25.

[0024] In the present example, in each of the lightening portions 22 divided by the reinforcing portions 25, the cutout portions 23 are formed at the center of the upright walls 24 in the direction in which the ribs 16 extend.

[0025] The operation and advantages of the pipe structure 3 of the present embodiment are described below. (1) After flowing out of the flow path in the recess 14 of the end plate 4 from the channel 15, the cooling water that cools the cell stack 2 flows in the flow path in the direction in which the recess 14 extends and flows out of the hole 9. At this time, the end in the cell stacking direction of the cell stack 2 is cooled by the cooling water. Furthermore, the cooling channels 21 cause the cooling water in the flow path formed in the recess 14 to flow to the space between the portions of the resin sheet 13 covering the distal end surfaces in the protruding direction of the ribs 16 and the contact surface of the end in the cell stacking direction of the cell stack 2. In this way, the cooling water flowing in the cooling channels 21 effectively cools the end in the cell stacking direction of the cell stack 2, ie, the portions of the plastic sheet 13 covering the distal end surfaces in the protruding direction of the fins. (2) The lightening portions 22 forming the cooling channels 21 are formed to open toward the end in the cell stacking direction of the cell stack 2 at the portions of the resin sheet 13 covering the distal end surfaces in the protruding direction of the ribs 16. The portions of the resin sheet 13 covering the distal end surfaces in the protruding direction of the ribs 16 contact the end in the cell stacking direction of the cell stack 2, so that the opening of each lightening portion is closed. The lightening portions 22 communicate with the flow path in the recess 14 through the plurality of cutout portions 23.Since the thus formed cooling channels 21 (the relief portions 22) communicate with the flow path in the recess 14 at a plurality of positions through the cutout portions 23, the cooling water easily flows into the cooling channels 21 from the flow path and also easily flows out of the flow path. (3) The lightening portions 22 are each provided between a pair of upright walls 24 extending parallel to the ribs 16 in the portions of the resin sheet 13 covering the distal end surfaces in the projecting direction of the ribs 16. The upright walls 24 of each pair are connected to each other by a plurality of reinforcing portions 25 provided at intervals in the extending direction of the ribs 16. Therefore, when the portions of the resin sheet 13 covering the distal end surfaces in the projecting direction of the ribs 16 come into contact with the end in the cell stacking direction of the cell stack 2, the reinforcing portions 25 connecting the upright walls 24 prevent the upright walls 24 from folding toward and away from each other.In addition, although the reinforcement portions 25 divide the relief portions 22 between each pair of upright walls 24, a plurality of cutout portions 23 communicate with each of the divided relief portions 22. Thus, it is possible to cause the cooling water to flow through the flow path in the recess 14 to flow in the respective relief portions.

[0026] The embodiment described above can be modified as follows.

[0027] In the above-described embodiment, in each of the lightening portions 22 divided by the reinforcing portions 25, the cutout portions 23 are formed at the center of the upright walls 24 in the direction in which the ribs 16 extend. However, the positions of the cutout portions 23 in the extending direction of the ribs 16 can be changed as needed. For each of the lightening portions 22 divided by the reinforcing portions 25, one cutout portion 23 may be formed at one end in the extending direction of the rib 16 of one of the upright walls 24 in each pair, and another cutout portion 23 may be formed at the other end in the extending direction of the rib 16 of the other upright wall 24.

[0028] Instead of forming one cutout portion 23 in each upright wall 24 of each pair, a plurality of cutout portions 23 may be formed in one of the upright walls 24 of each pair.

[0029] The reinforcement sections 25 do not necessarily have to be provided.

[0030] The tube assembly includes an end plate having an opposing surface facing one end in a cell stacking direction of a cell stack, a recess open in the opposing surface and forming a flow path, and ribs projecting from the bottom surface of the recess to the opening position of the recess. Portions of a resin sheet covering the opposing surface and the distal end surfaces in the projecting direction of the ribs contact the end in the cell stacking direction of the cell stack. The portions of the resin sheet covering the distal end surfaces in the projecting direction of the ribs each have a cooling channel that causes cooling water in the flow path to flow to the space between those portions of the resin sheet and a contact surface of the end in the cell stacking direction of the cell stack.

Claims

[1] A tube assembly (3) attached to one end in a cell stacking direction of a cell stack (2) in a fuel cell (1) and used to supply a coolant to the cell stack (2) and discharge a coolant from the cell stack (2), the tube assembly (3) comprising: an end plate (4) having an opposite surface (12) facing the end in the cell stacking direction of the cell stack (2); a recess (14) open in the opposite surface (12) and forming a flow path in which the coolant flows; a rib (16) projecting from a bottom surface (14a) of the recess (14) to an opening position of the recess (14) on the opposite surface (12); and a plastic layer (13) formed to cover the opposing surface (12), the recess (14) and the rib (16), wherein portions of the plastic layer (13) covering the opposing surface (12) and a distal end surface in a projecting direction of the rib (16) are in contact with the end in the cell stacking direction of the cell stack (2), whereby the pipe structure (3) characterized by is that the portion of the plastic layer (13) covering the distal end surface in the protruding direction of the rib (16) has a cooling channel (21) which causes the coolant to flow in the flow path formed by the recess (14) to a space between that portion of the plastic layer (13) and a contact surface of the end in the cell stacking direction of the cell stack (2), wherein the cooling channel (21) in the portion of the plastic layer (13) covering the distal end surface in a projecting direction of the rib (16) comprises: a relief portion (22) open to the end in the cell stacking direction of the cell stack (2), and a plurality of cutout sections (23) enabling the relief section (22) to communicate with the flow path. [2] Pipe structure (3) according to claim 1, characterized by , that the recess (14) is formed along the opposite surface (12) so that it extends in a flow direction of the coolant in the flow path in the recess (14), the rib (16) is designed to extend in the same direction as the direction in which the recess (14) extends, and the relief portion (22) is formed to extend along the rib (16). [3] Pipe structure (3) according to claim 2, characterized by , that the lightening portion (22) is provided between a pair of upright walls (24) extending parallel to the rib (16) in the portion of the plastic sheet (13) covering the distal end surface in the projecting direction of the rib (16), the upright walls (24) are connected to each other by a plurality of reinforcing portions (25) provided at intervals in an extending direction of the rib (16), the lightening section (22) is one of a plurality of lightening sections (22) divided by the reinforcing sections (25), and the cutout sections (23) in the upright walls (24) are formed such that two or more of the cutout sections (23) are in communication with each of the relief sections (22).

Images