JP2008140563A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To relax or ideally uniformize power generation gradient which is reduced from one end side to the other end side of the axial direction of a hollow type cell caused by concentration gradient of a reaction gas circulating in the inner peripheral face side of the hollow type cell, and suppress deterioration of the hollow type cell in the fuel cell equipped with the hollow type cell. <P>SOLUTION: This is a fuel cell equipped with the hollow type cell which comprises a hollow electrolyte membrane, a pair of electrodes installed at the inner peripheral face and the outer peripheral face of the hollow electrolyte membrane, and current collecting materials connected to the pair of electrodes, respectively, and at least one end part of which is opened. At least at one of the inner peripheral face and the outer peripheral face of the hollow type cell, a contact area changing means is installed in which a contact area of the reaction gas per unit area of the inner peripheral face and the outer peripheral face is increased as it goes from the upstream side to the downstream side of the inner peripheral face side gas flow passage of the hollow type cell. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell including a hollow cell having a hollow electrolyte membrane.

  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 that use solid polymer electrolytes as electrolytes are particularly attractive as portable and mobile power supplies because they are easy to downsize and operate at low temperatures. ing.

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

Further, when oxygen is used as the oxidizing agent, the reaction of the formula (2) proceeds at the oxidizing agent electrode.
2H ⁺ + (1/2) O ₂ + 2e ⁻ → H ₂ O (2)
The water produced at the oxidizer electrode 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 a hydrogen electrode and an oxidant electrode is provided on one surface of a planar solid polymer electrolyte membrane and the obtained planar membrane / Flat single cells have been developed in which gas diffusion layers are further provided on both sides of the electrode assembly and sandwiched between flat 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 a number of problems such as technical difficulties and a decrease in power generation efficiency due to deflection and 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 electrodes are respectively provided on an inner peripheral surface side and an outer peripheral surface side of a hollow electrolyte membrane is used as a basic power generation unit (for example, Patent Documents). 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 peripheral surface and the outer peripheral 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 including a hollow cell, a reaction gas (for example, hydrogen as a fuel gas here is used as a fuel gas in the hollow cell), but the oxidant gas such as air is not limited thereto. May be generated) and a reaction gas (for example, air here but may be a fuel gas such as hydrogen) flowing through the outer peripheral surface of the hollow cell reacts to generate electric power. .
Usually, in order to obtain a large voltage, first, a plurality of hollow cells are connected in parallel. 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 2 discloses a tube type fuel cell using a membrane electrode assembly for a tube type fuel cell having a coiled current collector. Patent Document 3 discloses a module having a plurality of tubular composites that collect current by arranging winding or mesh current collectors in contact with the surface of the cathode or anode catalyst layer.

However, the hollow cell has a power generation gradient in the axial direction of the hollow cell. Specifically, the power generation gradient is generated as follows. As described above, in the hollow cell, the fuel gas flowing through the inner peripheral surface side gas flow path and the air flowing through the outer peripheral surface of the hollow cell react to generate electric power. On the other hand, a fuel cell in which hydrogen gas is supplied to the gas flow path on the inner peripheral surface side of the hollow cell and air is supplied to the outer peripheral surface side of the hollow cell in a direction intersecting the axial direction of the hollow cell. In this case, air is supplied to the entire outer peripheral surface of the hollow cell, that is, substantially uniformly to the entire outer peripheral surface of the hollow cell, but the inner peripheral surface side gas flow along the axial direction of the hollow cell. The hydrogen gas flowing through the channel is preferentially consumed on the upstream side due to the reaction with air, and the hydrogen concentration decreases as the gas flows from the upstream side to the downstream side of the inner peripheral surface side gas flow path. Therefore, the concentration of hydrogen gas per unit volume is smaller on the downstream side than on the upstream side on the inner peripheral surface side of the hollow cell, and a concentration gradient is generated.
Since the hollow cell has such a hydrogen gas concentration gradient, the amount of electric power generated by the reaction of hydrogen gas and air (electrochemical reaction amount) is upstream of the gas flow path on the inner peripheral surface side of the hollow cell. It decreases from the side to the downstream side.
As described above, a difference in the amount of electrochemical reaction occurs between the upstream side and the downstream side of the gas flow path on the inner peripheral surface side of the hollow cell. This is likely to cause deterioration of the hollow cell.

JP-T-2004-505417 JP 2005-353484 A Japanese translation of PCT publication No. 2002-539587

  The present invention has been achieved in view of the above circumstances, and in a fuel cell having a hollow cell, the shaft of the hollow cell resulting from the concentration gradient of the reaction gas flowing through the inner peripheral surface of the hollow cell. The purpose is to mitigate or ideally uniform the power generation gradient that decreases from one end side to the other end side of the direction, and to suppress deterioration of the hollow cell.

The fuel cell of the present invention has a hollow electrolyte membrane, a pair of electrodes provided on the inner and outer peripheral surfaces of the hollow electrolyte membrane, and a current collector connected to each of the pair of electrodes, and at least one of the electrodes A fuel cell comprising a hollow cell having an open end,
At least one of the inner peripheral surface and the outer peripheral surface of the hollow cell has a per unit area of the inner peripheral surface or outer peripheral surface as it goes from the upstream side to the downstream side of the gas flow path on the inner peripheral surface side of the hollow cell. Contact area changing means for increasing the contact area of the reaction gas is provided.

  The flow direction of the reaction gas supplied to the outer peripheral surface side of the hollow cell is a direction intersecting the axial direction of the hollow cell.

  In the present invention, at least one of the outer peripheral surface and the inner peripheral surface of the hollow cell is coated with a reactive gas barrier material, and the reactive gas barrier property per unit area of the outer peripheral surface or the inner peripheral surface of the hollow cell. The contact area changing means can be configured by covering so that the covering area ratio of the material decreases from the upstream side to the downstream side of the inner peripheral surface side gas flow path.

  In this case, the reactive gas barrier material may be a current collector and / or a heat exchange member or a resin member in contact with the inner peripheral surface or the outer peripheral surface of the hollow cell.

  For example, the reactive gas barrier material is a linear reactive gas barrier material, and the winding pitch increases as the linear reactive gas barrier material moves from the upstream side to the downstream side of the inner peripheral surface side gas flow path. Thus, it may be wound around the outer peripheral surface of the hollow cell.

  Further, the reactive gas barrier material is a linear reactive gas barrier material whose wire diameter decreases from one end to the other end, or a combination of two or more linear reactive gas barrier materials having different wire diameters. Even if the linear reaction gas blocking material is wound around the outer peripheral surface of the hollow cell so that the wire diameter decreases from the upstream side to the downstream side of the inner peripheral surface side gas flow path. Good.

  The reactive gas barrier material is a linear reactive gas barrier material, and the linear reactive gas barrier material has a weak tightening force as it goes from the upstream side to the downstream side of the inner peripheral surface side gas flow path. It may be wound around the outer peripheral surface of the hollow cell.

  Further, the reactive gas barrier material is a curved plate-like reactive gas barrier material that matches the shape of the inner peripheral surface or outer peripheral surface of the hollow cell, and the plate-like reactive gas barrier material is on the inner peripheral surface side. Along the outer peripheral surface or inner peripheral surface of the hollow cell so that the area of the plate-like reactive gas blocking material in contact with the hollow cell decreases from the upstream side to the downstream side of the gas flow path. May be arranged.

  In the present invention, at least one of the outer peripheral surface and the inner peripheral surface of the hollow cell is coated with the reactive gas barrier material, and the gas permeability of the reactive gas barrier material is the inner peripheral surface side gas. The contact area changing means can be configured by covering the flow path so as to increase from the upstream side to the downstream side.

  In this case, the reactive gas barrier material may be a current collector and / or a heat exchange member or a resin member in contact with the inner peripheral surface or the outer peripheral surface of the hollow cell.

  For example, the reactive gas barrier material is a linear reactive gas barrier material whose gas permeability increases from one end to the other, or two or more linear reactive gas barriers having different gas permeability. The linear reactive gas barrier material is disposed on the outer peripheral surface of the hollow cell so that the gas permeability increases from the upstream side to the downstream side of the inner peripheral surface side gas flow path. It may be turned.

  The reactive gas barrier material is a curved plate-like reactive gas barrier material that matches the shape of the inner peripheral surface or outer peripheral surface of the hollow cell, and the plate-like reactive gas barrier material is on the inner peripheral surface side. You may arrange | position along the outer peripheral surface or inner peripheral surface of the said hollow cell so that gas permeability may become large as it goes downstream from the upstream of a gas flow path.

  According to the present invention, at least one of the inner peripheral surface and the outer peripheral surface of the hollow cell is a unit of the inner peripheral surface or the outer peripheral surface of the hollow cell as it goes from the upstream side to the downstream side of the inner peripheral surface side gas flow path. By providing contact area changing means for increasing the contact area of the reaction gas per area, the reaction gas (fuel gas and oxidant gas) on the upstream side and downstream side of the gas flow passage on the inner peripheral surface side of the hollow cell is provided. ), The power generation gradient from one end to the other end in the axial direction of the hollow cell is moderated, or ideally, the power generation of the hollow cell (electrochemical reaction amount) The hollow cell can be prevented from degrading due to temperature gradient, lack of hydrogen, partial battery, and the like. Therefore, safe and stable power generation is possible in the fuel cell.

The fuel cell of the present invention has a hollow electrolyte membrane, a pair of electrodes provided on the inner and outer peripheral surfaces of the hollow electrolyte membrane, and a current collector connected to each of the pair of electrodes, and at least one of the electrodes A fuel cell comprising a hollow cell having an open end,
At least one of the inner peripheral surface and the outer peripheral surface of the hollow cell has a per unit area of the inner peripheral surface or outer peripheral surface as it goes from the upstream side to the downstream side of the gas flow path on the inner peripheral surface side of the hollow cell. Contact area changing means for increasing the contact area of the reaction gas is provided.

  The contact area changing means is hardware means for preventing at least one partial region of the inner peripheral surface and the outer peripheral surface of the hollow cell from contacting the reaction gas. The supply amount of the reaction gas as the whole fuel cell system does not change depending on the contact area changing means.

In the case of a cell stack in which hollow cells are assembled, normally, the reaction gas supplied to the outer peripheral surface side of the hollow cells is circulated in a direction crossing the axial direction of the hollow cells.
In the present invention, the direction in which the flow direction of the reaction gas supplied to the outer peripheral surface side of the hollow cell intersects with the axial direction of the hollow cell generally refers to the axial direction of the hollow cell. Means that the concentration gradient of the reaction gas supplied to the outer peripheral surface side of the hollow cell does not occur along the axial direction of the hollow cell, that is, the hollow type From the viewpoint that the flow direction of the reaction gas supplied to the outer peripheral surface of the hollow cell does not substantially affect the non-uniformity of the electrochemical reaction amount along the axial direction of the cell, the hollow cell It can be said that the angle direction from about 45 degrees to 90 degrees (straight side) with respect to the axial direction is a direction intersecting the axial direction of the hollow cell.

  When the flow direction of the reaction gas supplied to the outer peripheral surface side of the hollow cell is a direction intersecting the axial direction of the hollow cell, the concentration of the reaction gas supplied to the outer peripheral surface side of the hollow cell Since the gradient does not occur at all or not so much along the axial direction of the hollow cell, the flow direction of the reaction gas supplied to the outer peripheral surface side of the hollow cell is limited in the amount of electrochemical reaction along the axial direction of the hollow cell. There is virtually no effect on uniformity or, if so, not so much. Therefore, considering only the flow direction of the reaction gas on the inner peripheral surface side of the hollow cell, the contact area of the reaction gas on the inner peripheral surface side or the outer peripheral surface side is changed, so that the electric power in the axial direction of the hollow cell is changed. The gradient of the chemical reaction amount can be sufficiently relaxed, and it is usually unnecessary to consider the flow direction of the reaction gas on the outer peripheral surface side of the hollow cell.

Hereinafter, the present invention will be described in detail with reference to the drawings.
(1) First Embodiment A first embodiment of the present invention is connected to a hollow electrolyte membrane, a pair of electrodes provided on the inner and outer peripheral surfaces of the hollow electrolyte membrane, and the pair of electrodes, respectively. At least one of the outer peripheral surface and inner peripheral surface of the hollow cell having a current collector and having at least one end opened is covered with a reactive gas barrier material, and the outer peripheral surface of the hollow cell Alternatively, the coating may be performed so that the ratio of the area covered by the reactive gas blocking material per unit area of the inner peripheral surface decreases from the upstream side to the downstream side of the inner peripheral surface side gas flow path of the hollow cell. It is embodiment by which the contact area change means is comprised.
Using the reactive gas barrier material constituting the contact area changing means, the ratio of the area covered by the reactive gas barrier material per unit area of the outer peripheral surface or inner peripheral surface of the hollow cell is the inner peripheral surface of the hollow cell. By covering at least one of the inner peripheral surface and the outer peripheral surface of the hollow cell so as to decrease from the upstream side to the downstream side of the side gas flow channel, the inner peripheral surface side gas flow channel of the hollow cell As the temperature increases from the upstream side to the downstream side, the contact area of the reaction gas per unit area of the inner peripheral surface or outer peripheral surface can be increased, and the power generation gradient of the hollow cell can be reduced.

The reactive gas barrier material is a material that covers a partial region of at least one of the inner peripheral surface and the outer peripheral surface of the hollow cell and blocks or reduces the supply of the reactive gas to the hollow cell.
If the reactive gas barrier material in the present invention has corrosion resistance and strength that can withstand the operating environment of the fuel cell, an appropriate material can be selected. The reactive gas barrier material may constitute the contact area changing means by a dedicated member, but the contact area changing means may be constituted by giving the function of the reactive gas barrier material to an existing member. Examples of the existing member include a current collector, a heat exchange member that adjusts the temperature of the hollow cell, and a member that also functions as a current collector and a heat exchange member. In addition, as a dedicated member for the reactive gas barrier material, for example, a resin member can be used. For example, acrylic, polycarbonate, polysulfone, and polyether ether ketone resin (PEEK) can be used, and polysulfone and PEEK are preferable from the viewpoint of corrosion resistance and heat resistance. A plurality of different reactive gas barrier materials may be used in combination.
If the shape of the reactive gas barrier material can be arranged on the outer peripheral surface of the hollow cell, or in some cases described later, in close contact with the outer peripheral surface of the hollow cell and the rod-shaped reactive gas barrier material, It is not limited. Examples of the shape include a wire shape (including a wire having a circular cross section and a flat belt shape), a plate shape, a rod shape, a net shape, a sheet shape, a substantially U shape, and combinations thereof.
Thus, when the reactive gas barrier material is a current collector and / or heat exchange member or resin member that contacts the inner peripheral surface or outer peripheral surface of the hollow cell, the inner peripheral surface or outer periphery By arranging the reaction gas blocking material such that the ratio of the contact area by the reaction gas blocking material per unit area of the surface decreases from the upstream side to the downstream side of the gas flow path on the inner peripheral surface side, the contact is achieved. Area changing means is configured.

Specific examples of the first embodiment of the present invention include the following.
In FIG. 1, the reactive gas blocking material is a linear reactive gas blocking material 2 a, and the linear reactive gas blocking material 2 a extends from the upstream side to the downstream side of the inner peripheral surface side gas flow path 1 a of the hollow cell 1. It is a conceptual diagram of the 1st example of 1st Embodiment wound by the outer peripheral surface of this hollow cell 1 so that a winding pitch becomes large as it goes.
Winding usually means that a long linear member is spirally wound around the outer peripheral surface of a hollow cell, and an annular reactive gas blocking material is provided at a desired interval in the axial direction of the hollow cell. A form in which a plurality of (inserted into a hollow cell) is also included. In addition, the hollow cell and the rod-shaped reactive gas barrier material (current collector, heat exchange member, etc.) are juxtaposed in contact with each other so that the linear reactive gas barrier material is connected to the outer peripheral surface of the hollow cell and the rod-shaped material. You may wind so that the outer peripheral surface of a reactive gas barrier material may be bridged.

In the winding pitch, the pitch between adjacent spiral members when a long linear member is spirally wound around the outer peripheral surface of the hollow cell is also the same as that of the annular reactive gas blocking material. The pitch between members is also included.
As for the size of the pitch, the upstream side: a portion of about 1/2 of the axial length of the hollow cell 1 (hereinafter referred to as an intermediate portion): the downstream side at a ratio of 1: 10: 200, the hollow cell 1 It is preferable that the inner circumferential surface side gas flow path 1a increases from the upstream side toward the downstream side, and the arrangement of the linear reaction gas blocking material 2a changes from dense to sparse.

In the first example of the first embodiment, the power generation (electrochemical reaction amount) of the hollow cell 1 is adjusted as follows using the reactive gas barrier material that constitutes the contact area changing means. Hydrogen gas is supplied to the inner peripheral surface side gas flow path 1 a of the hollow cell 1, and air is supplied to the outer peripheral surface side of the hollow cell 1 in a direction intersecting the axial direction of the hollow cell 1. Therefore, the air is supplied substantially uniformly over the entire outer peripheral surface of the hollow cell, that is, the entire outer peripheral surface of the hollow cell, and flows through the inner peripheral surface side gas flow path 1a along the axial direction of the hollow cell. Hydrogen gas is in an environment where it is consumed preferentially by reaction with air upstream rather than downstream. On the other hand, the linear reaction gas blocking material 2a is placed on the outer peripheral surface of the hollow cell 1 so that the winding pitch increases from the upstream side to the downstream side of the inner peripheral surface side gas flow path 1a of the hollow cell 1. Since it is rotated, the contact area ratio by the linear reactive gas barrier material 2a per unit area of the outer peripheral surface decreases as it goes from the upstream side to the downstream side. That is, the ratio of the area covered by the linear reactive gas barrier material 2a per unit area on the outer peripheral surface of the hollow cell 1 decreases from the upstream side to the downstream side of the inner peripheral surface side gas flow path 1a. The air contact area per unit area of the outer peripheral surface increases from the side toward the downstream side. Accordingly, hydrogen gas is not excessively consumed in the reaction with air on the upstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1, and hydrogen is distributed almost evenly from the upstream side to the downstream side. Therefore, the hydrogen gas concentration gradient hardly occurs.
Since the hollow cell 1 in the first example of the first embodiment has almost no hydrogen gas concentration gradient as described above, the amount of electricity generated by the reaction of hydrogen gas and air (electrochemical reaction amount). Is substantially uniform from the upstream side to the downstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1.
On the other hand, conventionally, Patent Document 2 does not describe the distribution of the pitch, thickness and the like of the current collector, and referring to the drawings, the coil current collector is simply formed into a hollow cell at an equal pitch. Since it was only along, the power generation was biased on the upstream side in the axial direction of the inner circumferential gas flow path of the hollow cell. In Patent Document 3, referring to the drawings, a winding or mesh current collector is disposed so as to be in uniform contact with the surface of the cathode or anode catalyst layer to cover the entire surface, thereby correcting the bias in power generation. It ’s difficult.

Further, in the present invention, as shown in FIG. 2 as a second example of the first embodiment, the reactive gas barrier material has a linear reactive gas barrier property in which the wire diameter decreases from one end to the other end. The material 2b or a combination of two or more linear reactive gas barrier materials 2b having different wire diameters, and the linear reactive gas barrier material 2b is a gas flow on the inner peripheral surface side of the hollow cell 1 It may be wound around the outer peripheral surface of the hollow cell 1 so that the wire diameter decreases from the upstream side to the downstream side of the path 1a.
In this case, the linear reaction gas blocking material having a large wire diameter is wound upstream of the inner peripheral surface side gas flow path, and the small wire diameter material is wound downstream and at the same winding pitch as the upstream side. Turn. Since the curve of the outer peripheral surface of the wire becomes gentler as the wire diameter is larger (the outer peripheral surface becomes closer flat), the contact area per unit length of the wire with respect to the outer peripheral surface of the hollow cell 1 increases.

Here, the combination of two or more linear reactive gas barrier materials 2b having different wire diameters is, for example, when the wire diameter of the wire A> the wire diameter of the wire B is 1) or 2) below. Either method is acceptable.
1) A method of winding wire A on the upstream side and winding wire B on the downstream side. In this case, as a method of winding the wire, a long wire may be spirally wound, or an annular wire may be fitted.
2) From the upstream side to the downstream side of the inner peripheral surface side gas flow path 1a, first “two wires A”, then “one wire A and one wire B” and “the wire B A method of arranging them in the order of “two”.
As the size of the wire diameter, the ratio of upstream: intermediate portion: downstream is 50: 5: 1 and decreases from the upstream side to the downstream side of the inner peripheral surface side gas flow path 1a of the hollow cell 1, It is preferable that the linear reactive gas barrier material 2b changes from wide to narrow.

  As in the first example of the first embodiment, for winding, a long linear member is spirally wound around the outer peripheral surface of the hollow cell and a desired interval is set in the axial direction of the hollow cell. A plurality of annular reaction gas blocking materials are provided, and the hollow reaction cells and the rod-shaped reaction gas blocking materials are arranged in parallel so as to be in contact with each other so that the linear reaction gas blocking material is the hollow type. You may wind so that the outer peripheral surface of a cell and the outer peripheral surface of this rod-shaped reactive gas barrier material may be bridged.

In the second example of the first embodiment, the power generation (electrochemical reaction amount) of the hollow cell 1 is adjusted as follows using the reactive gas barrier material constituting the contact area changing means. Hydrogen gas is supplied to the inner peripheral surface side gas flow path 1 a of the hollow cell 1, and air is supplied to the outer peripheral surface side of the hollow cell 1 in a direction intersecting the axial direction of the hollow cell 1. Therefore, the air is supplied substantially uniformly over the entire outer peripheral surface of the hollow cell, that is, the entire outer peripheral surface of the hollow cell, and flows through the inner peripheral surface side gas flow path 1a along the axial direction of the hollow cell. Hydrogen gas is in an environment where it is consumed preferentially by reaction with air upstream rather than downstream. On the other hand, the linear reactive gas barrier material 2b is placed on the outer peripheral surface of the hollow cell 1 so that the wire diameter decreases from the upstream side to the downstream side of the inner peripheral surface side gas passage 1a of the hollow cell 1. Since it is rotated, the contact area ratio by the linear reactive gas barrier material 2b per unit area of the outer peripheral surface decreases as it goes from the upstream side to the downstream side. That is, since the ratio of the area covered with the linear reactive gas blocking material 2b per unit area on the outer peripheral surface of the hollow cell 1 decreases from the upstream side to the downstream side of the inner peripheral surface side gas flow path 1a, The air contact area per unit area of the outer peripheral surface increases from the side toward the downstream side. Accordingly, hydrogen gas is not excessively consumed in the reaction with air on the upstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1, and hydrogen is distributed almost evenly from the upstream side to the downstream side. Therefore, the hydrogen gas concentration gradient hardly occurs.
Since there is almost no hydrogen gas concentration gradient in the hollow cell 1 in the second example of the first embodiment, the amount of electricity generated by reaction between hydrogen gas and air (electrochemical reaction amount). Is substantially uniform from the upstream side to the downstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1.
Compared with the second example of the first embodiment, the first example of the first embodiment can be used easily because the member currently used can be used as it is. The first example of one embodiment is preferred.

In the present invention, as a third example of the first embodiment, the reactive gas barrier material is a linear reactive gas barrier material 2c, and the linear reactive gas barrier material 2c is a hollow cell 1. The hollow cell 1 may be wound around the outer peripheral surface so as to have a weaker tightening force from the upstream side to the downstream side of the inner peripheral surface side gas flow path 1a.
FIG. 3 shows a typical perspective view of the third example of the first embodiment, and shows a schematic cross-sectional view of a state where the linear reaction gas blocking material 2c is wound around a hollow cell. 4 shows. The tightening force of the linear reaction gas blocking material 2c is increased on the upstream side and is decreased on the downstream side. The stronger the tightening force, the more the linear reactive gas blocking material 2c sinks (sinks) into the hollow cell 1, so that the contact area per unit length of the wire to the outer peripheral surface of the hollow cell 1 increases. Note that the winding pitch of the linear reaction gas blocking material 2c is not particularly limited, and may be uniform or varied.
As the magnitude of the tightening force, the ratio of upstream side: intermediate portion: downstream side is 5: 3: 1 and decreases from the upstream side to the downstream side of the inner peripheral surface side gas flow path 1a of the hollow cell 1. It is preferable that the winding force of the linear reaction gas blocking material 2c changes from strong to weak.
In the third example of the first embodiment, an appropriate member that has been conventionally used can be used as the member that winds and fixes the linear reaction gas blocking material 2c. Alternatively, the materials of the hollow cell 1 and the linear reaction gas blocking material 2c can be appropriately selected so that the linear reaction gas blocking material 2c sinks into the hollow cell 1.

  As in the first example of the first embodiment, for winding, a long linear member is spirally wound around the outer peripheral surface of the hollow cell and a desired interval is set in the axial direction of the hollow cell. A plurality of annular reaction gas blocking materials are provided, and the hollow reaction cells and the rod-shaped reaction gas blocking materials are arranged in parallel so as to be in contact with each other so that the linear reaction gas blocking material is the hollow type. You may wind so that the outer peripheral surface of a cell and the outer peripheral surface of this rod-shaped reactive gas barrier material may be bridged.

In the third example of the first embodiment, the power generation (electrochemical reaction amount) of the hollow cell 1 is adjusted as follows using the reactive gas barrier material constituting the contact area changing means. Hydrogen gas is supplied to the inner peripheral surface side gas flow path 1 a of the hollow cell 1, and air is supplied to the outer peripheral surface side of the hollow cell 1 in a direction intersecting the axial direction of the hollow cell 1. Therefore, the air is supplied substantially uniformly over the entire outer peripheral surface of the hollow cell, that is, the entire outer peripheral surface of the hollow cell, and flows through the inner peripheral surface side gas flow path 1a along the axial direction of the hollow cell. Hydrogen gas is in an environment where it is consumed preferentially by reaction with air upstream rather than downstream. On the other hand, the linear reaction gas blocking material 2c is applied to the outer peripheral surface of the hollow cell 1 so that the tightening force becomes weaker as it goes from the upstream side to the downstream side of the gas channel 1a on the inner peripheral surface side of the hollow cell 1. Since it is wound, the ratio of the contact area by the linear reactive gas barrier material 2c per unit area of the outer peripheral surface decreases from the upstream side to the downstream side. That is, the ratio of the area covered by the linear reactive gas blocking material 2c per unit area on the outer peripheral surface of the hollow cell 1 decreases from the upstream side to the downstream side of the inner peripheral surface side gas flow path 1a. The air contact area per unit area of the outer peripheral surface increases from the side toward the downstream side. Accordingly, hydrogen gas is not excessively consumed in the reaction with air on the upstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1, and hydrogen is distributed almost evenly from the upstream side to the downstream side. Therefore, the hydrogen gas concentration gradient hardly occurs.
In the hollow cell 1 in the third example of the first embodiment, since there is almost no hydrogen gas concentration gradient, the amount of electricity generated by the reaction of hydrogen gas and air (electrochemical reaction amount). Is substantially uniform from the upstream side to the downstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1.

  In the first to third examples of the first embodiment described above, for example, the diameter of the winding is reduced by pulling the linear reaction gas blocking material wound in advance in a coil shape from both ends, and After being arranged in the inner peripheral surface side gas flow path, the traction is stopped, and the diameter of the winding is increased according to the recovery force of the linear reaction gas blocking material, and the linear reaction gas blocking material is removed from the inner peripheral surface side gas. It can also be realized on the inner peripheral surface of the hollow cell by being along the inner peripheral surface of the flow path. Alternatively, a linear reaction gas blocking material is wound around the support member to form a shape that fits the inner peripheral surface of the hollow cell, and the linear reaction gas blocking material is removed while maintaining the shape by removing the support member. It can also arrange | position so that the internal peripheral surface of a hollow type cell may be touched.

Further, as shown in FIG. 5, the reactive gas barrier material is a curved plate-shaped reactive gas barrier material 2 d that matches the shape of the outer peripheral surface of the hollow cell 1, and the planar reactive gas barrier material 2 d is The hollow mold 1 is configured so that the area of the plate-like reaction gas blocking material 2d in contact with the hollow cell 1 decreases as it goes from the upstream side to the downstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1. The 4th example of 1st Embodiment arrange | positioned so that the outer peripheral surface of the cell 1 may be mentioned is mentioned.
The shape of the plate-like reactive gas barrier material 2d is such that the arc length of the contact portion in the cross section of the reactive gas barrier material and the hollow cell decreases as it goes from the upstream side to the downstream side of the inner peripheral surface side gas flow path 1a. It can be set as the shape which has the shape which becomes. As a result, the area of the plate-like reaction gas blocking material 2d that is in contact with the hollow cell 1 decreases from the upstream side to the downstream side of the inner peripheral surface side gas flow path 1a.
If necessary, a constraining member (which may be the above-described wire or the like) or an adhesive material for contacting and fixing the plate-like reactive gas blocking material 2d to the hollow cell 1 can be used. Conventionally used ones can be used.

In the fourth example of the first embodiment, the power generation (electrochemical reaction amount) of the hollow cell 1 is adjusted as follows using the reactive gas barrier material constituting the contact area changing means. Hydrogen gas is supplied to the inner peripheral surface side gas flow path 1 a of the hollow cell 1, and air is supplied to the outer peripheral surface side of the hollow cell 1 in a direction intersecting the axial direction of the hollow cell 1. Therefore, the air is supplied substantially uniformly over the entire outer peripheral surface of the hollow cell, that is, the entire outer peripheral surface of the hollow cell, and flows through the inner peripheral surface side gas flow path 1a along the axial direction of the hollow cell. Hydrogen gas is in an environment where it is consumed preferentially by reaction with air upstream rather than downstream. On the other hand, as the plate-like reaction gas blocking material 2d goes from the upstream side to the downstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1, the plate-like reaction gas blocking material 2d moves to the hollow cell 1 of the plate-like reaction gas blocking material 2d. Since it is arranged along the outer peripheral surface of the hollow cell 1 so that the contact area is small, the contact area ratio by the plate-like reactive gas blocking material 2d per unit area of the outer peripheral surface is the upstream. Decreases from the side to the downstream side. That is, the ratio of the area covered by the plate-like reactive gas blocking material 2d per unit area on the outer peripheral surface of the hollow cell 1 decreases from the upstream side to the downstream side of the inner peripheral surface side gas flow path 1a. The air contact area per unit area of the outer peripheral surface increases from the side toward the downstream side. Accordingly, hydrogen gas is not excessively consumed in the reaction with air on the upstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1, and hydrogen is distributed almost evenly from the upstream side to the downstream side. Therefore, the hydrogen gas concentration gradient hardly occurs.
In the hollow cell 1 in the fourth example of the first embodiment, since there is almost no hydrogen gas concentration gradient, the amount of electricity generated by the reaction of hydrogen gas and air (electrochemical reaction amount). Is substantially uniform from the upstream side to the downstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1.

The plate-like reactive gas barrier material 2d described above is a curved plate-like reactive gas barrier material in which the reactive gas barrier material matches the shape of the inner peripheral surface of the hollow cell 1, and the plate-like reactive gas barrier material Of the hollow cell 1 so that the area of the plate-like reaction gas blocking material in contact with the hollow cell 1 decreases as it goes from the upstream side to the downstream side of the gas flow path 1a on the inner peripheral surface side. You may arrange | position so that the inner peripheral surface of the type | mold cell 1 may be followed. Furthermore, a plate-like reactive gas barrier material can be provided on the outer peripheral surface and the inner peripheral surface.
In addition, you may combine the 1st-4th example of 1st Embodiment mentioned above.

Hereinafter, the hollow cell 1 provided in the fuel cell of the present invention will be described.
FIG. 6 is a perspective view showing an embodiment of a hollow cell provided in the fuel cell of the present invention, and FIG. 7 is a schematic cross-sectional view of the hollow cell of FIG. 6 and 7, a hollow cell 1 includes a tubular solid polymer electrolyte membrane (perfluorocarbon sulfonic acid resin membrane) 11 and an anode provided on the inner peripheral surface side of the solid polymer electrolyte membrane 11 (this embodiment). , The fuel electrode 12 and the cathode (air electrode in this embodiment) 13 provided on the outer peripheral surface side. Further, a columnar current collector is disposed on the surface of the anode 12 as the anode-side current collector 14, and a net-like (net-shaped) current collector 15 a made of metal wire and a rod-shaped current collector are disposed on the surface of the cathode 13 as the cathode current collector 15. An electric material 15b is arranged. Although not shown, the reactive gas barrier material 2 in the present embodiment may be knitted into the mesh current collector 15a while being disposed on the outer peripheral surface of the hollow cell 1. Further, the net-like current collector 15a may be the linear reaction gas barrier materials 2a to 2c in the present embodiment.
On the hollow inner peripheral surface of the hollow cell having such a structure (substantially the portion exposed to the inner peripheral surface side gas flow path formed by the groove 14a provided on the outer peripheral surface of the anode current collector 14). By supplying hydrogen gas and air to the outer peripheral surface, fuel or an oxidant is supplied to the anode and cathode to generate electricity.

  The hollow cell 1 of FIG. 7 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. As long as the hollow cell 1 can sufficiently supply the reaction gas to the inner peripheral 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, when a fuel electrode using hydrogen as a fuel is provided as an electrode on the inner peripheral surface side as in this embodiment, hydrogen gas containing almost no non-reactive component is supplied into the hollow of the hollow cell as a fuel gas. In addition, since the diffusibility of hydrogen molecules is high, it is possible to consume the reaction gas supplied in the hollow, so that the reaction gas can be sufficiently supplied even in the hollow portion where one end is sealed. Can do. 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. 6, the hollow cell 1 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 a fuel or an oxidant flows 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, etc. of the tubular solid polymer electrolyte membrane 11 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 perfluorocarbon sulfonic acid resin membrane is preferably thin from the viewpoint of improving proton conductivity, but if it is too thin, the function of isolating gas is lowered and the permeation amount of aprotic hydrogen 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 perfluorocarbon sulfonic acid resin film 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. .

  The electrodes 12 and 13 provided on the inner peripheral surface and the outer peripheral surface of the electrolyte membrane 11 can be formed using an electrode material as used in a polymer electrolyte fuel cell. Usually, an electrode configured by laminating a catalyst layer and a gas diffusion layer in order from the electrolyte membrane side is used.

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 peripheral surface and outer peripheral surface of a hollow electrolyte membrane, the material used for an electrode, etc. may be the same, and may differ.

  The method for providing a pair of electrodes on the inner and outer peripheral 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 peripheral surfaces of the tubular electrolyte membrane to form a catalyst layer, and carbonaceous particles and / or carbonaceous matter are formed on the two catalyst layers. The method of apply | coating and drying the solution containing a fiber and forming a gas diffusion layer is mentioned. At this time, the catalyst layer and the gas diffusion layer are formed so that the hollow portion exists on the inner peripheral surface of the gas diffusion layer formed on the inner peripheral surface side of the electrolyte membrane.

  Alternatively, first, a carbon material such as carbonaceous particles and / or carbonaceous fibers and formed into a tube shape (tubular carbonaceous material) is used as a gas diffusion layer of the inner peripheral surface side electrode (anode), A solution containing an electrolyte and catalyst particles is applied to the outer peripheral surface of the gas diffusion layer and dried to form a catalyst layer of the inner peripheral surface side electrode to produce the inner peripheral surface side electrode, and then the outer peripheral surface of the catalyst layer. A solution containing an electrolyte is applied and dried to form an electrolyte membrane layer, a catalyst layer of an outer peripheral surface side electrode (cathode) is formed on the outer peripheral surface of the electrolyte membrane layer, and a solution containing a carbon material on the outer peripheral surface of the catalyst layer There is also a method of forming a gas diffusion layer of the outer peripheral surface side electrode by applying and drying. 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.

Next, the current collector that can be provided in the fuel cell of the present invention will be described. The current collector is connected to electrodes provided on the inner peripheral surface and outer peripheral surface of the hollow electrolyte membrane of the hollow cell, and takes out the current of each cell.
The current collector of the present invention is not particularly limited as long as it is made of an electrically conductive material. Examples of the metal used as the current collector include at least one metal selected from Al, Cu, Fe, Ni, Cr, Ta, Ti, Zr, Sm, In, and the like, or those such as stainless steel The alloy is 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 shape of the current collector is not particularly limited, and may be a linear shape or a cylindrical shape in addition to a columnar shape, a wire shape, a rod shape, and is made of a sheet material such as a spring-like metal wire, a metal foil, a metal sheet, or a carbon sheet. Things can also be applied. The thickness of the wire and the braid density, the thickness of the rod-shaped current collector, etc. are not particularly limited.

  As a form of the current collector, for example, an anode side current collector (in this embodiment, an internal current collector disposed on the inner surface side electrode surface) 14 as shown in FIG. 6 has an outer diameter in contact with the inner peripheral surface of the hollow cell 1. A groove 14a extending in the axial direction (longitudinal direction) of the hollow cell 1 is formed on the outer peripheral surface thereof. A gap between the groove 14a and the inner peripheral surface side electrode 12 serves as an inner peripheral gas flow path 1a for supplying hydrogen gas. As the groove 14a, at least one groove extending in the axial direction (longitudinal direction) of the hollow cell 1 is necessary, and grooves having various patterns or orientations on the outer peripheral surface of the hollow cell 1 as necessary. It is formed.

  Moreover, as the cathode side current collector (in this embodiment, the external current collector disposed on the surface of the outer surface side electrode), the hollow cells 1 and the rod-shaped current collectors 15b are alternately arranged in parallel, and the outer circumferences of both are arranged. A net-like current collector 15a, which is a part of the cathode-side current collector 15 woven with a metal wire so as to cover the surface, is formed. The net-like current collector 15a made of a metal wire is formed so that the plurality of hollow cells 1 and the rod-shaped current collector 15b of each hollow cell are integrated, and the cathode (outer surface side electrode) and each rod of each hollow cell. Metal wires are knitted so as to contact the current collector 15b, and the mesh-like current collector 15a is shared by a plurality of hollow cells. At this time, the cathode side current collectors (15a, 15b) of the hollow cells form a connection network electrically connected to each other.

As a form using a mesh current collector, in addition to the mesh current collector 15a described above, a form in which a metal wire is woven so as to integrate one hollow cell and one rod current collector (without forming a connection network) is also possible. Alternatively, a metal wire is knitted so as to integrate a plurality of hollow cells and a single rod current collector, and the current of the plurality of hollow cells passes through the metal wire of the mesh current collector to form a single rod current collector. You may form the connection network formed so that it may gather on a body.
Moreover, as the external current collector, only the net-like current collector 15a made of a metal wire may be used without using the rod-shaped current collector 15b. At this time, a metal wire may be knitted so as to integrate a plurality of hollow cells, and each hollow cell may share this network current collector (each current collector is connected to each other). The rod-shaped current collector 15b may have a tube shape having a hollow portion through which fluid or gas can flow, and a heat medium for cooling or heating the cells may be circulated in the hollow portion of the rod-shaped current collector.
Also, on the anode side (hollow cell inner surface side), a connection network in which anode-side current collectors of the respective hollow cells are electrically connected to each other may be formed.
These current collectors are fixed on the electrodes with a conductive adhesive such as a carbon-based adhesive or an Ag paste as necessary.
A reactive gas blocking material or a conductive member may be interposed between the hollow cell 1 and the current collector. As the material of the conductive member, the same material as the conductive material can be used.

Next, the heat exchange member that can be provided in the fuel cell of the present invention will be described.
The heat exchange member of the present invention is a member for heat exchange of the hollow cell. The heat exchange member of the present invention may be any member that can contact at least a partial region along the axial length of the hollow cell and can implement the present invention, but is usually provided in parallel with the hollow cell. It is preferable that the pipe has one heat medium supply port and one heat medium discharge port. This is because the seal structure for fixing the heat exchange member can be simplified by using the heat exchange member having such a structure. In addition, when there is one inlet and outlet of the heat exchange member, the heat exchange member may have a branched structure from the inlet to the outlet, and it may be a single tube. There may be. Especially, in this invention, it is preferable that the said heat exchange member consists of one pipe | tube. This is because the arrangement of the cooling pipes can be simplified.
The heat exchange member is connected to a heat exchanger (not shown), the heat medium circulates through the heat exchanger, and the heat medium circulates through the heat exchange member. The heat medium in the heat exchange member exchanges heat with the hollow cell, and then is collected in the heat exchanger through the flow path, returned to the original heat state, supplied to the heat exchange member again, and circulated. .

  The heat exchange member is formed of a material having thermal conductivity that allows the hollow cell to be cooled or heated to a predetermined temperature range when a heat medium flows through the heat exchange member. Examples of such materials include common metals such as Cu, Al, Ti, Pt, Ag, and Au, and alloys or clad materials of combinations of these metals.

The heat exchange member may impart insulating properties to at least a part thereof as necessary. This is because, depending on the arrangement of the hollow cell and the heat exchange member and the type of the heat medium, it is necessary to prevent electric leakage from the heat exchange member and the heat medium. On the other hand, when the heat exchange member functions as a current collector for a hollow cell, it is necessary to impart conductivity to at least a part of the heat exchange member. Also in this case, if necessary, insulation is imparted to the inner peripheral surface of the flow path of the cooling unit in order to prevent leakage from the heat exchange member or the heat medium.
The outer diameter of the cooling pipe varies depending on the size of the hollow cell and is not particularly limited, but is usually in the range of 0.5 to 2 mm.

As the heat medium, a fluid generally used as a coolant or a heat medium heater or a boiler can be used, and may be a liquid or a gas. For example, examples of the liquid include water and ethylene glycol, and examples of the gas include air. From the viewpoint of the cooling effect, a liquid coolant is usually preferable. As the liquid coolant, ethylene glycol can be preferably used from the viewpoints of convection, freezing resistance, and corrosivity. Moreover, when heating a cell, heat medium oil, sand, etc. can be used as a heat medium.
In addition, you may add suitably the antifreeze etc. for preventing the freezing of the coolant under freezing point etc. in a heat medium.

As the heat exchanger, a general heat exchanger can be used. Examples thereof include those that dissipate heat by ventilating a cooling fan, those that dissipate heat by circulating a solvent serving as a heat medium, those that use an air-cooling system that uses air as the outside air, and electric heaters. Among these, a radiator that radiates heat in the air is preferable.
A reactive gas barrier material or a heat conductive member may be interposed between the hollow cell 1 and the heat exchange member. As the material of the heat conductive member, the same material as that of the heat exchange member can be used.

(2) Second Embodiment In the second embodiment of the present invention, at least one of the outer peripheral surface and the inner peripheral surface of the hollow cell is covered with a reactive gas barrier material, and the outer peripheral surface of the hollow cell Alternatively, the contact area changing means is configured by covering the inner peripheral surface such that the gas permeability of the reactive gas blocking material increases from the upstream side to the downstream side of the inner peripheral surface side gas flow path. It is an embodiment.
By using the reactive gas barrier material constituting the contact area changing means, the gas permeability of the reactive gas barrier material is increased as it goes from the upstream side to the downstream side of the gas flow path on the inner peripheral surface side of the hollow cell. Further, by covering at least one of the inner peripheral surface and the outer peripheral surface of the hollow cell, the inner peripheral surface or the outer peripheral surface as it goes from the upstream side to the downstream side of the inner peripheral surface side gas flow path of the hollow cell. The contact area of the reaction gas per unit area can be increased, and the power generation gradient of the hollow cell can be reduced.

  The reactive gas barrier material used in the second embodiment is special to the first embodiment in terms of gas permeability, but the shape, material, pitch, etc. are the same as those in the first embodiment. can do. Moreover, the hollow cell, current collector, and heat exchange member in the second embodiment can be the same as those in the first embodiment. The material, shape, pitch, and the like of each member can be the same as in the first embodiment.

Specifically, the second embodiment includes the following forms.
As a first example of the second embodiment, the reactive gas barrier material is a linear reactive gas barrier material whose gas permeability increases from one end to the other end, or the gas permeability is It is a combination of two or more different linear reactive gas barrier materials, and the linear reactive gas barrier material is gas permeable as it goes from the upstream side to the downstream side of the inner peripheral surface side gas flow path of the hollow cell 1. There is an embodiment in which the coil is wound around the outer peripheral surface of the hollow cell so as to be large.
In this case, a linear reactive gas blocking material having a low gas permeability is wound upstream of the inner circumferential surface side gas flow path, and the high gas permeability is wound downstream and at the same winding pitch as the upstream side. Wrap around.
Here, the linear heat conducting member whose gas permeability increases from one end to the other end in the longitudinal direction is applied with, for example, water-repellent layer inks having different concentrations from one end to the other end in the longitudinal direction. This can be realized by a technique using a gradient of the porous shape of the heat conductive member. Examples of the linear reactive gas barrier material having a low gas permeability include a plated wire and a clad wire such as gold. Examples of the linear reactive gas barrier material having high gas permeability include water-repellent treated wires obtained by subjecting plated wires and cladding wires to water-repellent treatment, carbon fibers, and the like.

  As in the first example of the first embodiment, for winding, a long linear member is spirally wound around the outer peripheral surface of the hollow cell and a desired interval is set in the axial direction of the hollow cell. A plurality of annular reaction gas blocking materials are provided, and the hollow reaction cells and the rod-shaped reaction gas blocking materials are arranged in parallel so as to be in contact with each other so that the linear reaction gas blocking material is the hollow type. You may wind so that the outer peripheral surface of a cell and the outer peripheral surface of this rod-shaped reactive gas barrier material may be bridged.

In the first example of the second embodiment, the power generation (electrochemical reaction amount) of the hollow cell 1 is adjusted as follows using the reactive gas barrier material constituting the contact area changing means. Hydrogen gas is supplied to the inner peripheral surface side gas flow path 1 a of the hollow cell 1, and air is supplied to the outer peripheral surface side of the hollow cell 1 in a direction intersecting the axial direction of the hollow cell 1. Therefore, the air is supplied substantially uniformly over the entire outer peripheral surface of the hollow cell, that is, the entire outer peripheral surface of the hollow cell, and flows through the inner peripheral surface side gas flow path 1a along the axial direction of the hollow cell. Hydrogen gas is in an environment where it is consumed preferentially by reaction with air upstream rather than downstream. On the other hand, linear reactive gas barrier material 2? Is wound around the outer peripheral surface of the hollow cell 1 so that the gas permeability increases from the upstream side to the downstream side of the gas channel 1a on the inner peripheral surface side of the hollow cell 1, so that the upstream side The air contact area per unit area of the outer peripheral surface increases from the downstream side to the downstream side. Accordingly, hydrogen gas is not excessively consumed in the reaction with air on the upstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1, and hydrogen is distributed almost evenly from the upstream side to the downstream side. Therefore, the hydrogen gas concentration gradient hardly occurs.
Since the hollow cell 1 in the first example of the second embodiment has almost no hydrogen gas concentration gradient as described above, the amount of electricity generated by the reaction of hydrogen gas and air (electrochemical reaction amount). Is substantially uniform from the upstream side to the downstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1.

  In the first example of the second embodiment described above, for example, the diameter of the winding is reduced by pulling a linear reaction gas blocking material wound in advance in a coil shape from both ends, and the inner periphery of the hollow cell is reduced. The traction is stopped after being arranged in the surface side gas flow path, and the diameter of the winding is increased in accordance with the recovery force of the linear reaction gas blocking material, and the linear reaction gas blocking material is moved to the inner peripheral surface side gas flow path. It can also be realized on the inner peripheral surface of the hollow cell by being along the inner peripheral surface. Alternatively, a linear reaction gas blocking material is wound around the support member to form a shape that fits the inner peripheral surface of the hollow cell, and the linear reaction gas blocking material is removed while maintaining the shape by removing the support member. It can also arrange | position so that the internal peripheral surface of a hollow type cell may be touched.

As a second example of the second embodiment, the reactive gas barrier material is a curved plate-shaped reactive gas barrier material that matches the shape of the outer peripheral surface of the hollow cell 1, and the plate-shaped reactive gas barrier Embodiment in which the conductive material is arranged along the outer peripheral surface of the hollow cell so that the gas permeability increases as it goes from the upstream side to the downstream side of the gas flow path on the inner peripheral surface side of the hollow cell 1 Is mentioned.
Here, the plate-like heat conducting member having high gas permeability can be realized by a technique such as using a plurality of types of metal meshes having different meshes.
If necessary, a constraining member (which may be the above-described wire or the like) or an adhesive material for contacting and fixing the plate-like reactive gas barrier material to the hollow cell 1 can be used. Can be used.

In the second example of the second embodiment, the power generation (electrochemical reaction amount) of the hollow cell 1 is adjusted as follows using a reactive gas barrier material constituting the contact area changing means. Hydrogen gas is supplied to the inner peripheral surface side gas flow path 1 a of the hollow cell 1, and air is supplied to the outer peripheral surface side of the hollow cell 1 in a direction intersecting the axial direction of the hollow cell 1. Therefore, the air is supplied substantially uniformly over the entire outer peripheral surface of the hollow cell, that is, the entire outer peripheral surface of the hollow cell, and flows through the inner peripheral surface side gas flow path 1a along the axial direction of the hollow cell. While the hydrogen gas is in an environment where it can be preferentially consumed by the reaction with air on the upstream side rather than on the downstream side, the plate-like reactive gas blocking material is the gas flow path 1a on the inner peripheral surface side of the hollow cell 1. Since the gas permeability of the plate-like reactive gas barrier material 2d increases along the outer circumferential surface of the hollow cell 1 as it goes from the upstream side to the downstream side, the downstream from the upstream side The contact area of air per unit area of the outer peripheral surface increases toward the side . Accordingly, hydrogen gas is not excessively consumed in the reaction with air on the upstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1, and hydrogen is distributed almost evenly from the upstream side to the downstream side. Therefore, the hydrogen gas concentration gradient hardly occurs.
Since the hollow cell 1 in the second example of the second embodiment has almost no hydrogen gas concentration gradient as described above, the amount of electric power generated by the reaction of hydrogen gas and air (electrochemical reaction amount). Is substantially uniform from the upstream side to the downstream side of the gas flow path 1a on the inner peripheral surface side of the hollow cell 1.

The plate-like reactive gas barrier material described above is a curved plate-like reactive gas barrier material in which the reactive gas barrier material matches the shape of the inner peripheral surface of the hollow cell 1, and the plate-like reactive gas barrier material is On the inner peripheral surface of the hollow cell 1, the gas permeability of the plate-like reaction gas blocking material increases as it goes from the upstream side to the downstream side of the gas channel 1 a on the inner peripheral surface side of the hollow cell 1. It may be arranged along. Furthermore, a plate-like reactive gas barrier material can be provided on the outer peripheral surface and the inner peripheral surface.
In addition, you may combine the 1st and 2nd example of 2nd Embodiment mentioned above. Moreover, you may combine 1st Embodiment mentioned above and 2nd Embodiment.

The fuel cell according to the present invention is obtained by connecting two or more cell stacks in parallel or in series, each including at least two integrals of the hollow cell 1, the current collector and the heat exchange member in parallel or in series.
Specifically, as shown in FIG. 8, the cell stack 30 includes two or more hollow cells 1, a current collector and a heat exchange member integrated product (cell module 29). At both ends of the cell stack 30, gas manifolds 31 a and 31 b that circulate hydrogen gas in the hollow of the hollow cell 1 and heat medium manifolds 32 a and 32 b that circulate the heat medium in the heat exchange member 2 are provided. And a current collector (not shown) that collects the charges generated in each hollow cell 1. Partition walls 35a and 35b (external restraint members described above) disposed between the hydrogen gas flow path 33 in the gas manifolds 31a and 31b and the oxidant gas flow path 34 between the gas manifolds 31a and 31b. Through holes into which the cell modules 29 can be inserted are provided at predetermined intervals, and the plurality of cell modules 29 are inserted into the through holes of the partition walls 35a and 35b facing each other. Thus, they are aligned at predetermined intervals and in parallel with each other in the longitudinal direction. The partition walls 35a and 35b are subjected to a potting process for pouring a potting material and sealing a region including the periphery of the through hole on the side of the oxidizing gas channel, and the cell module 29 inserted into the through hole is fixed integrally. Has been.
In the cell stack 30, the hydrogen supplied to the cell stack 30 via the gas manifold (for example, 31 a) on the inlet side passes through the inner peripheral surface side gas flow path 1 a of each hollow cell 1, and the oxidant The oxygen in the air supplied from the gas flow path 34 to the outer peripheral surface of the hollow cell 1 and the electrolyte membrane through the electrolyte membrane, hydrogen and the like not used in the electrochemical reaction are gas manifolds on the outlet side. (For example, 31b). In the cell stack 30, one of the current collectors is electrically connected to the negative electrode side current collector 14 shown in FIG. 7 of the hollow cell 1, and the other is positive electrode side current collector 15 (15a, 15b). ) Is electrically connected to (collects) the electric charges generated in the plurality of hollow cells 1. In addition, when the reactive gas barrier material 2 described above also serves as the positive electrode side current collector, it is electrically connected to the positive electrode side current collector together with the positive electrode side current collector 15 (not shown).
A plurality of such cell stacks 30 are accommodated in an outer container and connected in series or in parallel to form a fuel cell. There are no particular limitations on the supply of fuel and oxidant, current collection of the module, connection method, and the like.

It is a perspective view which shows the 1st example of 1st Embodiment in this invention. It is a perspective view which shows the 2nd example of 1st Embodiment in this invention. It is a perspective view which shows the 3rd example of 1st Embodiment in this invention. It is a typical sectional view showing the 3rd example of a 1st embodiment in the present invention. It is a perspective view which shows the 4th example of 1st Embodiment in this invention. It is a perspective view which shows one example of the hollow cell with which the fuel cell of this invention is equipped. It is sectional drawing of the hollow type cell of FIG. It is an external view which shows roughly the example of 1 form of the cell stack of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hollow cell 1a ... Inner peripheral side gas flow path 2a, 2b, 2c, 2d ... Reaction gas blocking material 11 ... Hollow electrolyte membrane (perfluorocarbon sulfonic acid membrane)
12 ... Anode (inner surface side electrode)
13 ... Cathode (outer peripheral surface side electrode)
14 ... Anode-side current collector (internal current collector)
14a ... Groove 15 (15a, 15b) ... Cathode side current collector (external current collector)
DESCRIPTION OF SYMBOLS 29 ... Cell module 30 ... Cell stack 31 (31a, 31b) ... Gas manifold 32 (32a, 32b) ... Heat medium manifold 33 ... Hydrogen gas flow passage 34 ... Oxidant gas flow passage 35 (35a, 35b) ... Partition

Claims (12)

A hollow electrolyte membrane, a pair of electrodes provided on an inner peripheral surface and an outer peripheral surface of the hollow electrolyte membrane, and a current collector connected to each of the pair of electrodes, and at least one end thereof being open A fuel cell comprising a type cell,
At least one of the inner peripheral surface and the outer peripheral surface of the hollow cell has a per unit area of the inner peripheral surface or outer peripheral surface as it goes from the upstream side to the downstream side of the gas flow path on the inner peripheral surface side of the hollow cell. A fuel cell comprising contact area changing means for increasing the contact area of the reaction gas.   2. The fuel cell according to claim 1, wherein a flow direction of the reaction gas supplied to the outer peripheral surface side of the hollow cell is a direction intersecting with an axial direction of the hollow cell.   At least one of the outer peripheral surface and inner peripheral surface of the hollow cell is covered with a reactive gas barrier material, and the reactive gas barrier material per unit area of the outer peripheral surface or inner peripheral surface of the hollow cell is 3. The fuel cell according to claim 1, wherein the contact area changing means is configured by covering so that a covering area ratio decreases from an upstream side to a downstream side of the gas flow path on the inner peripheral surface side. .   The fuel cell according to claim 3, wherein the reactive gas barrier material is a current collector and / or a heat exchange member or a resin member that is in contact with an inner peripheral surface or an outer peripheral surface of the hollow cell.   The reactive gas barrier material is a linear reactive gas barrier material, and the winding pitch of the linear reactive gas barrier material increases from the upstream side to the downstream side of the inner peripheral surface side gas flow path. The fuel cell according to claim 4, wherein the fuel cell is wound around an outer peripheral surface of the hollow cell.   The reactive gas barrier material is a linear reactive gas barrier material whose wire diameter decreases from one end to the other, or a combination of two or more linear reactive gas barrier materials having different wire diameters. The linear reactive gas blocking material is wound around the outer peripheral surface of the hollow cell so that the wire diameter decreases from the upstream side to the downstream side of the inner peripheral surface side gas flow path. 5. The fuel cell according to 4.   The reactive gas barrier material is a linear reactive gas barrier material, and the linear reactive gas barrier material has a weak tightening force as it goes from the upstream side to the downstream side of the inner peripheral surface side gas flow path. The fuel cell according to claim 4, wherein the fuel cell is wound around an outer peripheral surface of the hollow cell.   The reactive gas barrier material is a curved plate-shaped reactive gas barrier material that matches the shape of the inner peripheral surface or outer peripheral surface of the hollow cell, and the planar reactive gas barrier material is an inner peripheral surface side gas flow path. Is arranged along the outer peripheral surface or inner peripheral surface of the hollow cell so that the area of the plate-like reaction gas blocking material in contact with the hollow cell decreases as it goes from the upstream side to the downstream side. The fuel cell according to claim 4.   At least one of the outer peripheral surface and the inner peripheral surface of the hollow cell is covered with a reactive gas barrier material, and the gas permeability of the reactive gas barrier material is downstream from the upstream side of the inner peripheral surface side gas flow path. 3. The fuel cell according to claim 1, wherein the contact area changing means is configured by covering so as to increase as it goes.   10. The fuel cell according to claim 9, wherein the reactive gas barrier material is a current collector and / or a heat exchange member or a resin member that contacts an inner peripheral surface or an outer peripheral surface of a hollow cell.   The reactive gas barrier material is a linear reactive gas barrier material whose gas permeability increases from one end to the other, or two or more linear reactive gas barrier materials having different gas permeability The linear reaction gas blocking material is wound around the outer peripheral surface of the hollow cell so that the gas permeability increases as it goes from the upstream side to the downstream side of the inner peripheral surface side gas flow path. The fuel cell according to claim 10.   The reactive gas barrier material is a curved plate-shaped reactive gas barrier material that matches the shape of the inner peripheral surface or outer peripheral surface of the hollow cell, and the planar reactive gas barrier material is an inner peripheral surface side gas flow path. The fuel cell according to claim 10, wherein the fuel cell is disposed along an outer peripheral surface or an inner peripheral surface of the hollow cell so that gas permeability increases from an upstream side to a downstream side.

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