JP6082309B2 - In-vehicle fuel cell system - Google Patents

Description

  The present invention includes a fuel cell stack in which a plurality of fuel cells that generate power by an electrochemical reaction between a fuel gas and an oxidant gas are stacked, and a casing that houses the fuel cell stack and is mounted on a vehicle. The present invention relates to a fuel cell system.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure in which an anode electrode is disposed on one side of an electrolyte membrane made of a polymer ion exchange membrane and a cathode electrode is disposed on the other side of the electrolyte membrane ( MEA) is provided with a power generation cell sandwiched between separators. This fuel cell is usually used as, for example, an in-vehicle fuel cell stack by stacking a predetermined number of power generation cells.

  In this fuel cell stack, there is a power generation cell in which a temperature drop is likely to be caused by heat radiation to the outside as compared with other power generation cells. For example, a power generation cell (hereinafter also referred to as an end cell) disposed at the end in the stacking direction has a large amount of heat released from a terminal plate, an end plate, etc. adjacent to the power generation cell, and the above-described temperature decrease becomes significant. ing.

  Therefore, for example, a fuel cell power generator disclosed in Patent Document 1 is known. The fuel cell power generator includes a stack portion in which a plurality of fuel cell single cells are stacked, a pair of current collector plates disposed at both ends of the stack portion, and an end member disposed on the outer periphery of the current collector plate. The fuel cell stack is surrounded by a casing in which a heat insulating material is fixed.

  And between the surface of the stack portion side of the heat insulating material and the surface of the stack portion, two or more contact prevention members made of an insulating material extending from the fuel cell stack are provided on the same surface, The heat insulating material is made longer in the same direction than the length between the contact prevention members arrange | positioned on the same surface.

JP 2008-130261 A

  In the fuel cell power generator described above, a heat insulating material is fixed inside the casing, and the entire fuel cell stack is surrounded by the casing. For this reason, there is a problem that the structure is complicated and the entire apparatus is enlarged.

  The present invention solves this type of problem, and provides an in-vehicle fuel cell system capable of easily simplifying and downsizing the configuration and keeping the fuel cell stack warm. Objective.

  The present invention includes a fuel cell stack in which a plurality of fuel cells that generate electricity by an electrochemical reaction between a fuel gas and an oxidant gas are stacked and a cooling medium is circulated, and the fuel cell stack is accommodated in a vehicle. The present invention relates to an in-vehicle fuel cell system including a casing that is arranged and a radiator that is disposed forward of the casing in the forward direction and that exchanges heat between the cooling medium and external air.

In this in-vehicle fuel cell system, the casing and the radiator are provided in a front box of the vehicle, and the fuel cell is stacked in the vehicle width direction of the vehicle. Between the outer periphery of the inner periphery and the fuel cell casing, with blowing space is formed, the casing includes an air inlet for introducing directly into the blast space external air passing through the radiator The air outlet is formed. The air intake port is a lower portion of the casing in front of the forward direction, and is provided at a position facing a side portion orthogonal to the stacking direction of the fuel cells and facing the radiator. The air discharge port is provided at a position on the rear side in the forward direction of the casing and facing the upper portion of the fuel cell.

  Further, in this in-vehicle fuel cell system, a plurality of air intakes are formed at the center side in the vehicle width direction at the lower part in the forward direction of the casing, while the upper part at the rear in the forward direction of the casing, It is preferable that one or more air discharge ports are formed at both ends in the vehicle width direction.

  Furthermore, in this in-vehicle fuel cell system, it is preferable that a partition portion for dividing the air blowing space portion is formed inside the casing in the forward direction.

  According to the present invention, the radiator is supplied with a cooling medium that is warmed by circulating through the fuel cell stack, and the external air is heated by exchanging heat with the cooling medium by the radiator. The heated external air is introduced from the air intake port into the air blowing space in the casing, so that the fuel cell stack can be kept warm. Therefore, it is not necessary to provide a heat insulating material in the casing, and the configuration can be easily simplified and downsized, and the fuel cell stack can be well kept warm.

1 is a schematic plan view of a fuel cell electric vehicle equipped with an in-vehicle fuel cell system according to an embodiment of the present invention. It is a schematic perspective view of the on-vehicle fuel cell system. FIG. 2 is a partially exploded perspective view of a fuel cell stack constituting the vehicle fuel cell system. 2 is an exploded perspective view of a fuel cell constituting the fuel cell stack. FIG. FIG. 3 is a partial cross-sectional plan view of the fuel cell stack. 2 is a cross-sectional side view of the fuel cell stack. FIG.

  As shown in FIG. 1, an in-vehicle fuel cell system 10 according to an embodiment of the present invention is accommodated in a front box (so-called motor room) 12 f of a fuel cell electric vehicle (fuel cell vehicle) 12. The in-vehicle fuel cell system 10 includes a fuel cell stack 14, a casing 16 that accommodates the fuel cell stack 14, and a forward direction (arrow Af direction) ahead of the casing 16, and a cooling medium, which will be described later, is external air. And a radiator 17 for exchanging heat with each other (see FIGS. 1 and 2).

  As shown in FIG. 3, the fuel cell stack 14 has a vehicle width in which a plurality of horizontally long fuel cells 18 intersect the vehicle length direction (vehicle traveling direction) (arrow A direction) of the fuel cell electric vehicle 12 in a standing posture. They are stacked in the direction (arrow B direction).

  At one end in the stacking direction of the fuel cell 18, a first terminal plate 20a, a first insulating plate 22a, and a first end plate 24a are sequentially arranged outward. At the other end of the fuel cell 18 in the stacking direction, a second terminal plate 20b, a second insulating plate 22b, and a second end plate 24b are sequentially disposed outward. The first end plate 24a and the second end plate 24b are set to have outer dimensions larger than the outer dimensions of the fuel cell 18, the first insulating plate 22a, and the second insulating plate 22b.

  As shown in FIG. 4, the fuel cell 18 includes an electrolyte membrane / electrode structure 26, and a first metal separator 28 and a second metal separator 30 that sandwich the electrolyte membrane / electrode structure 26. The first metal separator 28 and the second metal separator 30 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate that has been subjected to anticorrosion surface treatment on its metal surface. The first metal separator 28 and the second metal separator 30 have a rectangular planar shape, and are formed into a concavo-convex shape by pressing a metal thin plate into a wave shape. Instead of the first metal separator 28 and the second metal separator 30, for example, a carbon separator may be used.

  The electrolyte membrane / electrode structure 26 includes, for example, a solid polymer electrolyte membrane 32 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode electrode 34 and a cathode electrode 36 sandwiching the solid polymer electrolyte membrane 32. Prepare. The solid polymer electrolyte membrane 32 has a larger single-sided size than the anode electrode 34 and the cathode electrode 36.

  The anode electrode 34 and the cathode electrode 36 are set to the same single-sided dimension (see FIG. 4). The electrolyte membrane / electrode structure 26 may constitute a so-called step MEA in which the anode electrode 34 and the cathode electrode 36 are set to have different plane dimensions.

  The anode electrode 34 and the cathode electrode 36 are obtained by uniformly applying a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof to the surface of the gas diffusion layer. And an electrode catalyst layer (not shown) to be formed. The electrode catalyst layer is formed on both surfaces of the solid polymer electrolyte membrane 32, for example.

  One end edge of the fuel cell 18 in the arrow A direction (horizontal direction intersecting the arrow B direction in FIG. 4) communicates with each other in the arrow B direction, which is the stacking direction, and an oxidant gas, for example, an oxygen-containing gas An oxidant gas supply communication hole 38a for supplying gas, a cooling medium supply communication hole 40a for supplying a cooling medium, and a fuel gas discharge communication hole 42b for discharging a fuel gas, for example, a hydrogen-containing gas, are indicated by arrows. Arranged in the C direction (vertical direction).

  The other end edge of the fuel cell 18 in the direction of arrow A communicates with each other in the direction of arrow B, and supplies a fuel gas supply communication hole 42a for supplying fuel gas, and a cooling medium discharge communication hole for discharging the cooling medium. 40b and an oxidant gas discharge communication hole 38b for discharging the oxidant gas are arranged in the arrow C direction.

  On the surface 28a of the first metal separator 28 facing the electrolyte membrane / electrode structure 26, for example, a fuel gas passage 44 extending in the direction of arrow A is formed. The fuel gas flow path 44 communicates with the fuel gas supply communication hole 42a and the fuel gas discharge communication hole 42b.

  On the surface 30a of the second metal separator 30 facing the electrolyte membrane / electrode structure 26, for example, an oxidant gas channel 46 extending in the arrow A direction is provided. The oxidant gas flow path 46 communicates with the oxidant gas supply communication hole 38a and the oxidant gas discharge communication hole 38b. The oxidant gas channel 46 and the fuel gas channel 44 are configured to face each other (the flow direction of the oxidant gas is opposite to the flow direction of the fuel gas).

  A cooling medium flow path 48 communicating with the cooling medium supply communication hole 40a and the cooling medium discharge communication hole 40b is formed between the surface 28b of the first metal separator 28 and the surface 30b of the second metal separator 30 adjacent to each other. Is done. The cooling medium channel 48 is formed by overlapping the back surface shape of the fuel gas channel 44 and the back surface shape of the oxidant gas channel 46.

  The first seal member 50 is integrated with the surfaces 28 a and 28 b of the first metal separator 28 around the outer peripheral end of the first metal separator 28. The second seal member 52 is integrated with the surfaces 30 a and 30 b of the second metal separator 30 around the outer peripheral end of the second metal separator 30.

  For the first seal member 50 and the second seal member 52, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or the like, cushion material Alternatively, an elastic seal member such as a packing material is used.

  As shown in FIG. 3, terminal portions 58a and 58b extending outward in the stacking direction are provided at substantially the center of the first terminal plate 20a and the second terminal plate 20b. The terminal portion 58a is inserted into the insulating cylinder 60, passes through the hole portion 62a of the first insulating plate 22a and the hole portion 64a of the first end plate 24a, and protrudes outside the first end plate 24a. The terminal portion 58b is inserted into the insulating cylinder 60, passes through the hole portion 62b of the second insulating plate 22b and the hole portion 64b of the second end plate 24b, and protrudes outside the second end plate 24b.

  The first insulating plate 22a and the second insulating plate 22b are formed of an insulating material such as polycarbonate (PC) or phenol resin. The first insulating plate 22a is provided with a rectangular recess 66a at the center, and a hole 62a communicates with the approximate center of the recess 66a. The first terminal plate 20a is accommodated in the recess 66a, and the terminal portion 58a of the first terminal plate 20a is inserted into the hole portion 62a with the insulating cylinder 60 interposed therebetween.

  The second insulating plate 22b is provided with a rectangular recess 66b at the center, and the hole 62b communicates with the approximate center of the recess 66b. The second terminal plate 20b is accommodated in the recess 66b, and the terminal portion 58b of the second terminal plate 20b is inserted into the hole portion 62b with the insulating cylinder 60 interposed therebetween.

  The first insulating plate 22a and the first end plate 24a are formed with an oxidant gas supply communication hole 38a, an oxidant gas discharge communication hole 38b, a fuel gas supply communication hole 42a, and a fuel gas discharge communication hole 42b. A cooling medium supply communication hole 40a and a cooling medium discharge communication hole 40b are formed in the second insulating plate 22b and the second end plate 24b. Arbitrary communication holes can be distributed and provided on the first end plate 24a side and the second end plate 24b side, respectively.

  As shown in FIG. 1, one end of a cooling medium introduction pipe 67a is connected to the cooling medium supply communication hole 40a of the second end plate 24b, and the cooling medium discharge communication hole 40b of the second end plate 24b is connected to the cooling medium supply communication hole 40b. One end of the cooling medium outlet pipe 67b is connected. The other end of the cooling medium introduction pipe 67a and the other end of the cooling medium outlet pipe 67b are connected to the inlet and the outlet of the radiator 17, and the cooling medium introduction pipe 67a or the cooling medium outlet pipe 67b is shown in the figure. A circulating pump is provided.

  The oxidant gas supply communication hole 38a and the oxidant gas discharge communication hole 38b of the first end plate 24a are connected to an oxidant gas supply device (not shown). The fuel gas supply communication hole 42a and the fuel gas discharge communication hole 42b of the first end plate 24a are connected to a fuel gas supply device (not shown).

  As shown in FIGS. 1 and 2, the casing 16 is configured by a first end plate 24 a and a second end plate 24 b at two sides at both ends in the vehicle width direction (arrow B direction). Two sides of both ends of the casing 16 in the vehicle length direction (arrow A direction) are constituted by a front side plate (forward plate in the forward direction) 68 and a rear side plate (plate in the forward direction). Two sides of both ends of the casing 16 in the vehicle height direction (arrow C direction) are constituted by an upper plate 72 and a down plate 74.

  The front side plate 68, the rear side plate 70, the upper plate 72, and the down plate 74 have a plate shape, and are formed by, for example, extrusion molding, casting, machining, or the like. The front side plate 68, the rear side plate 70, the upper plate 72, and the down plate 74 are fixed to the first end plate 24a and the second end plate 24b (to each other) by screws 76 as necessary. The front side plate 68, the rear side plate 70, the upper plate 72, and the down plate 74 bear the tightening load of the fuel cell stack 14.

  As shown in FIGS. 2, 5, and 6, an air blowing space 78 is formed between the inner periphery of the casing 16 and the outer periphery of the fuel cell stack 14. In the fuel cell stack 14, the first end plate 24 a and the second end plate 24 b are set to have outer dimensions larger than the outer dimensions of the fuel cell 18, and the outer periphery of the stacked fuel cells 18 and the inner periphery of the casing 16. A space 78 for air blowing is formed between the two.

  The front side plate 68 that is forward of the casing 16 in the forward direction is provided with a partition 80 extending in the vertical direction at the center in the long side direction (arrow B direction) of the inner surface (the surface on the fuel cell stack 14 side). It is done. The partition portion 80 extends over the entire width direction (arrow C direction) of the front side plate 68 and bulges to the fuel cell 18 side, and divides the air blowing space portion 78. The partition portion 80 may be formed integrally with the front side plate 68, or a separate body may be joined to the front side plate 68.

  A plurality of, for example, two (not limited to two) air intakes 82a and 82b are formed at the lower portion of the front side plate 68 with the partition portion 80 sandwiched between the center in the vehicle width direction. The air intake ports 82a and 82b have a rectangular shape, but can be set in various shapes such as a circular shape.

  The upper plate 72 that is the upper part of the casing 16 is formed with one (or two or more) air discharge ports 84a and 84b that are located rearward in the vehicle length direction and outward in the longitudinal direction (vehicle width direction). The The air discharge ports 84 a and 84 b have a rectangular shape (or a circular shape or the like) and are arranged on the upper rear side of the casing 16. The blower space 78 communicates with the two air intake ports 82a and 82b on the inlet side, and communicates with the two air discharge ports 84a and 84b on the outlet side.

  The operation of the in-vehicle fuel cell system 10 configured as described above will be described below.

  First, as shown in FIGS. 2 and 3, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas supply communication hole 38a of the first end plate 24a. A fuel gas such as a hydrogen-containing gas is supplied to the fuel gas supply communication hole 42a of the first end plate 24a. Furthermore, in the second end plate 24b, a coolant such as pure water, ethylene glycol, or oil is supplied to the coolant supply passage 40a.

  Therefore, as shown in FIG. 4, the oxidant gas is introduced into the oxidant gas flow path 46 of the second metal separator 30 from the oxidant gas supply communication hole 38a. The oxidant gas moves in the direction of arrow A along the oxidant gas flow path 46 and is supplied to the cathode electrode 36 of the electrolyte membrane / electrode structure 26.

  On the other hand, the fuel gas is supplied to the fuel gas passage 44 of the first metal separator 28 from the fuel gas supply communication hole 42a. The fuel gas moves in the direction of arrow A along the fuel gas flow path 44 and is supplied to the anode electrode 34 of the electrolyte membrane / electrode structure 26.

  Therefore, in the electrolyte membrane / electrode structure 26, the oxidizing gas supplied to the cathode electrode 36 and the fuel gas supplied to the anode electrode 34 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is called.

  Next, the oxidant gas consumed by being supplied to the cathode electrode 36 of the electrolyte membrane / electrode structure 26 is discharged in the direction of arrow B along the oxidant gas discharge communication hole 38b. On the other hand, the fuel gas supplied to and consumed by the anode electrode 34 of the electrolyte membrane / electrode structure 26 is discharged in the direction of arrow B along the fuel gas discharge communication hole 42b.

  The cooling medium supplied to the pair of cooling medium supply communication holes 40 a is introduced into the cooling medium flow path 48 between the first metal separator 28 and the second metal separator 30. The cooling medium moves in the direction of arrow A to cool the electrolyte membrane / electrode structure 26 and then is discharged in the direction of arrow B along the cooling medium discharge communication hole 40b.

  As shown in FIG. 1, the cooling medium warmed by cooling each electrolyte membrane / electrode structure 26 is led out to the cooling medium outlet pipe 67 b and supplied to the radiator 17. The fuel cell electric vehicle 12 travels in the direction of the arrow Af, and the radiator 17 cools the cooling medium by external air. In other words, the cooling medium heats (exchanges heat) external air as a heating fluid.

  In this case, in this embodiment, as shown in FIGS. 2, 5, and 6, the external air heated by the heat exchange with the cooling medium is blown into the casing 16 from the pair of air intakes 82 a and 82 b. Introduced into the space 78. After the external air introduced into the air blowing space 78 is evenly distributed from the substantially central portion of the fuel cell stack 14 to the left and right (both sides in the direction of arrow B) by the partition 80, both ends of the fuel cell stack 14 in the stacking direction. The air is discharged outward from the pair of air discharge ports 84a and 84b.

  External air flows from the inside of the front side plate 68 to the outside of the upper plate 72. At that time, as shown in FIG. 6, the external air flows through the entire outer periphery of the fuel cell stack 14 by flowing above and below the fuel cell stack 14.

  For this reason, in the fuel cell stack 14, it is possible to heat the fuel cells 18 at both ends in the stacking direction, which are particularly likely to cause a temperature drop, and to maintain the desired temperature state over the entire stacking direction. Become. Therefore, there is no need to dispose a heat insulating material in the casing 16, and it is possible to easily simplify the configuration and reduce the size, and to effectively keep the fuel cell stack 14 warm.

DESCRIPTION OF SYMBOLS 10 ... Vehicle-mounted fuel cell system 12 ... Fuel cell electric vehicle 12f ... Front box 14 ... Fuel cell stack 16 ... Casing 17 ... Radiator 18 ... Fuel cell 24a, 24b ... End plate 26 ... Electrolyte membrane and electrode structure 28, 30 ... Metal separator 32 ... Solid polymer electrolyte membrane 34 ... Anode electrode 36 ... Cathode electrode 38a ... Oxidant gas supply communication hole 38b ... Oxidant gas discharge communication hole 40a ... Cooling medium supply communication hole 40b ... Cooling medium discharge communication hole 42a ... Fuel Gas supply communication hole 42b ... Fuel gas discharge communication hole 44 ... Fuel gas flow path 46 ... Oxidant gas flow path 48 ... Cooling medium flow path 67a ... Cooling medium introduction pipe 67b ... Cooling medium outlet pipe 68 ... Front side plate 70 ... Rear Side plate 72 ... Upper plate 74 ... Down plate 78 ... Blower space 80 ... partition portion 82a, 82b ... air intake 84a, 84b ... air outlet

Claims (3)

A fuel cell stack in which a plurality of fuel cells that generate electricity by an electrochemical reaction between a fuel gas and an oxidant gas are stacked, and a cooling medium is circulated;
A casing that houses the fuel cell stack and is mounted on a vehicle;
A radiator that is disposed forward of the casing in a forward direction and that exchanges heat between the cooling medium and external air;
An in-vehicle fuel cell system comprising:
The casing and the radiator are provided in a front box of the vehicle,
The fuel cell is stacked in the vehicle width direction of the vehicle,
Between the inner periphery of the casing and the outer periphery of the fuel cell, a space for air blowing is formed,
The casing is formed with an air intake for directly introducing the external air that has passed through the radiator into the air blowing space, and an air outlet .
The air intake port is a lower portion in the forward direction of the casing and is provided at a position facing a side portion orthogonal to the stacking direction of the fuel cells and facing the radiator,
The air outlet is a forward direction behind the upper portion of the casing, vehicle fuel cell system characterized that you have provided at a position opposed to the upper portion of the fuel cell. In the on-vehicle fuel cell system according to claim 1 , a plurality of the air intakes are formed at a center side in the vehicle width direction at a lower portion in the forward direction of the casing.
An in-vehicle fuel cell system, wherein at least one air discharge port is formed at each of both ends in the vehicle width direction at an upper part of the casing in the forward direction. The in-vehicle fuel cell system according to claim 2 , wherein a partition portion that divides the air blowing space portion is formed inside the casing in the forward direction in the forward direction.

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