Method and apparatus for taking out a sealing plate of a fuel cell

A fuel cell sealing plate taking-out method that may include forming an air layer between adjacent sealing plates and taking out a sealing plate from a stack of sealing plates one by one. A protrusion may be formed beforehand at one or more surfaces of each sealing plate. Also, a sealing plate taking-out apparatus having a suction pad and a projection that protrudes more than the suction pad toward the sealing plate. Due to the air layer formed between adjacent sealing plates, it may be possible to take out the sealing plate one by one from the stack of sealing plates.

This is a 371 national phase application of PCT/JP2007/055646 filed 20 Mar. 2007, which claims priority of Japanese Patent Application No. 2006-108735 filed 11 Apr. 2006, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a fuel cell sealing plate taking-out method and apparatus for taking out a fuel cell sealing plate one by one from a stack of fuel cell sealing plates.

BACKGROUND

A fuel cell is constructed from an MEA (Membrane-Electrode Assembly) and separators sandwiching the MEA. A gas diffusion layer is disposed between the MEA and the separator. In the separator, at a power generating region, a fuel gas passage or an oxidant gas passage is formed at a surface of the separator facing the MEA, and a coolant passage is formed at a surface opposite the surface facing the MEA. Further, in the separator, at a non-power generating region located at an outer portion of the separator, a fuel gas manifold, an oxidant gas manifold and a coolant manifold are formed. The fuel gas passage communicates with the fuel gas manifold via a fuel gas inlet/outlet passage, and the oxidant gas passage communicates with the oxidant gas manifold via an oxidant gas inlet/outlet passage. The gas inlet/outlet passage includes a gas passage groove formed at a bottom surface of the gas inlet/outlet passage and a sealing plate disposed at the gas inlet/outlet passage and covers the gas passage groove.

As disclosed in Japanese Patent Publication 2001-110436, the sealing plate is constructed of a stepped plate in order to prevent interference with the diffusion layer.

BRIEF SUMMARY

Certain embodiments of the present invention relate to cases where a fuel cell or fuel cell module is automatically assembled and it may be necessary to take out a sealing plate one by one from a stack of sealing plates supplied and to supply the taken-out sealing plate to a gas inlet/outlet passage of the fuel cell.

Since the sealing plate is constructed of a flat plate, when the sealing plates are stacked, the sealing plates are likely to adhere to each other, because the sealing plates closely contact each other due to a low pressure and/or due to a static electricity at the contact portion. As a result, it may be difficult to separate the sealing plates one by one from each other.

An object of certain embodiments of the present invention is to provide a fuel cell sealing plate taking-out method for taking out a fuel cell sealing plate one by one from a stack of fuel cell sealing plates, a fuel cell sealing plate directly used in the method, and a fuel cell sealing plate taking-out apparatus directly used in the method.

Certain embodiments of the present invention may address the drawbacks discussed above using the following methods and apparatuses:(1) A method for taking out a sealing plate of a fuel cell one by one from a stack of sealing plates, the method comprises steps of:forming an air layer between adjacent sealing plates; andtaking out the sealing plate one by one from the stack of sealing plates while the air layer is formed between the adjacent sealing plates;(2) A method according to item (1) above, wherein in order to form the air layer between the adjacent sealing plates, a protrusion is beforehand formed at an at least one surface of the sealing plate and at a portion of a sealing plate installing place in a direction perpendicular to a gas flow direction at the sealing plate installing place when the sealing plate is installed to the fuel cell;(3) A method according to item (1) above, wherein in order to form the air layer between the adjacent sealing plates, a sealing plate to be taken out is caused to be curved when the sealing plate is sucked and taken out;(4) A method according to item (1) above, further comprises steps of:after taking out the sealing plate, installing the taken-out sealing plate to a fuel cell; andafter taking out the sealing plate and before installing the taken-out sealing plate to the fuel cell, sucking the taken-out sealing plate from opposite sides thereof and stopping conveyance of the sealing plate to the step of installing the sealing plate to the fuel cell when detecting a taking-out of two sealing plates;(5) A sealing plate of a fuel cell directly used in a method for taking out a sealing plate one by one from a stack of sealing plates, the sealing plate comprises:a protrusion beforehand formed at an at least one surface of the sealing plate and at a portion of a sealing plate installing place in a direction perpendicular to a gas flow direction at the sealing plate installing place when the sealing plate is installed to the fuel cell;(6) A sealing plate of a fuel cell according to item (5) above, wherein a position, a width and a height of the protrusion in the sealing plate are determined such that the protrusion of the sealing plate is housed in a gas passage groove of a gas inlet/outlet passage of the separator when the sealing plate is installed to the fuel cell;(7) A sealing plate of a fuel cell according to item (6) above, wherein the width of the protrusion of the sealing plate is equal to or smaller than a width of the gas passage groove;(8) A sealing plate of a fuel cell according to any one of items (5)-(7) above, wherein the sealing plate is made from synthetic resin;(9) A sealing plate of a fuel cell according to item (5) above, wherein the protrusion is formed at a surface of the sealing plate opposite to a surface of the sealing plate facing a bottom surface of the gas passage groove when the sealing plate is installed to the fuel cell;(10) A fuel cell sealing plate taking-out apparatus directly used in a method for taking out a sealing plate one by one from a stack of sealing plates, the apparatus comprises:a suction pad for sucking a central portion of the sealing plate; andprojections located on opposite sides of the suction pad in a longitudinal direction of the sealing plate and projecting toward the sealing plate more than an end of the suction pad;(11) A fuel cell sealing plate taking-out apparatus directly used in a method for taking out a sealing plate one by one from a stack of sealing plates, the apparatus comprises:a two sealing plate taking-out preventing apparatus having a suction plate and a suction pad which suck the sealing plate taken-out from the stack of sealing plates from opposite sides of the taken-out sealing plate, the two sealing plate taking-out preventing apparatus being provided on a sealing plate conveyance passage after the sealing plate is taken out from the stack of fuel cells and before the sealing plate is installed to the fuel cell.

Using the methods and apparatuses discussed above, certain embodiments of the present invention may have the following technical advantages.

According to the method for taking out a sealing plate of a fuel cell according to item (1) above, since the air layer is formed between the adjacent sealing plates, the adjacent sealing plates are not pressed by a pressure difference from outside surfaces toward the contact surface and do not adhere to each other due to static electricity. As a result, it may be possible to ensure separation of the sealing plates one by one from the stack of sealing plates.

According to the method for taking out a sealing plate of a fuel cell according to item (2) above, since the protrusion is formed in at an at least one surface of the sealing plate, in the stack of sealing plates, an air layer can be formed between adjacent sealing plates except the protrusion.

According to the method for taking out a sealing plate of a fuel cell according to item (3) above, since the sealing plate to be taken out is curved, an air layer can be formed between the sealing plate to be taken out and a sealing plate positioned next to the sealing plate to be taken out, when the sealing plate is sucked and taken out.

According to the method for taking out a sealing plate of a fuel cell according to item (4) above, since the taken-out sealing plate is sucked from opposite sides thereof and the sucking pressures on the opposite sides in the case of taking out two sealing plates are different from those in the case of taking out one sealing plate, by detecting the sucking pressure difference, conveyance of the sealing plates in the case of taking out two sealing plates to the next step can be stopped.

According to the sealing plate of a fuel cell according to item (5) above, since the protrusion is formed in the sealing plate, an air layer is formed between adjacent sealing plates except the protrusion. As a result, the adjacent sealing plates are not pressed from the outside surfaces toward the contact surface and the adjacent sealing plates do not adhere to each other due to static electricity, so that it is possible to ensure separation of a sealing plate from the stack of the sealing plates one by one.

According to the sealing plate of a fuel cell according to item (6) above, since the position, the width and the height of the protrusion in the sealing plate are determined such that the protrusion of the sealing plate is housed in a gas passage groove of a gas inlet/outlet passage of the separator, when the sealing plate is installed to the fuel cell separator, the protrusion of the sealing plate is fit into the gas passage groove of the gas inlet/outlet passage of the separator, so that it is possible to determine in position the sealing plate relative to the gas inlet/outlet passage in a direction perpendicular to the gas passage groove (i.e., a gas flow direction at the gas inlet/outlet passage). As a result, a dimensional accuracy of clearances between the longitudinal ends of the sealing plate and side surfaces of the gas inlet/outlet passage facing the longitudinal ends of the sealing plate can be low, so that a manufacturing cost of the sealing plate can be reduced by that dimensional low accuracy. Further, the clearances between the longitudinal ends of the sealing plates and side surfaces of the gas inlet/outlet passage facing the longitudinal ends of the sealing plate can be used as a space for absorbing a bulging-out adhesive.

According to the sealing plate of a fuel cell according to item (7) above, since the width of the protrusion of the sealing plate is nearly equal to the width of the gas passage groove, determination in position of the sealing plate by the protrusion is of a high accuracy.

According to the sealing plate of a fuel cell according to item (8) above, the present invention is further effective, because adhesion of adjacent sealing plates due to static electricity can be prevented by the air layer formed between the adjacent sealing plates by the protrusion, despite that in the case of a synthetic resin sealing plate an adhesion of the adjacent sealing plates due to static electricity is likely to occur.

According to the sealing plate of a fuel cell according to item (9) above, since the protrusion is formed at a surface of the sealing plate opposite to a surface of the sealing plate facing a bottom surface of the gas passage groove when the sealing plate is installed to the fuel cell, air layers can be formed between adjacent sealing plates in the stack of the sealing plates like in the case where the protrusion is formed at a surface of the sealing plate facing a bottom surface of the gas passage groove. In the case where the protrusion is formed at a surface of the sealing plate opposite to a surface of the sealing plate facing a bottom surface of the gas passage groove, the protrusion is embedded in the adhesive located between the separators, a concave may be formed in the separator facing the protrusion if necessary.

According to the fuel cell sealing plate taking-out apparatus according to item (10) above, since the apparatus comprises the suction pad for sucking a central portion of the sealing plate, and the projections, it is possible to deform the sealing plate to be taken out in the form of an arch, so that an air layer can be formed between the sealing plate to be taken out and the next sealing plate.

According to the fuel cell sealing plate taking-out apparatus according to item (11) above, since the apparatus comprises the suction plate and the suction pad, taking out of two sealing plates can be detected by sucking the sealing plate or plates taken out from the stack of sealing plates from opposite sides thereof, and conveyance of the two sealing plates to the next step can be stopped.

The invention may be embodied by numerous methods, systems, devices, and products, and the description and drawings provided herein are examples of the invention. Other embodiments, which incorporate some or all of the steps and features, are also possible.

DETAILED DESCRIPTION

A method for taking out a fuel cell sealing plate (which includes a two sealing plate taking-out preventing method), a fuel cell sealing plate directly used in conducting the method, and a fuel cell sealing plate taking-out apparatus (which includes a two sealing plate taking-out preventing apparatus), respectively, according to certain embodiments of the present invention will be explained with reference toFIGS. 1-21. The fuel cell sealing plate will be referred to as a sealing plate.

FIGS. 1-12illustrate a first embodiment (a sealing plate taking-out method, a sealing plate, and a sealing plate taking-out apparatus according to the first embodiment) of the invention.

FIG. 14illustrates a second embodiment (a sealing plate taking-out method, a sealing plate, and a sealing plate taking-out apparatus according to the second embodiment) of the invention.

FIGS. 15-18illustrate a third embodiment (a sealing plate taking-out method, a sealing plate, and a sealing plate taking-out apparatus according to the third embodiment) of the invention.

FIGS. 19-21illustrate a fuel cell structure applicable to any embodiment of the present invention.

Structures common to all embodiments of the present invention are denoted with the same references throughout all embodiments of the present invention.

First, structures common to all embodiments of the present invention will be explained with reference toFIGS. 19-21.

A fuel cell to which the present invention is applied is a solid polymer electrolyte membrane-type fuel cell10. The fuel cell10is installed to a fuel cell vehicle. The fuel cell10may be used for other than a vehicle.

As illustrated inFIGS. 19-21, the solid polymer electrolyte membrane-type fuel cell10includes a layered structure of a membrane-electrode assembly19(MEA) and a separator18.

The membrane-electrode assembly19includes an electrolyte membrane11made from an ion-exchange membrane, a first electrode (i.e., anode)14made from a catalyst layer disposed on one side of the electrolyte membrane11and a second electrode (i.e., cathode)17made from a catalyst layer. A diffusion layer13is disposed between the membrane-electrode assembly19and the separator18on the side of the anode. A diffusion layer16is disposed between the membrane-electrode assembly19and the separator18on the side of the cathode.

The membrane-electrode assembly19and the separator18are layered to construct the fuel cell10. A plurality of fuel cells are stacked to construct a stack of fuel cells. A terminal20, an insulator21and an end plate22are disposed at each end of the stack of fuel cells. The opposite end plates22are fixed to a fastening member (for example, a tension plate24) extending in a fuel cell stacking direction by a bolt and nut25. The stack of fuel cells are fastened in the fuel cell stacking direction to construct a fuel cell stack23.

In the separator18located on the anode side of the fuel cell10, at a power generating region51, a fuel gas passage27for supplying fuel gas (i.e., usually, hydrogen) to the anode14is formed at the surface facing the MEA. In the separator18located on the cathode side of the fuel cell10, at the power generating region51, an oxidant gas passage28for supplying oxidant gas (i.e., usually, air) to the cathode17is formed at the surface facing the MEA. Further, in the separator18, a coolant passage26for supplying coolant (i.e., usually, water) is formed at a surface opposite the surface where the gas passages27and28are formed. In the separator18, at a non-power generating region52, a fuel gas manifold30, an oxidant gas manifold31and a coolant manifold29are formed.

The fuel gas manifold30communicates with the fuel gas passage27via a gas inlet/outlet passage34, and the oxidant gas manifold31communicates with the oxidant gas passage28via the gas inlet/outlet passage34. The coolant manifold29communicates with the coolant passage26.

At the anode14of each fuel cell10, electrolytic dissociation to exchange hydrogen to hydrogen ion (i.e., proton) and electron, and the electron moves in the electrolyte membrane11to the cathode17. At the cathode17, water is produced and power is generated according to the following equation from oxygen and the hydrogen ion and electron which is generated at the anode of the adjacent fuel cell and comes to the cathode of the instant fuel cell, or is generated at the anode of the fuel cell located at a first end of the fuel cell stack and comes via an outside circuit to the cathode of the fuel cell located at a second end of the fuel cell stack.
At the anode: H2→2H++2e−
At the cathode: 2H++2e−+(½)O2→H2O

Each fluids are sealed from each other and from outside. A first seal member32seals between the two separators18sandwiching the MEA19, and a second seal member33seals between adjacent fuel cells10.

The first seal member32is a sealant made from an adhesive (sealing adhesive), and the second seal member33is a rubber seal member made from silicone rubber, fluorine rubber, or EPDM (ethylen-propylen-dien rubber). Both the first seal member32and the second seal member33may be made from sealing adhesive or rubber seal material.

As illustrated inFIG. 21andFIG. 5, one or more (usually, a plurality of) concave gas passage grooves35are formed at the gas inlet/outlet passage34. At the gas inlet/outlet passage34, a sealing plate36is disposed so as to cover the gas passage groove35. In the separator, a step37having a depth equal to a thickness of the sealing plate36is formed for receiving end portions of the sealing plate36therein. When the step37receives therein the end portion of the sealing plate36, a surface of the separator18and a surface of the sealing plate36are located in the same plane. When the sealing plate36is disposed in the gas inlet/outlet passage34, the gas passage groove35is covered with the sealing plate36and constructs a tunnel-like passage.

The sealing plate36is rectangular and is disposed such that a longitudinal direction of the rectangle is directed in a gas passage width direction of the gas inlet/outlet passage34. The gas passage groove35extends in a width direction of the sealing plate36. Since gas flows in the gas passage groove35, the width direction of the sealing plate36coincides with the gas flow direction at the gas inlet/outlet passage34, and the longitudinal direction of the sealing plate36coincides with a direction perpendicular to the gas flow direction at the gas inlet/outlet passage34.

The sealing plate36comprises a flat plate (which may include a stepped flat plate). When the diffusion layers13,16overlap with the sealing plate36, the sealing plate36comprises a stepped flat plate having a step38for receiving the diffusion layers13,16therein and having a thickness equal to the thickness of the diffusion layers13,16. The step38extends in the longitudinal direction of the sealing plate36. A surface of the sealing plate opposite the surface of the sealing plate faces a bottom surface of the gas inlet/outlet passage34and is coated with the first seal member (e.g., adhesive) and faces a separator18having an opposite polarity of the same fuel cell (i.e., a cathode side separator when the sealing plate is disposed at the anode side separator, and an anode side separator when the sealing plate is disposed at the cathode side separator).

The sealing plate36is made from synthetic resin, but is not limited to synthetic resin. The sealing plate36may be made from rubber, metal and carbon, etc.

As illustrated inFIGS. 11-17, in order to determine a position of the sealing plate36and dispose the sealing plate in the gas inlet/outlet passage34of the fuel cell10using an automatic apparatus, firstly a sealing plate36is taken out one by one from a stack61of sealing plates supplied, for example, by sucking the sealing plate by a suction pad62of a sealing plate taking-out apparatus60. Then, the taken-out sealing plate36is determined in position at a position determining station65, and the sealing plate36determined in position is conveyed and supplied to an assembly step of the fuel cell10where the sealing plate is installed to the fuel cell10.

It may be necessary to take out the sealing plate36from the stack61of sealing plates one by one by sucking the sealing plate by the suction pad62. When the sealing plate36is flat, as illustrated comparatively, in examples ofFIGS. 11 and 13, it is sometimes difficult to take out the sealing plate36from the stack61of sealing plates one by one (i.e., as a result, two sealing plates are taken out). This is because when sealing plates are layered, adjacent sealing plates closely contact each other, and a pressure lower at the contact surface is likely lower than that at an outside surface (e.g., a vacuum) and/or a static electricity is generated at the contact surface, so that the adjacent sealing plates adhere to each other.

The fuel cell sealing plate taking-out method, the sealing plate36directly used for conducting the method, and the sealing plate taking-out apparatus60according to certain embodiments of the present invention make it possible to take out the sealing plate36from the stack61of sealing plates one by one.

More particularly, as illustrated inFIG. 12andFIG. 14, a portion of the fuel cell sealing plate taking-out method common to each embodiment of the present invention is a method for the sealing plate36from the stack61of sealing plates one by one, wherein an air layer63is formed between adjacent sealing plates36and in that state the sealing plate36is taken out one by one from the stack61of sealing plates. A method for forming the air layer63differs according to each embodiment. The method according to certain embodiments of the present invention may include a method where when taking out two sealing plates is detected, the taking out of two sealing plates is omitted (FIG. 16). Comparatively, in the conventional method, as illustrated, for example, inFIG. 13, an air layer is not formed between adjacent workpieces36′ and a vacuum is generated between the adjacent workpieces36′.

Some of the effects and technical advantages obtained in the portion of the fuel cell sealing plate taking-out method common to each embodiment of the present invention will be explained. Since the air layer63is formed between the adjacent sealing plates36, the adjacent sealing plates36are not pressed from outside surfaces to the contact surface thereof by a pressure difference. Further, the adjacent sealing plates36do not adhere to each other due to a static electricity. As a result, it is possible to take out the sealing plate36from the stack61of sealing plates one by one.

In the case where the sealing plate36is made from synthetic resin, the static electricity is likely to collect at the surface, so that the adjacent sealing plates36are apt to adhere to each other due to the static electricity. By forming the air layer63between the adjacent sealing plate36, adhesion of the adjacent sealing plates36due to the static electricity can be suppressed, so that the prevention of adhesion due to the air layer63becomes further effective.

Next, portions of the sealing plate taking-out method, the sealing plates36directly used in conducting the method, and the sealing plate taking-out apparatus60directly used in conducting the method, unique to each embodiment of the present invention will be explained.

[Method for Taking Out the Sealing Plate36According to a First Embodiment]

In the fuel cell sealing plate taking-out method according to the first embodiment of the present invention, in order to form the air layer63between adjacent sealing plates36of the stack1of sealing plates, a protrusion39is formed as illustrated inFIG. 4andFIG. 11. The protrusion39is formed at an outermost surface of an at least one surface of each sealing plate36. (The at least one surface may be a surface40of the sealing plate facing a bottom surface of the gas inlet/outlet passage34, or a surface41of the sealing plate opposite the surface40, when the sealing plate is disposed at the gas inlet/outlet passage34. The outermost surface is a surface of the sealing plate other than a surface of a recess receding by the step38from the outermost surface.) The protrusion39is formed at a portion of the sealing plate in the direction perpendicular to the gas flow direction at the sealing plate installing portion (i.e., the gas inlet/outlet passage34) of the fuel cell such that the protrusion39protrudes from the surface40,41. InFIGS. 1-10, the region of the protrusion39is shown by a hatching, which is not a hatching for a cross section.

Some of the effects and technical advantages of the fuel cell sealing plate taking-out method according to the first embodiment of the present invention will be explained. Since the protrusion39is formed at the at least one surface40,41of each sealing plate36, the air layer63can be formed between adjacent sealing plates36of the stack61of sealing plates except a top of the sealing plate36. Due to the air layer63, a vacuum (a pressure lower than the outermost surface) is not produced between the adjacent sealing plates36, and adhesion due to a static electricity is suppressed, so that it is possible to take out the sealing plate one by one from the stack61of sealing plates.

[Sealing Plate36according to a First Embodiment]

As illustrated inFIGS. 1-11, the fuel cell sealing plate36according to the first embodiment of the present invention has a protrusion39formed at a least one surface40,41of the sealing plate36. The protrusion39is formed at one portion of the at least one surface of the sealing plate in the direction perpendicular to the gas flow direction (the longitudinal direction of the gas passage groove35) at the fuel cell sealing plate installing portion.

Preferably, the sealing plate36is made from synthetic resin, but may be made from rubber or metal. Preferably, the protrusion39may be formed integrally with the sealing plate36, but may be formed separately from the sealing plate36and fixed to the sealing plate36by an adhesive, etc.

A position, a number, a width (i.e., a width in the longitudinal direction of the sealing plate36) and a height (i.e., a height from the surface40,41) of the protrusion39in the sealing plate36are determined such that the protrusion39of the sealing plate36is housed in the gas passage groove35of the gas inlet/outlet passage34of the separator18when the sealing plate36is installed to the fuel cell10.

More particularly, the width of the protrusion39of the sealing plate36is substantially equal to the width of the gas passage groove35. (As illustrated inFIG. 5, since the protrusion fits into the groove35, the width of the protrusion is slightly smaller than the width of the groove35.) Due to this, the protrusion39can fit in the gas passage groove35, and can be used for positional determination of the sealing plate36in the longitudinal direction of the gas inlet/outlet passage34.

The number of protrusion39is not limited to one, and a plurality of protrusions39can be provided as illustrated inFIG. 6. A shape of the protrusion39in the plan view thereof may be a circle, an elongated circle and a polygon (e.g., a triangle).

A cross-sectional shape of the protrusion39in a plane perpendicular to the surface40,41may be a rectangle or a shape other than the rectangle (e.g., an arc (FIG.8)), a triangle (FIG. 9) or a trapezoid. When the cross-sectional shape of the protrusion is a rectangle or a trapezoid, the top of the protrusion39is a flat plane and plane-contacts the adjacent sealing plate when the sealing plates are layered. When the cross-sectional shape of the protrusion is an arc or a triangle, the top of the protrusion39is a point and point-contacts the adjacent sealing plate when the sealing plates are layered.

As illustrated inFIG. 10, the protrusion39may be formed at the surface41of the sealing plate36opposite to the surface40of the sealing plate36facing the bottom surface of the gas passage groove35when the sealing plate36is installed to the fuel cell. In this case, the protrusion39is embedded in the adhesive contacting the surface41of the sealing plate36. At a portion of the adjacent separator18facing the protrusion39, a concave may be formed for preventing interference with the protrusion39.

Some of the effects and technical advantages of the fuel cell sealing plate36according to the first embodiment of the present invention will be explained. Since the protrusion39is formed in the sealing plate36, the air layer63is formed between the adjacent sealing plates36except the protrusion39. Due to the air layer63, a vacuum (a pressure lower than the outermost surface) is not produced between the adjacent sealing plates36, and adhesion due to a static electricity is suppressed, so that it is possible to separate and take out the sealing plate36one by one from the stack61of sealing plates.

Since the position, the width and the height of the protrusion39in the sealing plate36are determined such that the protrusion39of the sealing plate36is housed in the gas passage groove35of the gas inlet/outlet passage34of the separator, when the sealing plate36is installed to the fuel cell separator18, the protrusion39of the sealing plate36is fit into the gas passage groove35of the gas inlet/outlet passage34of the separator18, so that it is possible to determine in position the sealing plate36relative to the gas inlet/outlet passage34in a direction perpendicular to the gas passage groove35(i.e., a gas flow direction at the gas inlet/outlet passage34). As a result, a dimensional accuracy of clearances between the longitudinal ends of the sealing plate36and side surfaces of the gas inlet/outlet passage34facing the longitudinal ends of the sealing plate can be low as compared with a case where the sealing plate is determined in position by contacting the longitudinal end of the sealing plate with the side surfaces of the gas inlet/outlet passage34facing the longitudinal ends of the sealing plate. As a result, a manufacturing cost of the sealing plate36can be reduced by that dimensional low accuracy. Further, the clearances42between the longitudinal ends of the sealing plate36and side surfaces of the gas inlet/outlet passage34facing the longitudinal ends of the sealing plate can be used as a space for absorbing a bulging-out adhesive32.

Since the width of the protrusion39of the sealing plate36is nearly equal to the width of the gas passage groove35, determination in position of the sealing plate by the protrusion36is of a high accuracy.

When the sealing plate36is made from synthetic resin, static electricity is likely to collect at the surface of the sealing plate36. As a result, the adjacent sealing plates36are likely to adhere to each other due to the static electricity. However, in certain embodiments of the present invention, since the air layer63due to the protrusion39is formed between the adjacent sealing plates36, the adhesion due to the static electricity is suppressed, and it is possible to take out the sealing plate one by one.

When the protrusion39is formed at the surface41of the sealing plate36opposite to the surface40of the sealing plate36facing the bottom surface of the gas passage groove35when the sealing plate36is installed to the fuel cell, the air layer63can be formed between the adjacent sealing plates36in the stack61of sealing plates, as in the case where the protrusion39is formed at the surface40of the sealing plate36facing the bottom surface of the gas passage groove35. In the case where the protrusion39is formed at the surface41of the sealing plate36opposite to the surface40of the sealing plate36facing the bottom surface of the gas passage groove35, the protrusion39is embedded in the adhesive contacting the surface41of the sealing plate36. By forming a concave for preventing interference with the protrusion39if necessary, the sealing effect by the adhesive32can be almost not affected by the protrusion39.

[Sealing Plate Taking-out Method according to a Second Embodiment]

A sealing plate taking-out method according to a second embodiment of the present invention is a method where, as illustrated in, for example,FIG. 14, in order to form the air layer63between the adjacent sealing plates36, a sealing plate36to be taken out is caused to be curved when the sealing plate is sucked and taken out. The sealing plate36positioned next to the sealing plate to be taken out is not curved. Contrarily, in a comparison example ofFIG. 13, the workpiece36′ is not caused to be curved when sucked by a sucking pad62′, and a place between the adjacent workpieces36′ is at a vacuum or a near vacuum.

Some of the effects and technical advantages of the sealing plate taking-out method according to a second embodiment of the present invention will be explained. Since the sealing plate36to be taken out is caused to be curved, the air layer63can be formed between the sealing plate36to be taken out and the sealing plate positioned next to the sealing plate to be taken out. Due to the air layer63, the adjacent sealing plates36are not pressed from the outside surfaces toward the contact surface thereof, and adhesion of the adjacent sealing plates due to a static electricity is suppressed. As a result, it is possible to separate and take out the sealing plate36surely one by one from the stack61of sealing plates (without taking out two sealing plates).

[Sealing Plate Taking-Out Apparatus According to a Second Embodiment]

A sealing plate taking-out apparatus60according to the second embodiment of the present invention is, as illustrated in, for example,FIG. 12, an apparatus directly used in taking out the fuel cell sealing plate36from the stack61of sealing plates. The apparatus comprises a suction pad62for sucking a central portion of the sealing plate36, and projections64located on opposite sides of the suction pad62in the longitudinal direction of the sealing plate36and projecting toward the sealing plate36more than an end of the suction pad62.

Some of the effects and technical advantages of the sealing plate taking-out apparatus60according to the second embodiment of the present invention will be explained. Since the sealing plate taking-out apparatus60comprises the suction pad62for sucking a central portion of the sealing plate, and the projections64pushing the sealing plate36at a portion other than the sucking portion of the sealing plate by the suction pad62, the suction pad62and the projections64can bend the sealing plate36to be taken out in the form of an arch. As a result, between the sealing plate36to be taken out and the sealing plate36positioned next to the sealing plate to be taken out, the air layer63a thickness of which becomes largest at the central portion of the longitudinal direction of the sealing plate36can be formed. Due to the air layer63, it is possible to ensure separation and take out the sealing plate36one by one from the stack61of sealing plates (without taking out two sealing plates).

[Sealing Plate Taking-Out Method According to a Third Embodiment, Including Stopping Supply in the Case of Taking Out Two Sealing Plates]

In the fuel cell sealing plate taking-out method according to the third embodiment of the present invention, after taking out the sealing plate36and before installing the taken-out sealing plate to a fuel cell, the taken-out sealing plate36is sucked from opposite surfaces thereof. When taking out of two sealing plates is detected, conveyance of the sealing plates36to the assembly step of the fuel cells is stopped.

In more detail, as illustrated inFIGS. 15-17, after taking out the sealing plate36and before installing the taken-out sealing plate to a fuel cell, at a sealing plate position determining station65(where using a position determining plate66, a position of the sealing plate36is determined in the longitudinal direction and/or the width direction of the sealing plate36), the sealing plate36taken out from the stack61of sealing plates and conveyed to the sealing plate position determining station65is sucked from the opposite sides thereof (e.g., from an upper side and a lower side of the sealing plate, or from horizontally opposite sides of the sealing plate), using a suction pad62and a suction plate67. The suction by the suction pad62and/or the suction plate67is different between the case of taking out one sealing plate and the case of taking out two sealing plates. When taking out two sealing plates is detected using the suction difference, conveyance of the sealing plates36to the assembly step80of the fuel cell is stopped. Usually, the suction force of the suction plate67is increased, and when the suction of the suction pad62operates to ON, taking out of two sealing plates is deemed to happen, and the conveyance and supply of the sealing plates36to the next step (the assembly step80of the fuel cell) is stopped. InFIGS. 15 and 16, arrow S shows suction. Further, inFIG. 16, arrow R shows raise of the suction pad62.

FIG. 18shows one example of a flow of steps of fuel cell sealing plate taking-out method including a step for preventing taking out of two sealing plates.

InFIG. 18, at step101, a routine for taking out one sealing plate36from the stack61of sealing plates is begun. Taking out one sealing plate only is conducted by proceeding to step102where the protrusion39formed at the sealing plate36is used, or proceeding to step103where the sealing plate36is bent in the form of an arch. Any one of steps102and103may be adopted. Then, the routine proceeds to step104for preventing taking out of two sealing plates. At step105, a sealing plate36is placed on the suction plate67if the position determining station65. Proceeding to step106, both suction of the suction pad62which is a taking-out tool and suction of the suction plate67are made ON. Proceeding to step107, the suction pad62which is a taking-out tool is raised. Proceeding to step108, a suction pressure of the suction pad62which is a taking-out tool is examined so that whether a sucked workpiece (a second workpiece in the case of taking out two sealing plates) exists or not is confirmed. When a workpiece sucked by the suction pad62exists, the suction pressure of the suction pad62is greater than the atmospheric pressure, while when a workpiece sucked by the suction pad62does not exist, the suction pressure of the suction pad62is zero (the atmospheric pressure).

When a workpiece sucked does not exist, proceeding from step108to step109, after confirming at step109that a workpiece sucked does not exist, at step110the suction pad62conducts the next operation (where the suction plate67makes its suction OFF and the suction pad62conveys and supplies the sealing plate to the assembly step80of the fuel cell). At step111the routine is completed and returns to step101where the next taking-out of the next workpiece begins.

When a workpiece sucked exists, proceeding from step108to step112, after confirming at step112that a workpiece sucked (a second sealing plate) exists, at step113generation of NG is confirmed. Then, at step114, ejecting out the second sealing plate36(corresponding to step68ofFIG. 17) is conducted, and then the routine returns to step101where the next taking-out of the next workpiece begins.

According to the fuel cell sealing plate taking-out method according to the third embodiment of the present invention, since the taken-out sealing plate36is sucked from opposite sides thereof, taking out two sealing plates can be detected by detecting the suction pressures using the routine ofFIG. 18, because the suction pressures on the opposite sides differ from each other between in the case where two sealing plates are taken out and in the case where one sealing plate is taken out. When taking out of two sealing plates is detected, conveyance and supply of the sealing plates taken out to the next step can be stopped. As a result, incorrect installing of the sealing plate36can be prevented.

[Sealing Plate Taking-Out Apparatus According to a Third Embodiment]

A fuel cell sealing plate taking-out apparatus60according to a third embodiment of the present invention directly used in conducting the sealing plate taking-out method includes an apparatus for preventing taking out two fuel cell sealing plates disposed at a portion of a sealing plate conveyance route after taking out a sealing plate36from the stack61of sealing plates and before installing the taken-out sealing plate to a fuel cell. The two sealing plate taking-out preventing apparatus includes the suction plate67and the suction pad62which suck the sealing plate taken-out from the stack61of sealing plates from opposite sides thereof (for example, from an upper side and a lower side of the sealing plate).

According to the fuel cell sealing plate taking-out apparatus60according to the third embodiment of the present invention, since the apparatus includes the suction plate67and the suction pad62, taking out two sealing plates can be detected by sucking the taken-out sealing plates from the opposite sides thereof (e.g., from the upper side and the lower side of the taken-out sealing plates), and conveyance and supply of the taken-out two sealing plates to the next step (fuel cell assembly step80) can be stopped.

The examples described herein are merely illustrative, as numerous other embodiments may be implemented without departing from the spirit and scope of the exemplary embodiments of the present invention. Moreover, while certain features of the invention may be shown on only certain embodiments or configurations, these features may be exchanged, added, and removed from and between the various embodiments or configurations while remaining within the scope of the invention. Likewise, methods described and disclosed may also be performed in various sequences, with some or all of the disclosed steps being performed in a different order than described while still remaining within the spirit and scope of the present invention.