JP2008140561A - Fuel cell and fuel cell manufacturing method - Google Patents

Abstract

Provided is a fuel cell that includes a cell stack in which a plurality of hollow cells are connected in parallel, can efficiently extract current from each hollow cell, and can improve the power generation efficiency of the fuel cell.
A pair of electrodes provided on an inner surface and an outer surface of a hollow electrolyte membrane, an internal current collector and an external current collector connected to the pair of electrodes, respectively, and at least one end thereof is open. A fuel cell comprising a cell stack in which two or more hollow cells 6 are connected in parallel, wherein the two or more hollow cells are bundled and bound by at least one conductive wire as an external current collector To form a binding unit 8, and at least one of the hollow cells constituting the binding unit is deformed from the original first shape to the second shape when a pressing force is applied from the outside, and A fuel cell, which is a resilient hollow cell having elasticity that generates a restoring force to return to the first shape, and retains the second shape by the tightening force of the conductive wire.
[Selection] Figure 8

Description

  The present invention relates to a fuel cell including a hollow cell having a hollow electrolyte membrane and a method for manufacturing the fuel cell.

  A fuel cell directly converts chemical energy into electrical energy by supplying fuel and an oxidant to two electrically connected electrodes and causing the fuel to be oxidized electrochemically. Unlike thermal power generation, fuel cells are not subject to the Carnot cycle and thus exhibit high energy conversion efficiency. Solid polymer electrolyte fuel cells using a solid polymer electrolyte as an electrolyte have advantages such as easy miniaturization and operation at a low temperature. Has been.

In the solid polymer electrolyte fuel cell, when hydrogen is supplied as a fuel, the reaction of the formula (1) proceeds at the anode.
H ₂ → 2H ⁺ + 2e ⁻ (1)
The electrons generated by the equation (1) reach the cathode after working with an external load via an external circuit. Then, the proton generated in the formula (1) moves by electroosmosis from the anode side to the cathode side in the solid polymer electrolyte membrane in a state of being hydrated with water.

When air (oxygen) is supplied as the oxidant, the reaction of the formula (2) proceeds at the cathode.
2H ⁺ + (1/2) O ₂ + 2e ⁻ → H ₂ O (2)
The water produced at the cathode mainly passes through the gas diffusion layer and is discharged to the outside.
As described above, the fuel cell is a clean power generation device that has no emissions other than water.

Conventionally, as a solid polymer electrolyte fuel cell, a catalyst layer serving as an anode and a cathode is provided on one surface of a planar solid polymer electrolyte membrane, and the obtained planar membrane / electrode assembly is provided. A flat unit cell has been developed in which gas diffusion layers are further provided on both sides of the substrate and sandwiched between planar separators. A plurality of such flat single cells are stacked and used as a fuel cell stack.
In order to improve the output density of the solid polymer electrolyte fuel cell, a proton conductive polymer membrane having a very thin film thickness is used as the solid polymer electrolyte membrane. This film thickness is already 100 μm or less, and even if a thinner electrolyte membrane is used to further improve the power density, the thickness of the single cell cannot be dramatically reduced from the present one. Similarly, the catalyst layer, the gas diffusion layer, the separator, and the like have been made thinner, but there is a limit to improving the output density per unit volume even by making all these members thinner. Therefore, it is expected that it will not be possible to meet the demand for miniaturization in the future.

Moreover, the sheet-like carbon material excellent in corrosivity is normally used for the said separator. In the separator, the carbon material itself is expensive, and a gas channel groove for uniformly distributing the fuel gas and the oxidant gas over the entire surface of the planar membrane / electrode assembly is formed by micromachining. Therefore, it has become very expensive. As a result, the manufacturing cost of the fuel cell was pushed up.
In addition to the above problems, for flat single cells, the periphery of single cells stacked in multiple layers should be reliably sealed so that fuel gas and oxidant gas do not leak from the gas flow path. However, there are many problems such as technical difficulties, and power generation efficiency may decrease due to deflection or deformation of the planar membrane / electrode assembly.

In recent years, a solid polymer electrolyte fuel cell has been developed in which a hollow cell in which an electrode is provided on each of an inner surface side and an outer surface side of a hollow electrolyte membrane is used as a basic power generation unit (for example, Patent Document 1). .
Since the fuel cell having such a hollow cell has a gas flow path in the hollow, a member corresponding to a separator used in a flat type is not necessary. Since different types of gas are supplied to the inner surface and the outer surface for power generation, it is not necessary to form a gas flow path. Therefore, cost reduction is expected in the manufacture. Further, since the cell has a three-dimensional shape, the specific surface area with respect to the volume can be increased as compared with the flat single cell, and the power generation output density per volume can be expected to be improved.

In a fuel cell having hollow cells, usually, a plurality of hollow cells are connected in parallel in order to obtain a large voltage. In order to obtain a large current, a plurality of hollow cell stacks in which hollow cells are connected in parallel are further connected in series.
The hollow cell has current collectors (internal current collector and external current collector) connected to electrodes provided on the inner surface and the outer surface of the hollow electrolyte membrane, and the current of each cell is taken out therefrom. When a plurality of hollow cells are connected in parallel, the current of the inner surface side electrode and the current of the outer surface side electrode of each cell are collected.
For example, Patent Document 1 discloses a fuel cell in which a plurality of hollow cells are wound around a common rod-shaped current collector by a wire-shaped wrapping element (see FIG. 2 of Patent Document 1). .

US2004 / 0175605 gazette

In order to improve the output of the entire fuel cell, it is necessary to reduce current collection loss at the connection portion between the electrode and the current collection material in the current collection path of each hollow cell. For this purpose, the contact pressure at the connection portion between the hollow cell and the current collector is important.
However, in a conventional fuel cell including a hollow cell, it has been difficult to maintain a contact pressure between an electrode and a current collector, particularly, an outer surface side electrode and an external current collector for a long period of time. One of the causes is that the polymer electrolyte contained in the hollow cell and the polymer electrolyte contained in the electrode deteriorate due to the use of the fuel cell for a long period of time, and the outer diameter of the hollow cell is changed over time. Change.

  It is known that the polymer electrolyte membrane and the polymer electrolyte contained in the electrode repeatedly swell and shrink due to changes in the moisture content in the cell in accordance with the operating conditions and operating conditions of the fuel cell. . Due to such repeated swelling and shrinkage, the polymer electrolyte membrane is thinned and the electrode is thinned, the thickness of the hollow cell is reduced, and the outer diameter of the hollow cell is changed. As a result, the contact between the electrode provided on the outer surface side of the hollow cell and the external current collector is lowered, and the contact pressure is lowered.

Specifically, in the fuel cell as disclosed above in FIG. 2 of Patent Document 1, the hollow cell is disposed around the rod-shaped current collector as an external current collector due to the shrinkage of the outer diameter of the hollow cell. There is a risk that the fixed wire may loosen over time. As a result, the contact pressure between the outer surface side electrode of the hollow cell and the rod-shaped current collector is lowered, and the current collection efficiency is lowered.
Further, as shown in FIG. 10 (10 -A), when an electrically conductive wire 16 is wound around the outer periphery of the hollow cell 17 as an external current collector, the wire 16 is deformed by contraction of the outer diameter of the hollow cell 17. Looseness (see FIG. 10 (10-B)), the contact pressure between the outer surface side electrode (outer surface) of the hollow cell 17 and the wire 16 that is an external current collector decreases.

  Conventional fuel cells have a fixed-size structure and are not equipped with a mechanism for correcting the decrease in contact pressure between the current collector and the outer electrode due to the shape change of the hollow cell as described above. Thus, it has been impossible to suppress a decrease in current collection efficiency over time accompanying a change in the shape of the hollow cell as described above.

  The present invention has been accomplished in view of the above circumstances, and in a fuel cell having a cell stack in which a plurality of hollow cells are connected in parallel, an electric current is efficiently extracted from each hollow cell and the power generation efficiency of the fuel cell is increased. For the purpose.

  The first fuel cell of the present invention has a hollow electrolyte membrane, a pair of electrodes provided on the inner surface and the outer surface of the hollow electrolyte membrane, and an internal current collector and an external current collector connected to the pair of electrodes, respectively. And a fuel cell comprising a cell stack in which two or more hollow cells open at least at one end are connected in parallel, wherein the two or more hollow cells are bundled, Bundled by at least one conductive wire that is a current collector to form a bundling unit, and when at least one of the hollow cells constituting the bundling unit is subjected to a pressing force from the outside, the original first A resilient hollow cell having elasticity that produces a restoring force that deforms from a shape to a second shape and returns to the first shape, and the resilient hollow cell within the binding unit is electrically conductive. For tightening power of wire rod It holds the second shape I is characterized in.

  The first fuel cell according to the present invention is configured to bind the binding unit by the restoring force of the recoverable hollow cell as described above, and to bind the binding unit with the conductive wire functioning as an external current collector of the hollow cell. The clamping force can be maintained over a long period. That is, according to the first fuel cell of the present invention, it is possible to suppress a decrease in the tightening force of the binding unit due to a reduction in the diameter of the hollow cell due to a decrease in the thickness of the electrolyte membrane or an elongation of the conductive wire. It is possible. Thus, in the fuel cell of the present invention, the contact pressure between the external current collector and the electrode of the hollow cell is maintained over a long period of time, so the current collection efficiency from the hollow cell is high and excellent power generation performance is exhibited. It is possible to provide a fuel cell.

  As the first and second shapes of the recoverable hollow cell, for example, the second shape is a substantially straight bar shape, and the first shape is a shape in which the substantially straight bar shape is curved in the radial direction. Is mentioned.

  The bundling unit is a hollow cell constituting the bundling unit, and the shape of the substantially straight bar shape that defines the second shape of the restorable hollow cell by placing the restorable hollow cell along the surface thereof. At least one hollow cell may be included. In this case, the recoverable hollow cell may be deformed into a second shape along the shape of the substantially straight rod of the shape-defining hollow cell. it can.

  In order to maximize the effect obtained by the restoring force of the restorative hollow cell, one tenth or more of the two or more hollow cells constituting one binding unit are the restorative hollow cell. Preferably there is.

  The binding form in the binding unit by the conductive wire is not particularly limited. For example, the two or more hollow cells are bound by winding the conductive wire around the binding unit. Examples thereof include a form and a form in which the two or more hollow cells are bound together by a net-like member braided with the conductive wire.

  In order to maintain the tightening force by the conductive wire, the bundling unit usually fixes at least both axial ends of the bundling unit together with the conductive wire to a support plate.

  The second fuel cell of the present invention has a hollow electrolyte membrane, a pair of electrodes provided on the inner and outer surfaces of the hollow electrolyte membrane, and an internal current collector and an external current collector connected to the pair of electrodes, respectively. And a fuel cell comprising a cell stack in which two or more hollow cells open at least at one end are connected in parallel, wherein at least one of the hollow cells is at least one rod-shaped member. Are bundled together and bound by at least one wire to form a binding unit, and at least one of the rod-shaped member and the wire is the external current collector, and the hollow cell and the rod-shaped member constituting the binding unit When at least one selected from the members is subjected to a pressing force from the outside, elasticity that generates a restoring force that deforms from the original first shape to the second shape and returns to the first shape. It is a recoverable hollow cell or a recoverable rod-shaped member, and the recoverable hollow cell and the recoverable rod-shaped member in the binding unit hold the second shape by the tightening force of the wire. It is what.

  The second fuel cell according to the present invention maintains the fastening force of the binding unit by the wire material that binds the binding unit over a long period of time by the restoring force of the recoverable hollow cell and / or the recoverable rod-shaped member. can do. That is, according to the second fuel cell of the present invention, the external cell is reduced by reducing the fastening force of the binding unit due to the reduction in the diameter of the hollow cell due to the reduction in the thickness of the electrolyte membrane or the extension of the conductive wire. It is possible to suppress a decrease in the contact pressure between the rod-shaped member and / or wire that is the current collector and the hollow cell. Thus, in the fuel cell of the present invention, the contact pressure between the external current collector and the electrode of the hollow cell is maintained over a long period of time, so the current collection efficiency from the hollow cell is high and excellent power generation performance is exhibited. It is possible to provide a fuel cell.

In the fuel cell of the present invention, for example, the rod-shaped member may have a hollow shape and function as a cooling pipe through which a cooling medium flows.
As a specific embodiment of the second fuel cell, for example, at least one of the hollow cells constituting the binding unit is the recoverable hollow cell, and the rod-shaped member has the recoverable property. A shape-defining rod-shaped member that defines a second shape of the restorable hollow cell by bringing the hollow cell along the surface thereof, and the resilience hollow-type cell along the shape of the shape-defining rod-shaped member The form which is deform | transformed into the 2nd shape is mentioned.
At this time, as the first shape and the second shape of the recoverable hollow cell, the second shape is a substantially straight bar shape, and the first shape is a shape in which the substantially straight bar shape is curved in the radial direction. There are some cases.
Furthermore, the shape-defining rod-like member has higher rigidity than the restorable hollow cell and has a substantially straight rod-like shape, and with the restorable hollow cell while holding the substantially straight rod-like shape. The form bundled with the said wire is mentioned. At this time, the bundling unit may have a configuration in which two or more hollow cells are arranged so as to surround the outer periphery of the shape-defining rod-shaped member.

  The binding form in the binding unit by the conductive wire is not particularly limited. For example, the hollow cell and the rod-shaped member may be bound by winding the wire around the outer periphery of the binding unit. And the said hollow cell and the said rod-shaped member may be bound by the net-like member which braided the said wire.

  In order to maintain the tightening force by the conductive wire, usually, at least both ends of the binding unit in the axial direction are fixed to the support plate together with the wire.

  The first fuel cell manufacturing method of the present invention includes a hollow electrolyte membrane, a pair of electrodes provided on the inner surface and the outer surface of the hollow electrolyte membrane, and an internal current collector and an external current collector connected to the pair of electrodes, respectively. And a manufacturing method of a fuel cell comprising a cell stack in which two or more hollow cells having at least one end opened are connected in parallel, and a pressing force is applied from the outside. Sometimes, two or more hollow cells are prepared, including a resilient hollow cell having elasticity that deforms from the original first shape to the second shape and generates a restoring force to return to the first shape. Two or more hollow cells including the restorable hollow cell are bundled and tightened so that the restorative hollow cell can maintain the second shape by at least one conductive wire as the external current collector. It is characterized by binding to form a binding unit. It is an.

As the first and second shapes of the recoverable hollow cell, for example, the second shape is a substantially straight bar shape, and the first shape is a shape in which the substantially straight bar shape is curved in the radial direction. Is mentioned.
As a specific embodiment, as a hollow cell constituting the binding unit, a substantially straight bar shape that defines the second shape of the recoverable hollow cell by placing the recoverable hollow cell along the surface thereof The shape-defining hollow cell is prepared at least, and the restorable hollow cell is deformed into the second shape along the substantially straight rod-like shape of the shape-defining hollow cell.
In order to maximize the effect obtained by the restoring force of the restorative hollow cell, it is preferable that one tenth or more of the hollow cells constituting one binding unit are composed of the restorative hollow cell. .

As a binding form of the binding unit by the conductive wire, for example, the two or more hollow cells may be bound by winding the conductive wire around an outer periphery of the binding unit, The two or more hollow cells may be bound by a net-like member woven with a conductive wire.
In order to maintain the tightening force by the conductive wire, it usually includes a step of fixing the binding unit to the support plate together with the conductive wire at least at both axial ends of the binding unit.

  The second fuel cell manufacturing method of the present invention includes a hollow electrolyte membrane, a pair of electrodes provided on the inner surface and the outer surface of the hollow electrolyte membrane, and an internal current collector and an external current collector connected to the pair of electrodes, respectively. And a method of manufacturing a fuel cell comprising a cell stack in which two or more hollow cells open at least at one end thereof are connected in parallel, comprising at least one hollow cell, at least One rod-shaped member and at least one wire are prepared, and at least one of the rod-shaped member and the wire is selected from a conductive material to be an external current collector, and the hollow cell and the wire At least one of the rod-shaped members has elasticity that generates a restoring force that transforms from the original first shape to the second shape and returns to the first shape when a pressing force is applied from the outside. Have resilience An empty cell or a restoring rod-shaped member is selected, and at least one hollow cell and at least one rod-shaped member including the restoring hollow cell or the restoring rod-shaped member are bundled, and the restoring property is obtained by at least one wire. The hollow cell and the restorable rod-shaped member are fastened and bound so that the second shape can be maintained, thereby forming a binding unit.

The rod-shaped member may have a hollow shape and function as a cooling pipe through which a cooling medium flows.
As a specific manufacturing method, the restorable hollow cell is prepared as at least one hollow cell constituting the binding unit, and the restorative hollow cell is provided on the surface as the rod-shaped member. Preparing a shape-defining rod-shaped member that defines the second shape of the restorable hollow cell by aligning, and forming the restorable hollow cell into the second shape along the shape of the shape-defining rod-shaped member There is a method of deformation.

  As the first and second shapes of the recoverable hollow cell, for example, the second shape of the recoverable hollow cell is a substantially straight bar shape, and the first shape is a substantially straight bar shape in the radial direction. An example is a curved shape. At this time, as the shape-defining rod-shaped member, one having higher rigidity than the restorable hollow cell and having a substantially straight rod-like shape is used, and the shape-defining rod-shaped member is used as the substantially straight rod-shaped member. In the state which hold | maintained, it can bind by the said wire with the said recoverable hollow type cell. Further, the hollow cells may be arranged and bound so as to surround the outer periphery of the shape defining rod-shaped member.

The method of binding the binding unit with the wire is not particularly limited, for example, the method may be a method of binding the hollow cell and the rod-like member by winding the wire around the binding unit, A method of binding the hollow cell and the rod-like member by a net-like member knitted with a wire may be used.
In order to maintain the tightening force by the conductive wire, it usually includes a step of fixing the binding unit to the support plate together with the wire at least at both axial ends of the binding unit.

  According to the present invention, the contact pressure between the hollow cell and the current collector can be maintained over a long period of time, and the contact resistance between the current collector and the hollow cell can be reduced. Therefore, the fuel cell of the present invention can suppress a decrease in output caused by a decrease in contact pressure between the hollow cell and the current collector even when used for a long period of time, and exhibits stable power generation performance.

  The fuel cell of the present invention has a hollow electrolyte membrane, a pair of electrodes provided on the inner surface and the outer surface of the hollow electrolyte membrane, an internal current collector and an external current collector connected to the pair of electrodes, respectively The basic structure is a cell stack in which two or more hollow cells having at least one end opened are connected in parallel. The first fuel cell of the present invention includes the two or more hollow cells. The cells are bundled and bound by at least one conductive wire that is the external current collector to form a binding unit, and at least one of the hollow cells constituting the binding unit is loaded with a pressing force from the outside. Sometimes a resilient hollow cell that has elasticity to produce a restoring force that deforms from the original first shape into the second shape and returns to the first shape, and the resilient hollow cell is within the binding unit. Type cell And it is characterized in that it holds the second shape by the clamping force of sexual wire.

  In the second fuel cell of the present invention, at least one of the hollow cells is bundled together with at least one rod-shaped member, and is bound by at least one wire to form a bundling unit. The rod-shaped member and the wire At least one of the external current collector, and at least one selected from the hollow cell and the rod-shaped member constituting the binding unit is the original first shape when a pressing force is applied from the outside. A reversible hollow cell or a resilient rod-like member having elasticity that produces a restoring force that deforms from the first shape to the second shape and returns to the first shape. The recoverable rod-like member is characterized in that the second shape is held by the tightening force of the wire.

  In the fuel cell of the present invention, in the binding unit including the hollow cell or the hollow cell and the rod-shaped member, the hollow cell and / or the rod-shaped member constituting the binding unit is formed by the tightening force of the wire rod that binds the binding unit. At least one of them is deformed and a restoring force is generated. The restoring force generated at this time acts in a direction to return to the original shape from the deformed state due to the tightening force of the wire, that is, pushes back the tightening force by the wire.

  In this way, by binding the binding unit including the hollow cell in a state where a restoring force is generated in the constituent member, a large fastening force to the binding unit by the wire is maintained for a long period of time. Therefore, for example, even when the diameter of the hollow cell is reduced, or when the wire that binds the binding unit is extended, the dimensional change of the hollow cell or the conductive wire is allowed, and the binding unit to the binding unit by the wire is allowed. Tightening force can be maintained. Therefore, in the fuel cell according to the present invention, when the hollow cells constituting the bundling unit include a rod-shaped member in the bundling unit, the rod-shaped member and the hollow cell, the wire material for bundling the bundling unit, and the bundling unit are further included. The hollow cell and the rod-shaped member which constitute are always in pressure contact, and a high contact pressure is maintained.

  In other words, according to the present invention, when a conductive material is used as the rod-shaped member and / or wire, and it functions as a current collector, the hollow cells constituting the binding unit and the current of the hollow cells are collected. Since the current collector can be brought into contact with a rod-like member and / or wire that is always kept at a high contact pressure, the current collection efficiency is high and the current collection loss between the hollow cell and the current collection material is reduced. be able to.

As an element that determines the current collection efficiency between the electrode and the current collector that directly contacts the electrode and collects current, the area and contact pressure of these connection parts can be mentioned, but the contact pressure is more Significantly affects current collection efficiency. That is, even when the contact area is large, the contact pressure is generally low, and when the contact area is small, the contact pressure is kept high. The current collection efficiency is higher. Therefore, a fuel cell excellent in current collection efficiency can be obtained by maintaining a high contact pressure in at least a part of the connection portion between the electrode and the current collector.
The present invention has been accomplished on the basis of such knowledge, and the restoring force generated when the original first shape is deformed to the second shape by a load due to an external pressing force is applied to the current collector and the electrode. As a means for maintaining a high contact pressure, it was possible to increase the current collection efficiency. Furthermore, by maintaining the contact pressure between the current collector and the electrode for a long period of time, it is possible to provide a fuel cell that suppresses a decrease in current collection efficiency and exhibits stable power generation performance over a long period of time.

  Hereinafter, an embodiment of the fuel cell of the present invention will be described with reference to FIGS. In the following embodiment, the description will focus on a polymer electrolyte fuel cell using hydrogen gas as the fuel and air (oxygen) as the oxidant, but the present invention is not limited to the following embodiment. Absent. 1 to 9 may omit a part of the structure for the sake of convenience.

[Hollow cell]
FIG. 1 is a schematic view showing an embodiment of hollow cells that are connected in parallel to form a cell stack in the fuel cell of the present invention, and FIG. 2 is a cross-sectional view of the hollow cell of FIG. 1 and 2, a hollow cell 6 includes a tube-shaped solid polymer electrolyte membrane (perfluorocarbon sulfonic acid resin) 1 and an anode (an inner surface side electrode, which is provided on the inner surface side of the solid polymer electrolyte membrane 1). In the embodiment, it has a fuel electrode) 2 and a cathode (outer surface side electrode, which is an air electrode in this embodiment) 3 provided on the outer surface side. Further, a columnar current collector is disposed on the surface of the anode 2 as an anode-side current collector (in this embodiment, an internal current collector) 4, and a cathode current collector (in the present embodiment, an external current collector) is disposed on the surface of the cathode 3. ) 5, a linear current collector made of a metal wire (conductive wire) is arranged.
On the hollow inner surface of the hollow cell having such a structure (substantially, the portion exposed to the inner surface side gas flow path formed by the groove 4a provided on the outer surface of the anode current collector 4), hydrogen gas on the outer surface By circulating air, fuel or an oxidant is supplied to the anode and cathode to generate electricity.

The hollow cell 6 shown in FIG. 1 has hollow portions open at both ends, and the fuel gas flows from one end into the hollow and flows out from the other end. In the hollow cell 6, if the reaction gas can be sufficiently supplied to the inner surface side of the hollow electrolyte membrane, only one end of the hollow portion may be opened and the other end may be sealed.
In particular, as in the present embodiment, when providing a fuel electrode using hydrogen as a fuel as the inner surface side electrode, hydrogen gas containing almost no non-reactive component can be supplied into the hollow of the hollow cell as a fuel gas, In addition, since the diffusibility of hydrogen molecules is high, the reaction gas supplied into the hollow can be consumed, so that the reaction gas can be sufficiently supplied even in the hollow portion with one end sealed. . Examples of the method of sealing one end of the hollow cell include a method of injecting resin or the like into the hollow one end, but is not particularly limited.

  In FIG. 1, the hollow cell 6 has a tubular electrolyte membrane, but the hollow electrolyte membrane in the present invention is not limited to a tubular shape, has a hollow portion, and fuel and an oxidant flow into the hollow portion. By doing so, it is only necessary that the reaction component necessary for the electrochemical reaction can be supplied to the electrode provided in the hollow interior.

The inner diameter, outer diameter, length and the like of the tubular solid polymer electrolyte membrane 1 are not particularly limited, but the outer diameter of the tubular electrolyte membrane is preferably 0.01 to 10 mm, 0.1 More preferably, it is-1 mm, and it is especially preferable that it is 0.1-0.5 mm. At present, it is difficult to manufacture a tubular electrolyte membrane having an outer diameter of less than 0.01 mm due to technical problems. On the other hand, when the outer diameter exceeds 10 mm, the surface area relative to the occupied volume is not so large. The output per unit volume of the obtained hollow cell may not be sufficiently obtained.
The electrolyte membrane is preferably thin from the viewpoint of improving proton conductivity. However, if the electrolyte membrane is too thin, the function of isolating gas is reduced, and the amount of aprotic hydrogen permeation is increased. However, compared to conventional fuel cells in which flat single cells for fuel cells are stacked, a fuel cell manufactured by collecting a large number of cells having a hollow shape can take a large electrode area, so a slightly thicker membrane is formed. Even when used, a sufficient output can be obtained. From this viewpoint, the thickness of the electrolyte membrane is 10 to 100 μm, more preferably 50 to 60 μm, and still more preferably 50 to 55 μm.
Moreover, from the preferable range of said outer diameter and film thickness, the preferable range of an internal diameter is 0.01-10 mm, More preferably, it is 0.1-1 mm, More preferably, it is 0.1-0.5 mm. is there.

  Since the fuel cell of the present invention has a hollow cell, the electrode area per unit volume can be made larger than that of a fuel cell having a flat cell. Therefore, as the solid polymer electrolyte membrane, perfluorocarbon sulfonic acid is used. Even when an electrolyte membrane that does not have a proton conductivity as high as that of a resin membrane is used, a fuel cell having a high output density per unit volume can be obtained. As the solid polymer electrolyte membrane, perfluorocarbon sulfonic acid resin and materials used for the electrolyte membrane of solid polymer fuel cells can be used. For example, fluorine other than perfluorocarbon sulfonic acid resin can be used. One kind of proton exchange groups such as at least sulfonic acid groups, phosphonic acid groups, and phosphoric acid groups, based on hydrocarbons such as polyolefins such as polystyrene ion exchange resins and polystyrene cation exchange membranes having sulfonic acid groups A complex of a basic polymer and a strong acid, which is disclosed in Japanese Patent Application Laid-Open No. 11-503262, etc., in which a basic polymer such as polybenzimidazole, polypyrimidine, and polybenzoxazole is doped with a strong acid And polymer electrolytes such as solid polymer electrolytes. A solid polymer electrolyte membrane using such an electrolyte should be reinforced with a perfluorocarbon polymer in the form of a fibril, a fabric, a non-fabric, or a porous sheet, or the membrane surface can be coated with an inorganic oxide or metal. It can also be reinforced. In addition, examples of the perfluorocarbon sulfonic acid resin membrane include commercially available products such as Nafion manufactured by DuPont and Flemion manufactured by Asahi Glass.

In the present embodiment, a perfluorocarbon sulfonic acid resin membrane, which is a kind of proton conductive membrane and one of solid polymer electrolyte membranes, is described as an electrolyte membrane, but it is used in the fuel cell of the present invention. The electrolyte membrane to be used is not particularly limited, and may be proton-conductive or other ion-conductive such as hydroxide ion or oxide ion (O ²⁻ ). The proton conductive electrolyte membrane is not limited to the solid polymer electrolyte membrane as described above, but a porous electrolyte plate impregnated with an aqueous phosphoric acid solution, a proton conductor made of porous glass, or a hydrogel Phosphated phosphate glass, organic-inorganic hybrid proton conductive membrane having proton conductive functional groups introduced into the surface and pores of nanoporous glass, inorganic metal fiber reinforced electrolyte polymer, etc. can be used. .
Depending on the configuration of the fuel cell, for example, when the present invention is applied to a solid oxide fuel cell or to a solid polymer fuel cell using hydroxide ions as charge carriers, oxygen ions or It may be a solid electrolyte membrane that conducts ions serving as other charge carriers such as hydroxide ions.

  Each of the electrodes 2 and 3 provided on the inner and outer surfaces of the electrolyte membrane 1 can be formed using an electrode material used in a polymer electrolyte fuel cell. The configuration of each electrode is not particularly limited, and in addition to the configuration in which the catalyst layer and the gas diffusion layer are laminated in order from the electrolyte membrane side, the configuration consisting of only the catalyst layer and the functional layer in addition to the catalyst layer and the gas diffusion layer are provided. Configuration.

  The catalyst layer includes catalyst particles, and may further include a proton conductive material for increasing the utilization efficiency of the catalyst particles. As the proton conductive material, those used as the material for the electrolyte membrane can be used. As the catalyst particles, catalyst particles in which a catalyst component is supported on a conductive material such as a carbon material such as carbonaceous particles or carbonaceous fibers are preferably used.

Since the fuel cell of the present invention has a hollow cell, the electrode area per unit volume can be made larger than that of a fuel cell having a flat cell. Therefore, a catalyst component that is not as catalytic as platinum is used. However, a fuel cell having a high output density per unit volume can be obtained.
The catalyst component is not particularly limited as long as it has a catalytic action for hydrogen oxidation reaction at the anode and oxygen reduction reaction at the cathode. For example, platinum (Pt), ruthenium (Ru), iridium (Ir) , Rhodium (Rh), palladium (Pd), osmium (Os), tungsten (W), lead (Pb), iron (Fe), chromium (Cr), cobalt (Co), nickel (Ni), manganese (Mn) , Vanadium (V), molybdenum (Mo), gallium (Ga), aluminum (Al) and other metals, or alloys thereof. Pt and an alloy made of Pt and another metal such as Ru are preferable.

As the gas diffusion layer, a porous conductive material mainly composed of a carbon material such as carbonaceous particles and / or carbonaceous fibers can be used. The sizes of the carbonaceous particles and the carbonaceous fibers may be appropriately selected in consideration of the dispersibility in the solution when the gas diffusion layer is produced, the drainage property of the obtained gas diffusion layer, and the like.
The gas diffusion layer is, for example, polytetrafluoroethylene, polyvinylidene fluoride (PVDF), polytetrafluoroethylene, perfluorocarbon alkoxyalkane, ethylene-tetrafluoroethylene polymer, or these from the point of improving the drainage of moisture such as generated water It is preferable to perform water-repellent processing by impregnating a mixture of the above or the like or forming a water-repellent layer using these substances.
In addition, the structure of each electrode provided in the inner surface and outer surface of a hollow electrolyte membrane, the material used for an electrode, etc. may be the same, and may differ.

The method of providing a pair of electrodes on the inner and outer surfaces of the tubular electrolyte membrane is not particularly limited. For example, first, a tubular electrolyte membrane is prepared. The method for preparing the tubular electrolyte membrane is not particularly limited, and a commercially available electrolyte membrane formed in a tube shape can also be used.
Then, a solution containing electrolyte and catalyst particles is applied and dried on the inner and outer surfaces of the tubular electrolyte membrane to form a catalyst layer, and carbonaceous particles and / or carbonaceous fibers are contained on the two catalyst layers. The method of apply | coating and drying a solution and forming a gas diffusion layer is mentioned. At this time, the catalyst layer and the gas diffusion layer are formed so that a hollow portion exists on the inner surface of the gas diffusion layer formed on the inner surface side of the electrolyte membrane.

Alternatively, first, a gas material containing a carbon material such as carbonaceous particles and / or carbonaceous fibers and formed into a tube shape (tubular carbonaceous material) is used as the gas diffusion layer of the inner surface side electrode (anode), and the gas diffusion is performed. Applying and drying a solution containing electrolyte and catalyst particles on the outer surface of the layer to form a catalyst layer of the inner surface side electrode to produce the inner surface side electrode, and then applying a solution containing the electrolyte to the outer surface of the catalyst layer. The electrode layer is dried to form a catalyst layer of the outer electrode (cathode) on the outer surface of the electrolyte membrane layer, and a solution containing a carbon material is applied to the outer surface of the catalyst layer and dried to dry the gas of the outer electrode. A method for forming a diffusion layer is also included.
The tubular carbonaceous material can be obtained, for example, by dispersing a carbon material such as carbonaceous particles and an epoxy and / or phenolic resin in a solvent to form a tubular shape, thermosetting, and firing.

In addition, the solvent used when forming the electrolyte membrane, the catalyst layer, and the gas diffusion layer may be appropriately selected according to the material to be dispersed and / or dissolved, and the coating method when forming each layer is also as follows. It can be appropriately selected from various methods such as spraying and screen printing.
The hollow cell used in the fuel cell of the present invention is not limited to the configuration exemplified above, and layers other than the catalyst layer and the gas diffusion layer may be provided for the purpose of enhancing the function of the hollow cell. In this embodiment, the anode is provided inside the hollow electrolyte membrane and the cathode is provided outside, but the cathode may be provided inside and the anode may be provided outside.

  The internal current collector 4 (in this embodiment, the anode current collector) 4 disposed on the inner surface side electrode surface is a columnar current collector having an outer diameter in contact with the inner peripheral surface of the hollow cell, A groove 4a extending in the axial direction (longitudinal direction) of the hollow cell is formed. A gap between the groove and the inner surface side electrode 2 becomes a hollow gas passage for supplying hydrogen gas. As the groove 4a, at least one groove extending in the axial direction (longitudinal direction) of the hollow cell is required, and grooves having various patterns or directions are formed on the outer peripheral surface of the hollow cell as necessary. The

  An external current collector (cathode-side current collector in this embodiment) 5 arranged on the outer surface side electrode surface is made of a conductive wire such as a metal wire, and is formed by bundling a plurality of hollow cells 6. It is wound around the outer periphery of the unit 8 (see FIG. 4) and is attached to the outer periphery of the cathode 3 which is the outer surface of each hollow cell 6. At this time, the conductive wire may be a braided mesh member. Further, in the present embodiment, the conductive wire as an external current collector is in contact with a plurality of hollow cells, and one external current collector is shared by all the hollow cells constituting the binding unit. However, in addition to the conductive wire that binds the binding units, for example, a conductive wire or a conductive rod-shaped member that collects current of individual or plural hollow cells may be used in combination.

  Examples of the metal used as the cathode side or anode side current collector include at least one metal selected from Al, Cu, Fe, Ni, Cr, Ta, Ti, Zr, Sm, In, and the like, Or their alloys such as stainless steel are preferred. Further, the surface thereof may be coated with Au, Pt, conductive resin or the like. Of these, stainless steel and titanium are preferred because of their excellent corrosion resistance. The thickness of the wire and the braid density, the thickness of the rod-shaped current collector, etc. are not particularly limited.

Here, the columnar internal current collector (anode-side current collector in this embodiment) 4 and the linear external current collector (in this embodiment, the cathode current collector) 5 have been mainly described. Is not particularly limited, and the shape thereof is arbitrary as long as it is made of an electrically conductive material. The current collector may be a columnar shape, a wire shape, a rod shape, a linear shape, or a cylindrical shape. For example, a material made of a sheet material such as a spring-like metal wire, a metal foil, a metal sheet, or a carbon sheet can be applied.
These current collectors are fixed on the electrodes with a conductive adhesive such as a carbon-based adhesive or an Ag paste as necessary.

  The hollow cell constituting the fuel cell of the present invention has a property of generating a restoring force by being deformed by an external pressing force, that is, a force to return to the original shape when deformed within an elastic deformation range. A restorative hollow cell having properties can be used.

The hollow cell having the structure as described above is deformed from the original first shape to the second shape and restored to the first shape when an external pressing force is applied. Since it has resilience having elasticity that generates force, it can be used as a resilience hollow cell.
However, as the restorable hollow cell, those given elasticity exhibiting stronger resilience are preferable from the viewpoint of current collection efficiency. Therefore, as a columnar current collector that is an internal current collector, for example, copper alloys such as beryllium copper, titanium copper, tungsten copper, phosphor bronze, metals used as spring materials such as titanium alloys, and strong aluminum alloys It is preferable to use a material capable of expressing a restoring force. Among these, aluminum alloys are preferably used from the viewpoints of conductivity and lightness.

<First fuel cell>
[Cell stack and fuel cell]
A first fuel cell according to the present invention includes a cell stack in which two or more hollow cells as described above are connected in parallel (of which at least one of the bundling units is a recoverable hollow cell). It is. Hereinafter, the cell stack in the first fuel cell will be described with reference to FIGS. In each figure, the number of hollow cells, gas flow paths, and the like may be omitted for convenience.
FIG. 3 is a diagram showing an example of a cell stack provided in a fuel cell to which the present invention is applied. FIG. 4 shows a binding unit provided in the cell stack of FIG.

In the cell stack 100 and the binding unit 8 shown in FIGS. 3 and 4, the hollow cell 6 has the structure shown in FIGS. 1 and 2. That is, the anode provided on the inner surface of the hollow electrolyte membrane, the cathode provided on the outer surface, the cathode side current collector (external current collector), and the anode side current collector (internal current collector) are arranged so as to contact each electrode. Installed and connected.
The plurality of hollow cells 6 are bundled so that their longitudinal directions are parallel to each other, and form a binding unit 8 that is bound by a conductive wire 7 that is attached to the outer periphery thereof (4-B, 4 in FIG. 4). -See C). At least one of the hollow cells 6 constituting the binding unit 8 is a recoverable hollow cell 6A, and the first shape (6a) to the second shape ( 6a ′) and is bound by the conductive wire 7 (see 4-A in FIG. 4). In addition, 4-C of FIG. 4 is sectional drawing of the broken-line part of 4-B.

  The recoverable hollow cell 6A has a first shape when released from an external force, but deforms to a second shape and returns to the first shape when an external pressing force is applied. It has elasticity to generate a restoring force to try. That is, when the restorable hollow cell is released from the external force due to the conductive wire, a gap is formed between it and the hollow cell constituting the binding unit, but in a state where the pressing force is applied by the conductive wire. When it is bound together with other hollow cells and deformed so that the gap between the other hollow cells is small, a restoring force is generated to return to the original shape.

Thus, by deforming the hollow cell constituting the binding unit by the tightening force of the conductive wire that binds the binding unit, the tightening of the conductive wire is pushed back to the deformed hollow cell. In addition, a restoring force in the outer diameter direction of the binding unit is generated. As a result, in the entire binding unit, a high contact pressure acts on a contact portion between the hollow cell constituting the binding unit and the conductive wire material binding the binding unit.
In addition, for example, in the conventional fuel cell, the contact pressure can be kept high even when the tightening force of the binding unit is reduced by the conductive wire. That is, in the fuel cell of the present invention, the contact pressure between the outer surface of the hollow cell, that is, the outer surface side electrode (cathode in the present embodiment) and the conductive wire as the current collector is always kept high. It is possible to maintain stable current collection efficiency over a period.

  As described above, in the fuel cell of the present invention, the contact pressure between the outer surface side electrode of the hollow cell and the external current collector that collects the current of the outer surface side electrode is always kept high. Therefore, the fuel cell of the present invention has a small current collection loss between the hollow cell and the current collector, and is excellent in current collection efficiency.

  In a bundling unit formed by bundling two or more hollow cells, the hollow cells are usually connected in parallel. Then, as shown in FIG. 3, two or more bundling units 8 composed of the hollow cells connected in parallel are provided in the cell stack 100 in parallel connection or series connection. One unit may be provided in the cell stack. In FIG. 3, each bundling unit 8 collects current by connecting the end of the conductive wire 7, which is an external current collector, to the external current collector connection portion 12, and is connected in parallel. In FIG. 3, the parallel connection of the internal current collectors of each binding unit is omitted.

  In the fuel cell of the present invention, the number of hollow cells constituting the bundling unit, the number of bundling units incorporated in the cell stack, and the case where two or more bundling units are incorporated, the connection configuration between the bundling units, and the incorporation into the fuel cell. In the case of incorporating two or more cell stacks, the connection between the cell stacks is not particularly limited, and may be appropriately selected so as to obtain a desired current and voltage. Further, the flow direction and supply method of each reaction gas are not particularly limited.

  In a bundling unit formed by bundling two or more hollow cells connected in parallel, a recoverable hollow cell deformed from the first shape to the second shape by the pressing force due to the bundling of conductive wires is restored. The pressing force is generated between the bundled hollow cells and between the conductive wires that bind the binding units and the hollow cells.

The first shape (the shape before deformation) and the second shape (the shape after deformation) of the restorative hollow cell that is deformed and generates restoring force as described above are not particularly limited. In general, from the viewpoint of the design of a fuel cell on which the cell stack is mounted, the second shape is preferably a substantially straight bar. Here, the term “substantially straight bar shape” means that the axial direction of the longitudinal direction and the surface shape thereof are substantially linear bar shapes, and the axial direction is constant and the surface is substantially flat.
The initial shape (first shape) before deformation that becomes a substantially straight bar shape in a state in which the binding unit is bound by the conductive wire includes a shape in which the substantially straight bar shape is curved in the radial direction. As a specific example, The thing shown in FIG. 5 is mentioned. The shape in which the substantially straight bar shape is curved in the radial direction is a shape in which the substantially straight bar shape partially or entirely draws an arc.

In the first fuel cell, at least one of the two or more hollow cells constituting the binding unit is the recoverable hollow cell, and the restoring force is not generated by the tightening force of the conductive wire. As long as the second shape deformed from the first shape is bound, the number and the arrangement in the binding unit are not particularly limited. For example, all the hollow cells constituting the binding unit are restored. And may be bound in a binding unit in a state where a restoring force is generated, that is, in a deformed state.
From the standpoint of ensuring the contact pressure between the conductive wire and the hollow cell, at least one-tenth or more of the two or more hollow cells constituting one binding unit is a recoverable hollow cell. It is preferable to do. All the hollow cells constituting the binding unit may be a recoverable hollow type.

A hollow cell that is bound in a state where no restoring force is generated, the deformable hollow cell is deformed so that the gap between the hollow cell and the restorative hollow cell is reduced. By functioning, it functions as a shape-defining hollow cell that defines the second shape, which is the deformed shape of the recoverable hollow cell. The shape-defining hollow cell may have rigidity that functions as a shape-defining hollow cell alone, or a plurality of shape-defining hollow cells that exhibit rigidity that functions as a shape-defining hollow cell.
As described above, when the shape of the restorable cell is deformed, that is, the second shape is a substantially straight bar shape, and the original shape, that is, the first shape is a shape in which the substantially straight bar shape is curved in the radial direction, As the shape defining hollow cell, a cell having a substantially straight bar shape is used.

The conductive wire that binds the binding unit in which a plurality of hollow cells are bundled functions as a current collector that collects the current of the hollow cells that constitute the binding unit. Those listed as materials for the current collector can be used. Among these, aluminum alloys are preferable from the viewpoint of conductivity and lightness.
In the present invention, the wire is not limited to the shape of the cross section, and for example, the cross section may be a wire having a small aspect ratio such as a circle, or a strip-shaped wire having a large cross section. Good.

The bundling method of the bundling unit using the conductive wire does not interfere with the supply of the reaction gas to the electrode provided on the outer surface of the hollow cell, and can collect current from the electrode and apply a clamping force to the hollow cell. If possible, there is no particular limitation.
Typical examples include a form in which a single conductive wire is spirally wound on the outer periphery of the binding unit (see FIG. 4), but there are other forms such as a braided wire shape, a twisted wire shape, and the like. Can be mentioned. Moreover, as shown in FIG. 6, the form which wound the net-like member which braided the electroconductive wire around the outer periphery of the binding unit in the state which gave the pressing force may be sufficient. One or a plurality of conductive wires for binding one binding unit may be used.

  The binding unit 8 bound by the conductive wire preferably has at least both ends in the axial direction of the binding unit fixed to the support plate 13 together with the conductive wire in order to maintain the state of binding by the conductive wire (FIG. 7). reference). Thus, by fixing the binding unit together with the conductive wire, the winding form of the conductive wire relative to the binding unit can be fixed, and the binding state of the binding unit by the conductive wire can be maintained. it can.

Here, the axial direction of the binding unit is the axial direction of the hollow cells constituting the binding unit, and usually coincides with the longitudinal direction of the hollow cells bound in the binding unit. Further, both ends in the axial direction of the binding unit refer to the vicinity of both ends in the axial direction, and the specific position and the like are not particularly limited. However, the support plate for fixing both ends of the binding unit is usually an outer surface side electrode. Functions as a partition wall that prevents mixing of the reaction gas supplied to the inner electrode and the reaction gas supplied to the inner surface side electrode (supplied into the hollow of the hollow cell), and is sandwiched between two support plates The open space forms a flow path for the reaction gas supplied to the outer surface side electrode. That is, the position of the support plate is determined in consideration of the effective surface area of the outer surface side electrode in addition to the support of the hollow cell and the holding state of the binding unit.
A method for fixing the hollow cell and the conductive wire in the support plate is not particularly limited. For example, in the state where the binding unit 8 is inserted into the through hole 14 of the support plate 13 as shown in FIG. A method of pouring the potting material 15 onto at least one of the surfaces of 13 and solidifying it is mentioned.

<Second fuel cell>
[Cell stack and fuel cell]
The second fuel cell of the present invention comprises a cell stack in which two or more hollow cells as described above are connected in parallel. Hereinafter, the cell stack according to the present invention will be described with reference to FIGS.
8 and 9 are each an embodiment of a binding unit provided in a cell stack of a fuel cell to which the present invention is applied.
In the second fuel cell, the bundling unit is a bundling of hollow cells and rod-shaped members, and the bundling units are bundled using a reversible hollow cell and / or a reversible rod-shaped member as a member showing a restoring force. The first fuel cell is greatly different in that at least one of the wire rod and the rod-shaped member constituting the binding unit functions as an external current collector. Here, the second fuel cell will be described focusing on differences from the first fuel cell.

  In the binding unit 8 shown in FIG. 8, the plurality of hollow cells 6 are arranged so as to surround the outer periphery of a bar-shaped member (bar-shaped current collector) 9 in a state in which the longitudinal direction thereof is parallel, together with the bar-shaped member 9, They are bound by a wire (conductive wire) 11 to form a binding unit 8 (see 8-B in FIG. 8). In the embodiment shown in FIG. 8, a part of the hollow cells 6 constituting the binding unit together with the rod-shaped current collector (rod-shaped member) 9 is a recoverable hollow cell, so that a restoring force is generated. It is bound by the wire 11 in a state of being deformed from the shape (6a) to the second shape (6a ′) (see 8-A in FIG. 8). In FIG. 8, 8-C is a cross-sectional view taken along a broken line portion of 8-B.

In the binding unit 8, a force in the outer diameter direction of the binding unit 8 that pushes back the tightening of the wire 11 is generated by the restoring force of the recoverable hollow cell 6 </ b> A that is bound in a deformed state by the tightening force of the wire 11. The contact pressure between the wire 11 and the hollow cell 6 is high. Along with this, the contact pressure between the hollow cell 6 and the rod-shaped member 9 which is an external current collector is also increased. That is, the contact pressure between the hollow cell 6 and the rod-shaped member 9 and the wire 11 that function as an external current collector of the hollow cell 6 is high.
In this way, by deforming at least one of the hollow cell and the bar-shaped member constituting the binding unit by the tightening force of the wire rod that binds the binding unit, the deformed hollow-type cell and / or the bar-shaped member Produces a restoring force in the outer diameter direction of the binding unit that pushes back the tightening of the wire rod. As a result, in the entire bundling unit, a high contact pressure is generated at the contact portion between the hollow cell constituting the bundling unit and the rod-like member and / or wire that is the external current collector, and as in the first fuel cell, A fuel cell excellent in electric efficiency can be obtained.

  In the embodiment shown in FIG. 8, one binding unit is composed of a plurality of hollow cells, but in the second fuel cell of the present invention, the number of hollow cells constituting the binding unit is particularly limited. There may be only one, or two or more.

In FIG. 8, a rod-shaped current collector is used as the rod-shaped member, and the rod-shaped current collector also functions as a cooling pipe for controlling the temperature of the hollow cell. Specifically, the rod-shaped current collector 9 has a hollow shape, and the temperature of the hollow cell can be adjusted by circulating a cooling medium (for example, water) in the hollow. The rod-shaped member may function as a current collector or a cooling pipe as in the present embodiment, or may function as a current collector (see FIG. 9) or a cooling pipe.
When the rod-shaped member functions as an external current collector, at least a part of the rod-shaped member is made of a conductive material, and when it functions as a cooling pipe, at least a portion of the rod-shaped member is made of a heat conductive material. In the case of a cooling pipe, typically, a cooling medium is circulated in the hollow pipe, but the case of the current collector is not limited to solid, and a hollow tubular member is used as the current collector for the purpose of weight reduction or the like. May be. In the embodiment shown in FIG. 9, a plurality of hollow cells 6 are disposed in contact with the outer peripheral surface of a solid rod-shaped member (external current collector) 9, and the current of each hollow cell 6 is a rod-shaped member ( Current is collected by an external current collector 9.

In the present embodiment, the rod-shaped member (bar-shaped current collector) is such that the recoverable hollow cell is deformed along its surface and functions as a shape defining member of the recoverable hollow cell. As a rod-shaped member, a restoring rod-shaped member (when a pressing force from the outside is applied, a deforming force is generated that deforms from the original first shape to the second shape and tries to return to the first shape. (Having elasticity) can also be used. Depending on the rigidity, thickness, number, etc. of the hollow cells that together form the binding unit, by binding the binding unit in the second shape obtained by deforming the recoverable rod-shaped member from the original first shape, It is possible to obtain the same effect as in the case of binding the binding unit in a state where the recoverable hollow cell is deformed. Usually, the cooling pipe and the current collector are often more rigid than the hollow cell, and often function as a rod-shaped member for defining the shape of the recoverable hollow cell or the recoverable rod-shaped member.
It has resilience and is bound in the binding unit while maintaining the deformed state from the original first shape to the second shape, among the recoverable hollow cell and the recoverable rod-shaped member. At least one may be used, and only the recoverable hollow cell may be used as in the present embodiment of FIGS. 8 and 9, or only the recoverable rod-shaped member may be used. Both rod-like members may be used.

  As a restoring rod-shaped member, what was formed using elastic materials, such as the above copper alloys and aluminum alloys, is mentioned, for example. It is preferable that the material, diameter, and the like of the recoverable rod-shaped member are appropriately determined in consideration of the elasticity, diameter, number, etc. of the hollow cells that constitute the binding unit.

  You may use the rod-shaped member aiming only at the shape prescription | regulation of a recoverable hollow cell and / or a recoverable rod-shaped member. The shape-defining rod-shaped member may be determined in its material, diameter, etc. so that the shape of the restorable hollow cell and / or the restorable rod-shaped member that together form the binding unit can be defined.

  In general, the shape-defining rod-like member is preferably a substantially straight rod-like shape from the viewpoints of the handleability of the cell stack, the design of the fuel cell on which the cell stack is mounted, and the like. It is preferable that the second shape after deformation of the porous hollow cell and / or the shape-defining rod member is a substantially straight rod shape. At this time, the first shape includes a shape in which a substantially straight bar shape is curved in the radial direction.

In the second fuel cell, from the viewpoint of design and the like, normally, a recoverable hollow cell is used as at least one of the hollow cells constituting the binding unit, and a shape-defining rod member is used as the rod member. It is preferable.
In the present invention, as the rod-shaped member constituting one binding unit, both a member having resilience and a member for defining the shape may be used.

  In the second fuel cell, at least one of the wire rod that binds the bundling unit and the rod-shaped member that constitutes the bundling unit may function as an external current collector of the hollow cell that constitutes the bundling unit. In addition to the form in which both the rod-like member and the wire function as the current collector, a form in which only the rod-like member functions as the external current collector, a form in which only the wire that binds the binding units functions as the external current collector, or the like may be used. This is because in the second fuel cell, both the contact pressure between the hollow cell and the wire and the contact pressure between the hollow cell and the rod-like member are kept high.

The bundling method of the bundling unit by the wire is not particularly limited as long as a sufficient tightening force can be applied to the bundling unit, but current collection from the hollow cell, for example, whether the wire has a function as an external current collection material In the case where the wire functions as an external current collector, whether other external current collectors are provided or not, and further, supply of reaction gas to the electrodes provided on the outer surface of the hollow cell is taken into consideration. It is preferable to do.
A typical example is a form in which a single wire is wound spirally around the outer periphery of a bundling unit (see FIGS. 8 and 9). In addition, a net-like member woven with a conductive wire is bound. Examples include a form wound around the outer periphery of the unit with a pressing force applied.

  The arrangement of the hollow cells and the rod-shaped members in the bundling unit is not particularly limited, and may be appropriately determined in consideration of the functions of the rod-shaped members (for shape definition, resilience, current collector, cooling pipe), etc. It is not limited to the form as shown in FIG.

  As in the first fuel cell, the bundling unit bundled with the wire may be fixed to the support plate together with the conductive wire at least at both ends in the axial direction in order to maintain the bundling state with the conductive wire. preferable. Thus, by fixing the binding unit together with the wire, the winding form of the binding unit of the wire can be fixed, and the binding state of the binding unit by the wire can be maintained.

In the bundling unit of the first and second fuel cells of the present invention, the size of the reversible hollow cell and / or the reversible rod-like member displaced by the restoring force is at least in the diameter of the bundling unit. It is preferable that it is more than the size which the electrolyte membrane of a cell occupies. This is because the hollow cell can be reduced in diameter as the electrolyte membrane is made thinner, and the reduction in the binding force of the binding unit can be sufficiently suppressed.
Further, in the binding unit of the first and second fuel cells, the size of the recoverable hollow cell and / or the recoverable rod-like member displaced by the restoring force is at least the diameter of the hollow cell in the binding unit. It is preferable that it is more than the magnitude | size which the electrode provided in the electrolyte membrane and the inner surface and outer surface of this electrolyte membrane occupies. It is possible to allow the diameter reduction of the hollow cell accompanying the thinning of the electrolyte membrane and the electrode due to deterioration of the electrolyte contained in the electrolyte membrane and the electrode, and sufficiently suppress the reduction of the binding force of the binding unit. Because.

  In the fuel cell of the present invention, one or two or more bundling units are suitably connected in parallel or in series so that a desired voltage and current can be obtained from the bundling units composed of the hollow cells connected in parallel as described above. Connect and prepare in the cell stack. Normally, a cell stack is incorporated in a fuel cell in a state of being connected in series or in parallel.

It is a perspective view which shows one example of a hollow type (tube shape) cell used for this invention. It is sectional drawing of the tubular cell shown in FIG. It is a figure which shows one example of a cell stack with which the 1st fuel cell of this invention is equipped. It is a unity unit provided in the cell stack of FIG. It is a figure which shows an example of the 1st shape of a recoverable hollow type cell. It is a figure which shows the other example of a binding unit in a 1st fuel cell. It is a figure which shows the state which fixed the axial direction both ends of the binding unit with the support plate in the 1st fuel cell. It is a figure which shows one example of a binding unit with which the 2nd fuel cell of this invention is equipped. It is a figure which shows the other example of a binding unit with which the 2nd fuel cell of this invention is equipped. It is a figure explaining a time-dependent change of the contact state of the external current collection material of a hollow cell and the outer surface side electrode in the conventional fuel cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hollow electrolyte membrane 2 ... Inner surface side electrode (anode)
3. External electrode (cathode)
4. Internal current collector (anode-side current collector)
5. External current collector (cathode side current collector)
6 ... Hollow cell 7 ... Conductive wire 8 ... Bundling unit 9 ... Rod-shaped member (external current collector and cooling pipe)
10 ... Rod-shaped member (external current collector)
DESCRIPTION OF SYMBOLS 11 ... Wire material 12 ... External current collector connection part 13 ... Support plate 14 ... Through-hole 15 ... Potting material 16 ... External current collector 17 ... Hollow cell 100 ... Cell stack

Claims (32)

A hollow electrolyte membrane, a pair of electrodes provided on an inner surface and an outer surface of the hollow electrolyte membrane, an internal current collector and an external current collector connected to the pair of electrodes, respectively, and at least one end portion thereof A fuel cell comprising a cell stack in which two or more open hollow cells are connected in parallel,
The two or more hollow cells are bundled and bound by at least one conductive wire as the external current collector to form a binding unit;
At least one of the hollow cells constituting the bundling unit is deformed from the original first shape to the second shape and returned to the first shape when a pressing force is applied from the outside. It is a recoverable hollow cell having elasticity that generates force,
The fuel cell according to claim 1, wherein the restorative hollow cell retains a second shape by a tightening force of the conductive wire in the binding unit.   2. The fuel cell according to claim 1, wherein the second shape of the recoverable hollow cell is a substantially straight bar shape, and the first shape is a shape in which the substantially straight bar shape is curved in a radial direction. The bundling unit is a hollow cell constituting the bundling unit, and the shape of the substantially straight bar shape that defines the second shape of the restorable hollow cell by placing the restorable hollow cell along the surface thereof. Including at least one hollow cell for use,
3. The fuel cell according to claim 2, wherein the recoverable hollow cell is deformed into a second shape along a substantially straight bar shape of the shape defining hollow cell.   The fuel cell according to any one of claims 1 to 3, wherein one or more tenths of the two or more hollow cells constituting one binding unit are the recoverable hollow cells.   The fuel cell according to any one of claims 1 to 4, wherein the two or more hollow cells are bound by winding the conductive wire around an outer periphery of the binding unit.   The fuel cell according to any one of claims 1 to 4, wherein the two or more hollow cells are bound together by a net-like member in which the conductive wire is woven.   The fuel cell according to any one of claims 1 to 6, wherein at least both ends of the binding unit in the axial direction are fixed to a support plate together with the conductive wire. A hollow electrolyte membrane, a pair of electrodes provided on an inner surface and an outer surface of the hollow electrolyte membrane, an internal current collector and an external current collector connected to the pair of electrodes, respectively, and at least one end portion thereof A fuel cell comprising a cell stack in which two or more open hollow cells are connected in parallel,
At least one hollow cell is bundled together with at least one rod-like member and bound by at least one wire to form a binding unit;
At least one of the rod-shaped member and the wire is the external current collector,
At least one selected from the hollow cell and the rod-shaped member constituting the binding unit is deformed from the original first shape to the second shape when a pressing force is applied from the outside, and the first It is a recoverable hollow cell or a recoverable rod-like member having elasticity that generates a restoring force to return to the shape,
In the binding unit, the recoverable hollow cell and the recoverable rod-shaped member maintain a second shape by a tightening force of the wire.   The fuel cell according to claim 8, wherein the rod-shaped member has a hollow shape and functions as a cooling pipe through which a cooling medium flows.   At least one of the hollow cells constituting the bundling unit is the restorable hollow cell, and the rod-shaped member has the restorable hollow mold by bringing the restorative hollow cell along the surface thereof. A shape-defining rod-shaped member that defines a second shape of the cell, wherein the recoverable hollow cell is deformed into a second shape along the shape of the shape-defining rod-shaped member. A fuel cell according to claim 1.   11. The fuel cell according to claim 10, wherein the second shape of the recoverable hollow cell is a substantially straight bar shape, and the first shape is a shape obtained by bending the substantially straight bar shape in a radial direction.   The shape-defining rod-like member has higher rigidity than the restorable hollow cell and has a substantially straight rod-like shape, and the wire rod together with the restorable hollow cell while holding the substantially straight rod-like shape. The fuel cell according to claim 10 or 11, wherein the fuel cell is bundled by.   The fuel cell according to claim 12, wherein the binding unit is a form in which two or more of the hollow cells are arranged so as to surround an outer periphery of the shape-defining rod-shaped member.   The fuel cell according to any one of claims 8 to 13, wherein the hollow cell and the rod-like member are bundled by winding the wire around an outer periphery of the binding unit.   The fuel cell according to any one of claims 8 to 13, wherein the hollow cell and the rod-like member are bound together by a net-like member in which the wire is knitted.   The fuel cell according to any one of claims 8 to 15, wherein at least both ends of the binding unit in the axial direction are fixed to a support plate together with the wire. A hollow electrolyte membrane, a pair of electrodes provided on an inner surface and an outer surface of the hollow electrolyte membrane, an internal current collector and an external current collector connected to the pair of electrodes, respectively, and at least one end portion thereof A method for producing a fuel cell comprising a cell stack in which two or more open hollow cells are connected in parallel,
A resilient hollow cell having elasticity that deforms from the original first shape to the second shape and generates a restoring force to return to the first shape when a pressing force is applied from the outside; 2 Prepare one or more hollow cells,
Two or more hollow cells including the restorative hollow cell are bundled and fastened so that the restorative hollow cell can maintain the second shape by at least one conductive wire as the external current collector. Forming a binding unit.   The method for manufacturing a fuel cell according to claim 17, wherein the second shape of the recoverable hollow cell is a substantially straight bar shape, and the first shape is a shape obtained by bending the substantially straight bar shape in a radial direction. As a hollow cell constituting the bundling unit, a substantially straight rod-shaped hollow cell for defining a shape that defines the second shape of the recoverable hollow cell by placing the recoverable hollow cell along the surface thereof. At least prepare,
19. The method of manufacturing a fuel cell according to claim 18, wherein the recoverable hollow cell is deformed into a second shape along a substantially straight bar shape of the shape defining hollow cell.   The method for producing a fuel cell according to any one of claims 17 to 19, wherein at least one-tenth of the hollow cells constituting one binding unit are constituted by the recoverable hollow cells.   21. The method of manufacturing a fuel cell according to claim 17, wherein the two or more hollow cells are bound by winding the conductive wire around an outer periphery of the binding unit.   21. The method of manufacturing a fuel cell according to claim 17, wherein the two or more hollow cells are bound by a net-like member braided with the conductive wire.   23. The method of manufacturing a fuel cell according to claim 17, further comprising a step of fixing the binding unit to a support plate together with the conductive wire at least at both axial ends of the binding unit. A hollow electrolyte membrane, a pair of electrodes provided on an inner surface and an outer surface of the hollow electrolyte membrane, an internal current collector and an external current collector connected to the pair of electrodes, respectively, and at least one end portion thereof A method for producing a fuel cell comprising a cell stack in which two or more open hollow cells are connected in parallel,
Preparing at least one hollow cell, at least one rod-shaped member, and at least one wire, and selecting at least one of the rod-shaped member and the wire as a conductive material as an external current collector; At least one of the hollow cell and the rod-shaped member may be deformed from the original first shape to the second shape and returned to the first shape when a pressing force is applied from the outside. Choose a resilient hollow cell or resilient rod-like member that has elasticity to produce a restoring force to try,
At least one hollow cell and at least one rod-shaped member including the restorable hollow cell or the restorable rod-shaped member are bundled, and the at least one wire is used to make the recoverable hollow cell and the restorable rod-shaped member first. A method of manufacturing a fuel cell, comprising forming a binding unit by tightening and binding to hold the second shape.   The fuel cell manufacturing method according to claim 24, wherein the rod-shaped member has a hollow shape and functions as a cooling pipe through which a cooling medium flows.   As the at least one hollow cell constituting the binding unit, the restorative hollow cell is prepared, and as the rod-shaped member, the restorative hollow cell is provided along the surface thereof. 26. A shape-defining rod-shaped member that defines a second shape of a mold cell is prepared, and the recoverable hollow cell is deformed into a second shape along the shape of the shape-defining rod-shaped member. The manufacturing method of the fuel cell as described in any one of.   27. The method of manufacturing a fuel cell according to claim 26, wherein the second shape of the recoverable hollow cell is a substantially straight bar shape, and the first shape is a shape obtained by bending the substantially straight bar shape in a radial direction.   The shape-defining rod-like member has higher rigidity than the restorable hollow cell and has a substantially straight rod-like shape, and the shape-defining rod-like member holds the substantially straight rod shape, 28. The method for producing a fuel cell according to claim 26, wherein the fuel cell is bundled together with the recoverable hollow cell by the wire.   29. The method of manufacturing a fuel cell according to claim 28, wherein the hollow cells are arranged and bound so as to surround an outer periphery of the shape defining rod-shaped member.   30. The method of manufacturing a fuel cell according to any one of claims 24 to 29, wherein the hollow cell and the rod-shaped member are bound by winding the wire around an outer periphery of the binding unit.   30. The method of manufacturing a fuel cell according to claim 24, wherein the hollow cell and the rod-shaped member are bound together by a net-like member in which the wire is knitted.   32. The method of manufacturing a fuel cell according to claim 24, further comprising a step of fixing the binding unit to a support plate together with the wire at least at both axial ends of the binding unit.

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