JP2016195065A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve impact resistance and vibration resistance of fuel cells regardless of a temperature environment of the fuel cells.SOLUTION: A fuel cell in which a laminate including a plurality of laminated electric cells is accommodated in a case includes a restraining member arranged between a side face of the laminate along the lamination direction and the inner face of the case. The thickness of the restraining member in a state where the restraining member is not accommodated in the case is less than a gap between the side face of the laminate and the inner face of the case under a predetermined pressurizing condition higher than an atmospheric condition, and is equal to or more than the gap under the atmospheric condition.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a fuel cell having a stack structure in which a plurality of single cells are stacked.

  In a fuel cell, for example, a polymer electrolyte fuel cell, a reactive gas (a fuel gas containing hydrogen and an oxidizing gas containing oxygen) is respectively applied to two electrodes (a fuel electrode and an oxygen electrode) facing each other with an electrolyte membrane interposed therebetween. By supplying and causing an electrochemical reaction, the chemical energy of the substance is directly converted into electrical energy. As a main structure of such a fuel cell, a so-called stack structure is known in which unit cells composed of a power generation body including a substantially flat electrolyte membrane are stacked and fastened in the stacking direction.

  By the way, the fuel cell may be required to have sufficient resistance against external impacts and vibrations depending on its use conditions. In order to improve the impact resistance and vibration resistance of a fuel cell, a technology is known in which a plate is provided to cover a side surface along the stacking direction of a stack of unit cells, and a buffer member is disposed between the plate and the stack. (For example, Patent Document 1). The buffer member is configured by a hollow member in which air is sealed. In this fuel cell, the buffer member is designed to be thin at room temperature to facilitate the assembly of the fuel cell, and when the fuel cell is used, the air inside the buffer member in accordance with the temperature rise of the fuel cell By suppressing the movement of each unit cell of the laminate, the impact resistance and vibration resistance of the fuel cell can be obtained.

JP 2003-203670 A

  However, in the buffer member, for example, when the fuel cell is in a low temperature state, such as when starting in a low temperature environment, the internal air contracts, and the movement of each unit cell cannot be suppressed. There exists a subject that the impact resistance of a battery and vibration resistance fall. This facilitates the assembly of the fuel cell and suppresses the movement of each single cell contained in the laminate (also referred to as a “fuel cell stack”) regardless of the temperature environment of the fuel cell, thereby improving the impact resistance of the fuel cell. It has been desired to improve the property and vibration resistance.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

(1) According to one aspect of the present invention, there is provided a fuel cell in which a stacked body including a plurality of stacked single cells is accommodated in a case. The fuel cell includes a restraining member disposed between a side surface along the stacking direction of the stacked body and an inner surface of the case. The thickness of the restraining member in a state not accommodated in the case is less than a gap between the side surface of the laminate and the inner surface of the case under a predetermined pressurizing condition higher than an atmospheric pressure condition. Yes, and above the gap under the atmospheric pressure condition.
According to this embodiment, for example, after the laminated body is accommodated in the case, the restraint member is disposed between the side surface along the lamination direction of the laminated body and the inner surface of the case under a pressurized condition, and then the atmospheric pressure condition By returning to the bottom, the laminate can be easily restrained. In addition, the stack can be restrained regardless of the temperature environment of the fuel cell, and the movement of a plurality of single cells included in the stack can be suppressed, improving the shock resistance and vibration resistance of the fuel cell. Can be made.

  In addition to the above, the present invention can be realized in various forms including a device invention such as a vehicle or a moving body equipped with the fuel cell of the above-described form, a method invention such as a method of manufacturing or installing a fuel cell. It is possible.

It is a perspective view which shows schematic structure of the fuel cell in embodiment. It is a disassembled perspective view which shows schematic structure of the fuel cell in embodiment. It is explanatory drawing which shows the method of accommodation and fastening in the case of two end plates and a laminated body. It is explanatory drawing which shows the method of arrange | positioning a restraint member in an unconstrained fastening body. It is explanatory drawing which shows the method of restraining a laminated body with the restraint member arrange | positioned in an unconstrained fastening body.

A. Embodiment:
FIG. 1 is a perspective view showing a schematic configuration of a fuel cell 100 as an embodiment. FIG. 2 is an exploded perspective view of the fuel cell 100 shown in FIG. As shown in FIGS. 1 and 2, the fuel cell 100 includes a stacked body 10, two end plates 20 </ b> A and 20 </ b> B, a pressure plate 30, four restraining members 40, and two insulators 50. The case 60 is provided. In FIG. 1, for convenience of illustration, the case 60 is shown in a transparent state, and the insulator 50 is indicated by a broken line.

  The stacked body 10 includes a battery stack in which a plurality of unit cells 11 are stacked, two current collecting plates 12, and two insulating plates 13. The two current collecting plates 12 are arranged so as to sandwich the battery stack at both ends in the stacking direction (X direction) of the battery stack. The two insulating plates 13 are respectively arranged outside the current collector plate 12. The insulating plate 13 is formed of an insulating member such as resin. The current collector plate 12 is formed of a gas impermeable conductive member such as dense carbon or a copper plate.

  Although not shown, the unit cell 11 is composed of a membrane electrode assembly (hereinafter also referred to as “MEA”) as a power generator and a separator for sandwiching the MEA. The MEA is composed of an electrolyte membrane, catalyst electrodes disposed on both surfaces of the electrolyte membrane, and diffusion layers respectively disposed between the catalyst electrode and the separator. The electrolyte membrane is an ion exchange membrane formed of a solid polymer material such as a fluorine resin. The catalyst electrode includes a catalyst (for example, platinum or a platinum alloy), and is formed by supporting these catalysts on a conductive carrier (for example, carbon particles). The diffusion layer functions as a flow path for the reaction gas (oxidizing gas or fuel gas), and is a porous body made of, for example, metal or carbon.

  The first end plate 20A, the second end plate 20B, and the pressure plate 30 are sandwiching members for sandwiching the stacked body 10 in the stacking direction. The end plates 20A and 20B and the pressure plate 30 are made of metal such as steel in order to ensure rigidity. Similarly, the case 60 is made of metal such as steel or ceramics in order to ensure rigidity.

  As shown in FIGS. 1 and 2, the first end plate 20 </ b> A is coupled to the case 60 by a bolt 70 so as to cover the opening 61 of the case 60 in a state where the stacked body 10 is sandwiched. Further, the pressure plate 30 is pressed by the load adjusting screw 64 in a state where the stacked body 10 is sandwiched. The load adjusting screw 64 presses the pressure plate 30 by being screwed into a plurality (six in this example) of screw holes 63 provided on the case side surface 62 facing the opening 61. Thereby, the two end plates 20 </ b> A and 20 </ b> B and the stacked body 10 are accommodated in the case 60 in a state of being fastened to the case 60. A method of housing and fastening the two end plates 20A and 20B and the laminated body 10 in the case 60 will be described later.

  The two insulators 50 are insulating members for insulating the case 60 and the laminated body 10 so that the laminated body 10 is sandwiched and covered from the vertical direction (Z direction) perpendicular to the laminating direction (X direction). It is disposed in contact with the inner surface of the case 60. The insulator 50 is formed of various members that ensure rigidity and insulation, such as an insulating resin, insulating ceramics, a metal that has been subjected to an insulating process by coating an insulating material, and the like.

  The four restraining members 40 are arranged such that the side surfaces along the stacking direction of the stacked body 10 and the inner surface of the insulator 50 cover the four corners that are the ends of the four side surfaces along the stacking direction of the stacked body 10. It is the L-shaped member arrange | positioned between. The restraining member 40 is a restraining function for suppressing the movement of each unit cell 11 included in the laminate 10 and a buffering function for suppressing impact and vibration on the fuel cell and improving impact resistance and vibration resistance. It is a member that exhibits When the inner surface of the case 60 is insulated by application of an insulating material or the like, or when the case 60 is formed of an insulating member, the insulator 50 can be omitted. 40 is installed between the side surface along the stacking direction of the stacked body 10 and the inner surface of the case 60. As will be described later, the four restraining members 40 are installed by being inserted from the four insertion holes 65 provided in the case side surface 62 after the stacked body 10 is accommodated in the case 60.

  In addition to the screw hole 63 and the insertion hole 65, two through holes 67 are provided on the case side surface 62 facing the opening 61. Each insertion hole 65 is provided with an insertion cover 66 for closing the insertion hole, and each through hole 67 is provided with a ventilation cover 68. Note that the two through holes 67 are, as will be described later, insertion holes for pressure shafts for pressing the pressure plate 30 when the laminated body 10 sandwiched between the two end plates 20A and 20B is fastened to the case 60. Used as

  FIG. 3 is an explanatory view showing a method for housing and fastening the laminated body 10 sandwiched between the two end plates 20A and 20B into the case 60. As shown in FIG. FIG. 3 schematically shows a state in which the side surface (corresponding to the front side surface in the Y direction in FIG. 1) of the case 60 and the insulator 50 covering the laminated body 10 is broken for convenience of illustration. .

  As shown in FIG. 3A, the first end plate 20A is supported by the support portion 92 of the fastening jig, and the laminate 10 sandwiched between the two end plates 20A and 20B is connected to the support portion 92 and the pressure plate. 30, and pressed from the pressure plate 30 side by the pressure shaft 94. The pressure shaft 94 presses the pressure plate 30 through the through hole 67 of the case 60 placed on a conveyance jig (not shown). The insulator 50 is disposed in advance in the case 60 so as to contact the inner surface of the case 60. Thereby, the set predetermined load (for example, a load within a range of 10 kN to 100 kN) is applied to the stacked body 10 sandwiched between the two end plates 20A and 20B.

  While maintaining the state where the load is applied, as shown in FIG. 3B, the flange 60 on the outer side of the opening 61 is the flange of the first end plate 20A. The first end plate 20 </ b> A and the case 60 are fastened with bolts 70 until they come into contact with 21. Then, after the load adjustment screw 64 is screwed into the screw hole 63 of the case side surface 62 facing the opening 61 of the case 60 until it contacts the pressure plate 30, the load applied by the pressure shaft 94 is eliminated, The load can be maintained by the load adjusting screw 64. Thereby, the laminate 10 sandwiched between the two end plates 20 </ b> A and 20 </ b> B can be accommodated in the case 60 and fastened to the case 60. In the following, the laminated body 10 sandwiched between the two end plates 20A and 20B is housed in the case 60 and fastened to the case 60, but the structure in a state where the restraining member 40 is not yet installed. It is also called “unconstrained fastening body 80”.

  FIG. 4 is an explanatory view showing a method of arranging the restraining member 40 in the unconstrained fastening body 80. As shown in FIG. 4A, the unconstrained fastening body 80 and the four restraining members 40 are arranged in the pressurized container 110. 4A is a state in which the case 60 covering the unconstrained fastening body 80 and the side surface on the front side of the paper surface of the insulator 50 (corresponding to the front side surface in the Y direction in FIG. 1) are broken for convenience of illustration. Is schematically shown.

  As described above, the restraining member 40 is a member that exhibits a restraining function for restraining the movement of each unit cell 11 of the stacked body 10 and a buffering function for restraining impact and vibration. Further, the restraining member 40 is a member having a property that the volume is contracted by pressurization. As the restraining member 40, various members having porous and dilatancy characteristics having unconnected pores can be used. “Dilatancy characteristics” is a type of nonlinear viscoelasticity that behaves like a solid against a sudden external force and acts like a liquid against a slow external force, for example, when a large impact is applied instantaneously. It has such a characteristic that it hardens.

  As an example, the constraining member 40 can be a member made of a polymer base material that imparts dilatancy characteristics or a porous material containing an organic material. For example, the restraining member 40 can be composed of a composite material in which a polymer base material that imparts dilatancy characteristics is contained in pores of a cellular foam such as a polyurethane foam or a cellulose foam.

  Examples of the polymer base material that imparts dilatancy characteristics include silicone bouncing putties. Here, the silicone bouncing putty is a boron-containing siloxane polymer obtained by polymerizing dimethylsiloxane using boric acid as a catalyst. This material is a shear-thickening material that is sensitive to deformation speed, and becomes a viscous flow at low-speed strain deformation, but sufficiently increases viscosity at high-speed strain deformation.

  In addition, examples of the organic material imparting dilatancy characteristics include a liquid or gel substance that is a dispersion of solid particles in a viscous fluid. The organic material can be used as the restraining member 40 by encapsulating an organic material imparting dilatancy characteristics inside the resin by processing the resin material into a hollow body or a porous body of foam. The polymer-based material imparting dilatancy characteristics or the porous material containing an organic substance used as the restraining member 40 is described in, for example, International Publication No. 2012/081173, the disclosure of which is incorporated by reference. .

  The thickness of the restraining member 40 in a state where it is not accommodated in the case 60 is a state (hereinafter, “900 hpa to 1100 hpa (0.88 atm to 1.08 atm)) under atmospheric pressure, which is a normal use environment of the fuel cell. (Also referred to as “normal pressure state”) between the laminate 10 of the unconstrained fastening body 80 and the inner surface of the case 60 (specifically, the inner surface of the insulator 50 disposed so as to contact the inner surface of the case 60). The thickness is set to be equal to or greater than the length of the gap 81.

  When the restraining member 40 is disposed in the unconstrained fastening body 80, the inside of the pressurization container 110 is subjected to predetermined pressurization conditions higher than atmospheric pressure conditions (for example, 1115 hpa to 2027 hpa (1.1 atm to 2 atm). )) Under pressure. In this case, the restraining member 40 disposed in the pressurized container 110 is compressed, and the thickness of the restraining member 40 becomes thinner than the gap 81. Thereby, the restraint member 40 can be inserted from the insertion hole 65 of the case side face 62, and the restraint member 40 can be arrange | positioned in the clearance gap 81, as shown to FIG. 4 (B). 4B schematically shows the case 60 with the case side face 62 broken and the load adjusting screw 64 omitted for convenience of illustration. However, in order to indicate the insertion position of the restraining member 40 from the case side surface 62, the insertion hole 65 provided in the case side surface 62 is indicated by a broken line frame. The insertion and removal of the restraining member 40 is performed by an insertion robot hand (not shown) for grasping the restraining member 40 and inserting the restraining member 40 into the gap 81 from the insertion hole 65.

  FIG. 5 is an explanatory view showing a method of restraining the laminated body 10 by the restraining member 40 arranged in the unconstrained fastening body 80. 5A, similarly to FIG. 4A, for convenience of illustration, the non-restraining fastening body 80 on which the restraining member 40 has already been disposed is connected to the side surface of the front side of the case 60 and the insulator 50 (FIG. 5A). 1 schematically corresponds to the front side surface in the Y direction. FIG. 5B schematically shows the case side surface 62 of the case 60 with the load adjustment screw 64 omitted for convenience of illustration, as in FIG. 4B.

  As described with reference to FIG. 4, after the restraint member 40 is disposed in the gap 81, when the pressurized state of the pressurized container 110 is stopped and returned to the normal pressure state under the atmospheric pressure condition, the compressed restraint member 40 is Inflate. As described above, since the thickness of the restraining member 40 in the normal pressure state is set to be equal to or larger than the gap 81, the gap 81 is formed by the restraining member 40 as shown in FIGS. 5 (A) and 5 (B). Buried. Thereby, the laminate 10 is restrained by the restraining function of the restraining member 40 to suppress the movement of each unit cell, the shock and vibration are restrained by the buffering function, and the fuel cell 100 (impact resistance and vibration resistance is ensured). FIG. 1) can be obtained.

  Here, conventionally, the restraint member is assembled by placing the restraint member on the laminate before the laminate is accommodated in the case and fastening the laminate to the case, and crushing the restraint member on the inner surface of the case. This was done by accommodating and fastening the laminate. For this reason, there has been a problem that a member included in the laminate, for example, a member (MEA, separator) constituting the unit cell is deformed by the pressing force applied to the restraining member from the inner surface of the case. In addition, when replacing the restraining member, there is a problem that it is required to release the assembly of the case. In addition, as described in the problem, there is a problem that when the fuel cell is in a low temperature state, the restraining ability is reduced and the movement of each unit cell cannot be suppressed.

  However, in the case of the above-described embodiment, the case 60 is fastened to the first end plate 20A and the stacked body 10 sandwiched between the two end plates 20A and 20B is accommodated in the case 60, and then in a pressurized state. The constraining member 40 compressed in the above is inserted from the outside of the case 60 and disposed on the laminate 10. Then, the pressurized state is returned to the normal pressure state, and the restraining member 40 is expanded, so that the gap 81 between the laminated body 10 and the inner surface of the case 60 (specifically, the inner surface of the insulator 50) is formed by the restraining member 40. It is buried and the restraint of the laminated body 10 is realized. For this reason, it can suppress that the member contained in a laminated body, the member which comprises the unit cell 11, etc. deform | transform by the pressing force added to a restraint member when accommodating a laminated body in a case as mentioned above. In addition, the stack can be restrained regardless of the temperature environment, the movement of a plurality of single cells included in the stack can be suppressed, and the impact resistance and vibration resistance of the fuel cell can be improved. it can.

  Further, when replacing the restraint member 40, the restraint member 40 can be compressed and easily removed from the insertion hole 65 if the fuel cell 100 is placed in the pressurized container 110 and brought into a pressurized state. Therefore, as described above, the restraining member 40 can be easily replaced without releasing the case assembly.

B. Variations:
In the said embodiment, although the case where the four restraint members 40 were provided so that the corner | angular part of the laminated body 10 might be covered was shown as an example, it is not limited to this. For example, it is good also as a structure by which the constraining member was each provided in four side surfaces along the lamination direction of the laminated body 10. FIG. Moreover, it is good also as a structure by which the constraining member was each provided in the two opposing side surfaces of the laminated body 10. FIG. Moreover, it is good also as a structure by which the constraining member was provided in any one side surface of the laminated body 10. FIG.

  The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Laminated body 11 ... Single cell 12 ... Current collecting plate 13 ... Insulating plate 20A, 20B ... End plate 21 ... Flange 30 ... Pressure plate 40 ... Restraining member 50 ... Insulator 60 ... Case 61 ... Opening 62 ... Case side surface 63 ... Screw hole 64 ... Load adjusting screw 65 ... Insertion hole 66 ... Insertion cover 67 ... Through hole 68 ... Ventilation cover 69 ... Flange 70 ... Bolt 80 ... Unrestrained fastening body 81 ... Gap 92 ... Support part 94 ... Pressure shaft 100 ... Fuel cell 110 ... Pressurized container

Claims (1)

A fuel cell in which a laminate including a plurality of unit cells stacked is housed in a case,
A restraining member disposed between a side surface along the stacking direction of the laminate and an inner surface of the case;
The thickness of the restraining member in a state not accommodated in the case is less than a gap between the side surface of the laminate and the inner surface of the case under a predetermined pressurizing condition higher than an atmospheric pressure condition. Yes, and above the gap under the atmospheric pressure condition,
The fuel cell characterized by the above-mentioned.

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