JP2014150003A - Fuel cell stack - Google Patents

Abstract

Heat dissipation to the outside can be satisfactorily suppressed through a terminal joint, and in particular, it is possible to prevent as much as possible a decrease in power generation performance of a fuel cell disposed at an end in a stacking direction.
A fuel cell stack 10 includes a plurality of fuel cells 12 stacked, and a terminal plate 14a, an insulating plate 16a, and an end plate 18a are disposed at one end of the fuel cells 12 in the stacking direction. The terminal plate 14a includes a terminal joint 50a that protrudes outside through the insulating plate 16a and the end plate 18a, and a heater wire 62a is wound around the outer periphery of the terminal joint 50a.
[Selection] Figure 2

Description

  The present invention provides a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked, and includes a stacked body in which a plurality of the fuel cells are stacked. The present invention relates to a fuel cell stack in which a terminal plate, an insulating plate, and an end plate are stacked at both ends of the body in the stacking direction.

  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 surface side ( MEA) is provided with a power generation unit sandwiched between a pair of separators. This type of fuel cell is usually used as, for example, an in-vehicle fuel cell stack by stacking a predetermined number (for example, several hundreds) of power generation units.

  When a fuel cell stack is mounted on an automobile, a space in the height direction is often restricted. For this reason, the structure which restrains the dimension of the height direction of a fuel cell stack low is desired, for example, the fuel cell stack disclosed by patent document 1 is known.

  In this fuel cell stack, unit fuel cells provided with an anode electrode and a cathode electrode on both sides of an electrolyte, the unit fuel cells are stacked in a horizontal direction via a separator, and a reactive gas for each electrode, A communication hole for supplying and discharging the coolant is formed so as to penetrate through the surfaces of the electrodes and the like. A conductive flat plate is provided on the end surface of the unit fuel cell located on the outermost side in the stacking direction, and a protrusion made of a conductive material having an outer periphery insulated from the flat plate in a substantially vertical direction is provided. At the same time, this protrusion is configured as a terminal for extracting power.

  With this configuration, the internal manifold structure suppresses the expansion of the occupied space to the surroundings as much as possible, eliminates the protrusion of the flat plate around the projections, and takes out the electric power while ensuring insulation from the outside. Is possible.

JP 2002-1000039 A

  By the way, in the fuel cell stack described above, a protruding portion (terminal joint) is provided so as to protrude outward from the conductive flat plate (terminal plate) disposed at the end portion in the stacking direction. This protrusion actually penetrates the end plate and is exposed outward in the stacking direction of the fuel cell stack.

  For this reason, the heat in the fuel cell stack is easily radiated to the outside through the end plate from the protruding portion of the terminal plate, and the heat radiation amount increases. As a result, the temperature at the stack end decreases, and the power generation performance of the unit fuel cells at the stacking direction end may decrease.

  The present invention solves this type of problem, and can effectively suppress heat dissipation to the outside through the terminal joint, and particularly reduces the power generation performance of the fuel cell disposed at the end in the stacking direction. An object of the present invention is to provide a fuel cell stack that can be prevented as much as possible.

  The present invention provides a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked, and includes a stacked body in which a plurality of the fuel cells are stacked. The present invention relates to a fuel cell stack in which a terminal plate, an insulating plate, and an end plate are stacked at both ends in the stacking direction of the body.

  In this fuel cell stack, the terminal plate has a terminal joint that protrudes outside through an insulating plate and an end plate arranged outward in the stacking direction, and is connected to the outer periphery of the terminal joint or the terminal joint. A heater wire is wound around the outer periphery of the bus bar.

  Moreover, in this fuel cell stack, it is preferable that the heater wire constitutes a ring-shaped heater wound in a cylindrical shape in advance, and the ring-shaped heater is inserted into the outer periphery of the terminal joint.

  Further, in this fuel cell stack, a large diameter portion and a small diameter portion are provided coaxially on the outer periphery of the terminal joint, and a heater wire is wound around the small diameter portion, and the small diameter portion and the large diameter portion The step is preferably set to a size larger than the diameter of the heater wire.

  According to the present invention, the heater wire is wound around the outer periphery of the terminal joint protruding outward from the terminal plate in the stacking direction or the outer periphery of the bus bar connected to the terminal joint. Therefore, the terminal joint is heated by the heater wire directly or via the bus bar.

  Thereby, it is possible to satisfactorily suppress heat dissipation to the outside through the terminal joint, and in particular, the fuel cell disposed at the end portion in the stacking direction prevents a decrease in power generation performance due to a temperature decrease as much as possible. It becomes possible.

1 is a perspective explanatory view of a fuel cell stack according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the fuel cell stack taken along line II-II in FIG. 1. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. It is sectional drawing of the fuel cell stack which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the fuel cell stack which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the fuel cell stack which concerns on the 4th Embodiment of this invention. It is sectional drawing of the fuel cell stack which concerns on the 5th Embodiment of this invention. It is sectional drawing of the fuel cell stack which concerns on the 6th Embodiment of this invention.

  As shown in FIGS. 1 and 2, the fuel cell stack 10 according to the first embodiment of the present invention has a plurality of fuel cells 12 stacked in the direction of arrow A (horizontal direction) or the direction of arrow C (vertical direction). The laminated body 13 is provided.

  A terminal plate 14a, an insulating plate 16a, and an end plate 18a are disposed at one end of the stacked body 13 in the stacking direction. A terminal plate 14b, an insulating plate 16b, and an end plate 18b are disposed at the other end of the stacked body 13 in the stacking direction.

  As shown in FIGS. 2 and 3, in the fuel cell 12, an electrolyte membrane / electrode structure (MEA) 20 is sandwiched between a first separator 22 and a second separator 24. The first separator 22 and the second separator 24 are constituted by, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a vertically long metal plate obtained by applying a surface treatment for corrosion prevention to the metal surface.

  The first separator 22 and the second separator 24 have a rectangular planar shape, and are formed into a concavo-convex shape by pressing a metal thin plate into a wave shape. In addition, you may comprise the 1st separator 22 and the 2nd separator 24 with a carbon separator, for example. The first separator 22 and the second separator 24 have a vertically long shape, but may have a horizontally long shape.

  At the upper edge of the fuel cell 12 in the direction of arrow C (vertical direction in FIG. 3), an oxidant for supplying an oxidant gas, for example, an oxygen-containing gas, communicates with each other in the direction of arrow A, which is the stacking direction. An agent gas inlet communication hole 26a, a cooling medium inlet communication hole 28a for supplying a cooling medium, and a fuel gas inlet communication hole 30a for supplying a fuel gas, for example, a hydrogen-containing gas, are arranged in the arrow B direction. Provided.

  The lower end edge of the fuel cell 12 in the direction of arrow C communicates with each other in the direction of arrow A, a fuel gas outlet communication hole 30b for discharging fuel gas, and a cooling medium outlet communication hole 28b for discharging cooling medium. , And oxidant gas outlet communication holes 26b for discharging the oxidant gas are arranged in the arrow B direction.

  An oxidant gas flow path 32 communicating with the oxidant gas inlet communication hole 26a and the oxidant gas outlet communication hole 26b is formed on the surface 22a of the first separator 22 facing the electrolyte membrane / electrode structure 20 along the vertical direction. Provided.

  A fuel gas channel 34 communicating with the fuel gas inlet communication hole 30a and the fuel gas outlet communication hole 30b is provided along the vertical direction on the surface 24a of the second separator 24 facing the electrolyte membrane / electrode structure 20. .

  A cooling medium that connects the cooling medium inlet communication hole 28a and the cooling medium outlet communication hole 28b between the surface 22b of the first separator 22 and the surface 24b of the second separator 24 that constitute the fuel cells 12 adjacent to each other. A flow path 36 is provided along the vertical direction.

  The first seal member 38 is integrally or individually provided on the surfaces 22 a and 22 b of the first separator 22, and the second seal member 40 is integrally formed on the surfaces 24 a and 24 b of the second separator 24. Or it is provided separately. As the first seal member 38 and the second seal member 40, for example, EPDM, NBR, fluororubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, or acrylic rubber or the like, cushion A seal member having elasticity such as a material or a packing material is used.

  The electrolyte membrane / electrode structure 20 includes, for example, a solid polymer electrolyte membrane 42 in which a perfluorosulfonic acid thin film (or hydrocarbon-based membrane) is impregnated with water, and a cathode electrode sandwiching the solid polymer electrolyte membrane 42 44 and an anode electrode 46.

  The cathode electrode 44 and the anode electrode 46 are an electrode catalyst formed by uniformly applying a gas diffusion layer made of carbon paper or the like and porous carbon particles having a platinum alloy supported on the surface to the surface of the gas diffusion layer. And having a layer. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 42.

  As shown in FIG. 2, the insulating plates 16a and 16b have recesses 48a and 48b formed on the surface facing the laminated body 13, and the terminal plates 14a and 14b are accommodated in the recesses 48a and 48b. The terminal plates 14a and 14b are made of a conductive material such as copper, stainless steel, or aluminum.

  A surface of the terminal plate 14a facing the insulating plate 16a is provided with a terminal joint (power extraction terminal) 50a that protrudes outward in the stacking direction (arrow A direction) and is exposed from the end plate 18a. The terminal joint 50a is made of a conductive material such as copper, stainless steel, and aluminum, has a cylindrical shape, and is fixed to the terminal plate 14a by friction stir welding (FSW), friction welding (FW), or the like. The terminal joint 50a may be integrally formed on the terminal plate 14a by casting. A screw hole 52a is formed in the axial direction at the tip of the terminal joint 50a.

  The insulating plate 16a is provided with an insulating cylindrical portion 54a that circulates around the terminal joint 50a and protrudes outward in the stacking direction. The cylindrical portion 54a is inserted (freely fitted) into a hole 56a formed in the end plate 18a. One end of a bus bar (conductive plate) 60a is fixed to the terminal joint 50a via a screw 58a, and the other end of the bus bar 60a protrudes to the side of the end plate 18a and is connected to a cable (not shown). .

  In the first embodiment, the heater wire 62a is tightly wound around the outer periphery of the terminal joint 50a. The heater wire 62a constitutes a ring-shaped heater wound in a cylindrical shape in advance, and the ring-shaped heater is inserted into the outer periphery of the terminal joint 50a. Both ends of the heater wire 62a are connected to the heater power supply 64a. A predetermined gap is formed between the outer periphery of the heater wire 62a and the inner periphery of the cylindrical portion 54a. For example, an insulating process such as an insulating varnish is performed on the outer periphery of the terminal joint 50a.

  A cover member 66a is provided to surround the bus bar 60a and the terminal joint 50a. The cover member 66a has a cylindrical body portion 70a that is slidably fitted to an outer wall surface of the cylindrical portion 54a of the insulating plate 16a via a radial seal, for example, an O-ring 68a. The cover member 66a has an arm portion 72a that accommodates the bus bar 60a, and a cap portion 74a is attached to the proximal end of the arm portion 72a. The heater wire 62a is inserted through the cap portion 74a.

  The terminal joint 50a can be set in various shapes such as a prismatic shape and an L shape. The terminal plate 14b and its peripheral structure are configured in the same manner as the terminal plate 14a and its peripheral structure, and the same constituent elements are denoted by the same reference numeral with “b” instead of “a”. Detailed description thereof will be omitted. Further, a common heater power source may be used as the heater power sources 64a and 64b.

  As shown in FIG. 1, a plurality of connecting members 76 are bridged between the end plate 18a and the end plate 18b. The connecting members 76 have a long plate shape, and two connecting members 76 are disposed on the long side of the fuel cell stack 10 and one on the short side of the fuel cell stack 10. Both ends of the connecting member 76 in the direction of arrow A are fixed to the side portions of the end plate 18a and the end plate 18b via bolts 78, and a predetermined tightening load is applied between the end plates 18a and 18b in the stacking direction. Is done.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 26a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 30a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 28a.

  For this reason, as shown in FIG. 3, the oxidant gas is introduced into the oxidant gas flow path 32 of the first separator 22 from the oxidant gas inlet communication hole 26a. The oxidant gas is supplied to the cathode electrode 44 constituting the electrolyte membrane / electrode structure 20 while moving downward in the direction of arrow C.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 34 of the second separator 24 from the fuel gas inlet communication hole 30a. The fuel gas is supplied to the anode electrode 46 constituting the electrolyte membrane / electrode structure 20 while moving downward in the direction of arrow C.

  Therefore, in the electrolyte membrane / electrode structure 20, the oxidant gas supplied to the cathode electrode 44 and the fuel gas supplied to the anode electrode 46 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is called. The fuel cells 12 are electrically connected in series, and electric power is taken out from the terminal joints 50a and 50b provided on the terminal plates 14a and 14b disposed at both ends of the fuel cells 12 in the stacking direction. For example, a travel motor (not shown) is driven.

  Next, the oxidant gas consumed by being supplied to the cathode electrode 44 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 26b. On the other hand, the fuel gas consumed by being supplied to the anode electrode 46 is discharged in the direction of arrow A along the fuel gas outlet communication hole 30b.

  The cooling medium supplied to the cooling medium inlet communication hole 28a is introduced into the cooling medium flow path 36 between the first and second separators 22 and 24, and flows downward in the direction of arrow C. The cooling medium cools the electrolyte membrane / electrode structure 20 and then is discharged to the cooling medium outlet communication hole 28b.

  In this case, in the first embodiment, as shown in FIG. 2, the heater wire 62a is wound around the outer periphery of the terminal joint 50a that protrudes outward from the terminal plate 14a in the stacking direction. For this reason, the terminal joint 50a is directly heated under the action of the heater power supply 64a connected to the heater wire 62a. On the other hand, a heater wire 62b is wound around the outer periphery of the terminal joint 50b protruding outward from the terminal plate 14b in the stacking direction. Therefore, the terminal joint 50b is directly heated under the action of the heater power supply 64b connected to the heater wire 62b.

  Thereby, it can suppress favorably that it is thermally radiated outside via terminal joints 50a and 50b. For this reason, especially the fuel cell 12 arrange | positioned at the stacking direction edge part has the effect that it becomes possible to prevent the fall of the power generation performance by a temperature fall as much as possible. In addition, you may provide the heater wire connected to the heater power supply only in one of the terminal joints 50a and 50b. The same applies to the second and subsequent embodiments described below.

  FIG. 4 is a cross-sectional view of a fuel cell stack 80 according to the second embodiment of the present invention. The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the third and subsequent embodiments described below, detailed description thereof is omitted.

  The fuel cell stack 80 includes terminal plates 82a and 82b. A terminal joint 84a is provided on the terminal plate 82a so as to protrude outward in the stacking direction (arrow A direction). The terminal joint 84a has a cylindrical shape, and a large diameter portion 86a and a small diameter portion 88a are provided coaxially on the outer periphery thereof. The small diameter portion 88a is provided over a predetermined length in the axial direction, and a heater wire 62a is wound around the small diameter portion 88a. The step Sa between the small diameter portion 88a and the large diameter portion 86a is set to a size larger than the diameter of the heater wire 62a.

  The terminal plate 82b is provided with a terminal joint 84b that protrudes outward in the stacking direction (arrow A direction). A large diameter portion 86b and a small diameter portion 88b are provided coaxially on the outer periphery of the terminal joint 84b. The small diameter portion 88b is provided over a predetermined length in the axial direction, and a heater wire 62b is wound around the small diameter portion 88b. The step Sb between the small diameter portion 88b and the large diameter portion 86b is set to a size larger than the diameter of the heater wire 62b.

  In the second embodiment configured as described above, the heater wires 62a and 62b are provided on the outer circumferences of the terminal joints 84a and 84b, and it is preferable that heat is radiated to the outside through the terminal joints 84a and 84b. The same effects as those of the first embodiment can be obtained, such as being able to be suppressed.

  Moreover, in the second embodiment, small diameter portions 88a and 88b are formed on the outer periphery of the terminal joints 84a and 84b, and the heater wires 62a and 62b are wound around the outer periphery of the small diameter portions 88a and 88b. The step Sa between the small diameter portion 88a and the large diameter portion 86a is set to be larger than the diameter of the heater wire 62a, while the step Sb between the small diameter portion 88b and the large diameter portion 86b is the diameter of the heater wire 62b. Is set to a larger dimension.

  For this reason, for example, when the terminal joints 84a and 84b expand and contract in the stacking direction (axial direction), the sliding contact between the heater wire 62a and the inner surface of the tubular portion 54a and the contact between the heater wire 62b and the inner surface of the tubular portion 54b. The sliding contact can be surely prevented.

  FIG. 5 is a cross-sectional view of a fuel cell stack 90 according to the third embodiment of the present invention.

  In the fuel cell stack 90, bus bars 60a and 60b are screwed to the terminal joints 50a and 50b, and heater wires 92a and 92b are wound around the outer periphery of the bus bars 60a and 60b. In addition, you may provide a large diameter part and a small diameter part in the outer periphery of bus-bar 60a, 60b similarly to 2nd Embodiment. The heater wires 92a and 92b are exposed to the outside through the arm portions 72a and 72b, and are connected to the heater power sources 64a and 64b. The terminal joints 50a and 50b may also be provided with heater wires 92a and 92b.

  In the third embodiment configured as described above, the heater wires 92a and 92b are wound around the bus bars 60a and 60b, and heat is transmitted from the bus bars 60a and 60b to the terminal joints 50a and 50b. . Therefore, it is possible to satisfactorily suppress heat dissipation to the outside through the terminal joints 50a and 50b. As a result, the same effects as those of the first and second embodiments can be obtained, for example, it is possible to prevent the power generation performance of the end fuel cell 12 from being lowered as much as possible.

  FIG. 6 is a cross-sectional view of a fuel cell stack 100 according to the fourth embodiment of the present invention.

  In the fuel cell stack 100, thin film heaters 102a and 102b are attached to the outer periphery of the terminal joints 50a and 50b. The thin film heaters 102a and 102b constitute a cylindrical film and are electrically connected to the heater power sources 64a and 64b through the conductive wires 104a and 104b.

  In the fourth embodiment configured as described above, since the thin film heaters 102a and 102b are used, the cross-sectional area becomes small, and the radial dimensions of the terminal joints 50a and 50b can be set to be small. In addition, the same effects as those of the first to third embodiments can be obtained, for example, it is possible to prevent the power generation performance of the end fuel cell 12 from being lowered as much as possible.

  FIG. 7 is a cross-sectional view of a fuel cell stack 110 according to the fifth embodiment of the present invention.

  In the fuel cell stack 110, the heater wires 112a and 112b are wound around the outer periphery of the terminal joints 50a and 50b in a right-handed and left-handed double winding. Both ends of the winding portion of the heater wire 112a and both ends of the winding portion of the heater wire 112b are disposed on the same side and are electrically connected to the heater power sources 64a and 64b.

  In the fifth embodiment configured as described above, it is possible to prevent a decrease in power generation performance of the fuel cell 12 at the end as much as possible, and the same as in the first to fourth embodiments. The effect is obtained.

  FIG. 8 is a cross-sectional view of a fuel cell stack 120 according to the sixth embodiment of the present invention.

  The fuel cell stack 120 includes terminal joints 122a and 122b. The terminal joints 122a and 122b have a columnar shape, and grooves 124a and 124b that spirally circulate are formed on the outer circumferences. Heater wires 126a and 126b are wound around the outer periphery of the terminal joints 122a and 122b along the groove portions 124a and 124b. The heater wires 126a and 126b are electrically connected to the heater power supplies 64a and 64b.

  In the sixth embodiment configured as described above, the heater wires 126a and 126b are disposed in the grooves 124a and 124b formed on the outer circumferences of the terminal joints 122a and 122b. For this reason, the terminal joints 122a and 122b have the advantage that the contact area with the heater wires 126a and 126b is increased, and the heat transfer efficiency is improved satisfactorily. Furthermore, the same effects as those of the first to fifth embodiments described above can be obtained, for example, it is possible to prevent the power generation performance of the end fuel cell 12 from being lowered as much as possible.

DESCRIPTION OF SYMBOLS 10, 80, 90, 100, 110, 120 ... Fuel cell stack 12 ... Fuel cell 13 ... Laminated body 14a, 14b, 82a, 82b ... Terminal plate 16a, 16b ... Insulating plate 18a, 18b ... End plate 20 ... Electrolyte membrane * Electrode structure 22, 24 ... Separator 26a ... Oxidant gas inlet communication hole 26b ... Oxidant gas outlet communication hole 28a ... Cooling medium inlet communication hole 28b ... Cooling medium outlet communication hole 30a ... Fuel gas inlet communication hole 30b ... Fuel gas outlet Communication hole 32 ... Oxidant gas channel 34 ... Fuel gas channel 36 ... Cooling medium channel 42 ... Solid polymer electrolyte membrane 44 ... Cathode electrode 46 ... Anode electrode 50a, 50b, 84a, 84b, 122a, 122b ... Terminal joint 54a, 54b ... cylindrical portions 60a, 60b ... bus bars 62a, 62b, 92a, 9 2b, 112a, 112b, 126a, 126b ... heater wires 64a, 64b ... heater power supply 66a ... cover members 102a, 102b ... thin film heaters 104a, 104b ... conductive wires 124a, 124b ... grooves

Claims (3)

Provided is a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked, and includes a stack in which a plurality of the fuel cells are stacked, and the stacking direction of the stack A fuel cell stack in which a terminal plate, an insulating plate and an end plate are laminated at both ends,
The terminal plate has a terminal joint that protrudes outside through the insulating plate and the end plate that are arranged outward in the stacking direction,
A fuel cell stack, wherein a heater wire is wound around an outer periphery of the terminal joint or an outer periphery of a bus bar connected to the terminal joint.   2. The fuel cell stack according to claim 1, wherein the heater wire forms a ring-shaped heater wound in a cylindrical shape in advance, and the ring-shaped heater is inserted into an outer periphery of the terminal joint. Battery stack. In the fuel cell stack according to claim 1 or 2, on the outer periphery of the terminal joint, a large diameter portion and a small diameter portion are provided coaxially,
The fuel cell stack, wherein the heater wire is wound around the small-diameter portion, and a step between the small-diameter portion and the large-diameter portion is set to a size larger than the diameter of the heater wire.