JP2005346975A - Fuel cell for small portable electrical apparatus and small portable electrical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell for a small portable electrical apparatus favorably and stably supplying fuel from a fuel container to a cell part. <P>SOLUTION: The fuel cell for the small portable electrical apparatus in which a cell part 2 having a fuel side electrode, an oxygen side electrode and an electrolyte membrane is connected to the fuel container 4 through a connection part 3 has porous bodies 5a-5c supplying fuel from the fuel container 4 to the cell part 2, and the porous body 5b is installed so as to cover at least one of the fuel side electrode 7 and the electrolyte membrane 9 of the cell part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell, particularly a small fuel cell suitable for a small portable electric device, and a small portable electric device using the same.

  In recent years, fuel cells have attracted attention because of their high efficiency as power generation devices. In particular, the application of fuel cells to devices such as video cameras and notebook personal computers (notebook PCs) has recently been expected.

  Examples of fuel cells include phosphoric acid fuel cells, molten carbonate fuel cells, direct methanol fuel cells (DMFC), and direct hydrogen fuel cells (DHFC). The fuel cell is a polymer electrolyte fuel cell (PEFC), such as a direct hydrogen fuel cell (DHFC) or a direct methanol fuel cell (DMFC).

  Examples of application of the direct methanol fuel cell to a small device include Patent Document 1 and Patent Document 2. Examples of a direct methanol battery (DMFC) disclosed in Patent Document 1 are shown in FIGS. In the figure, methanol as fuel is supplied from the fuel storage space 40 to the fuel cell body 32 through the fuel diffusion chamber 34. The fuel cartridge 33 is separated into two chambers, a water storage space 41 and a fuel storage space 40, and stores water from the water recovery chamber 35 of the fuel cell main body 32 in the water storage space 41. In addition, this fuel cell is configured to flow an oxidant gas in a direction perpendicular to the stack 101, and methanol serving as fuel is supplied to the electromotive unit 102 from the outer peripheral surface of the stack by a porous body surrounding the electrode membrane connector. Thus, methanol can be smoothly supplied to the electromotive unit 102 by capillary force without inhibiting the flow of the oxidant gas.

Further, in Patent Document 2, as shown in FIG. 12, a fuel container and a battery unit are arranged on the left and right relative to the device DVC, and are mounted.
However, it is important for a portable device battery to be configured to be as small and light as possible for a fuel cell used in a portable device such as a mobile device such as a digital camera or PDA. In addition, the small portable electric device described in the present invention is not a device that is usually used on a desk like a notebook PC, but basically a camera, a video camera, a PDA, etc., which is used while being held by hand mainly in its usage. Equipment. Since these devices are not necessarily placed on a flat surface during use and may be used in an inclined state, a fuel cell suitable for these devices is the use of the small portable electric device. The form must be considered.

  However, the conventional fuel cell has not been considered so far, and is not sufficient as a fuel cell for a small portable electric device, and depending on the use state, there is a region where the fuel supply is partially insufficient for the catalyst membrane and the electrolyte. This is a factor that accelerates battery performance deterioration. For example, in the conventional fuel cell as shown in FIGS. 8 to 10 of Patent Document 1, the fuel is supplied from the fuel cartridge 33 through the connection point 36 with the fuel diffusion chamber 34. In this case, liquid fuel is introduced. Fuel is introduced by the capillary force generated by adjusting the size of the gap of the passage 110. However, the fuel in the fuel diffusion chamber 34 is normally filled by capillary force. However, when the cell is tilted, it may not be sufficiently filled due to the weight of the fuel. In this state, when methanol fuel is supplied from the end face of the porous body from the fuel diffusion chamber 34 to the fuel electrode 104, the fuel is supplied from a part of the end face of the porous body. In some cases, fuel cannot be supplied uniformly, and sufficient power generation cannot be performed, and battery performance deteriorates depending on the location. Further, since the connection point 36 between the fuel cartridge 33 and the fuel diffusion chamber 34 is also below the uppermost part of the battery, it is difficult to supply fuel effectively until the end.

Further, in the fuel cell 51 in which the fuel container 54 and the battery unit 52 are arranged on the left and right of the shape as shown in FIG. 11, when the fuel supply unit is in the center of the cell body, Depending on the direction of the equipment and the method of use, the methanol solution in the fuel container may not be supplied with sufficient stability to the end, which may cause malfunction of the equipment.
JP-A-6-188008 JP 2002-252014 A

  The present invention has been made in view of such a background art, and in a fuel cell for a small portable electric device in which a battery unit and a fuel container are connected via a connection unit, Regardless of the inclination or operation of the fuel cell depending on the state of use, the fuel cell for a small portable electric device capable of satisfactorily and stably supplying fuel from the fuel container to the battery unit, and the small portable using the fuel cell Provide electrical equipment.

  That is, the present invention is a fuel cell in which a battery part having a fuel side electrode, an oxygen side electrode and an electrolyte membrane and a fuel container are connected via a connecting part, and fuel is supplied from the fuel container to the battery part. A fuel cell for a small portable electric device comprising a porous body to be supplied, wherein the porous body is disposed so as to cover the entire surface of at least one of a fuel-side electrode and an electrolyte membrane of a battery unit. .

It is preferable that the porous body is provided in the fuel container and the battery part, and the porous body of the fuel container and the porous body of the battery part are connected via a connection part.
The pore diameter of the porous body of the battery part is preferably smaller than the pore diameter of the porous body of the fuel container.

The porous body of the fuel container is preferably provided from the fuel supply port of the fuel container to the bottom.
It is preferable that an opening is provided in a connection portion connecting the fuel container and the battery portion, and an opening area of the opening is larger than at least one cross-sectional area of the fuel side electrode, the oxygen side electrode, and the electrolyte membrane.

  Moreover, this invention is a small portable electric apparatus characterized by having said fuel cell for small portable electric apparatuses.

The fuel cell for a small portable electric device of the present invention can stably and stably supply fuel from the fuel container to the battery unit regardless of the inclination or operation of the fuel cell depending on the usage state.
In addition, since the small portable electric device according to the present invention houses the fuel cell that can satisfactorily and stably supply the fuel from the fuel container to the battery unit, the power supply is stable without fluctuation. Can be used.

Hereinafter, the present invention will be described in detail.
A fuel cell for a small portable electric device (hereinafter abbreviated as a fuel cell) of the present invention connects a battery part having a fuel side electrode, an oxygen side electrode and an electrolyte membrane, a fuel container, and the fuel container and the battery part. A fuel cell in which a battery unit and a fuel container are disposed adjacent to each other via the connection unit, the fuel cell having a porous body that supplies fuel from the fuel container to the battery unit, and the porous The body is disposed so as to cover the entire surface of at least one of the fuel-side electrode and the electrolyte membrane of the battery unit.

A small portable electric device of the present invention is a small portable electric device having the above fuel cell.
In the small portable electric device of the present invention, the fuel container of the fuel cell is disposed below the battery part, and has a porous body in the fuel container, and the porous body passes from the fuel supply port of the fuel container to the bottom. It is preferable that the fuel cell is mounted on the small portable electric device so that the battery cell portion and the fuel container of the fuel cell are arranged on the left and right or top and bottom with respect to the small portable electric device. Moreover, it is preferable that the porous body provided in the fuel container is disposed so as to cover the opening of the connection portion.

  According to the fuel cell and the small portable electric device having such a configuration, when a normal small portable electric device is used, the fuel container is located above or below the battery portion, and the fuel is placed below or on the left and right sides of the battery portion. Even when the container is disposed, the fuel solution can be moved by the capillary force of the porous body. In particular, by reducing the pore size of the porous body toward the direction in which the fuel solution is desired to flow, the fuel solution flows in the direction of the pore having the smaller pore diameter. It reaches to every corner.

  By arranging the porous body with the fuel solution spread over the entire surface so as to cover the catalyst membrane or the electrolyte membrane of the electrode of the power generation unit, the fuel is stably supplied to the power generation unit and power generation can be performed without any problem. Will come to be.

  Furthermore, the fuel solution can be obtained by making the opening area of the opening provided in the connecting portion for supplying fuel from the fuel container to the electrode catalyst membrane and the electrolyte membrane equal to or larger than the width of the porous body. Thus, the liquid is sufficiently supplied also to the end portion in the width direction in the porous material, and the entire surface of the porous body is satisfactorily immersed in a fuel solution such as a methanol solution.

  If the porous body immersed in the methanol solution is covered so as to cover the entire surface of the electrode membrane assembly (showing the whole of the fuel side electrode, the oxygen side electrode, and the polymer solid electrolyte), the methanol solution The electrode membrane assembly is constantly supplied uniformly and battery deterioration is suppressed.

  Further, safety is important in a fuel cell for small portable electric devices. In particular, measures against fuel leakage when using harmful fuels such as methanol are important. In particular, when using high-concentration methanol solution, the generation of methanol vapor due to heating may lead to ignition and inhalation of methanol vapor. Take measures to avoid these risks. It is necessary to apply. If at least the fuel container can be arranged at the lower part of the battery part, the connection part connecting the battery part and the fuel container can be positioned above the fuel container, and even when the connection part is broken, it is possible to prevent the fuel solution from leaking, Safety measures can be taken without taking new preventive measures, which is preferable.

  When the fuel cell of the present invention is mounted on a small portable electric device, the fuel is adjusted from the lower fuel container to the upper battery part by adjusting the pore diameter and volume of the porous body, thereby reducing the capillary force of the porous body. Supplied in. In addition, by disposing the porous body in the fuel container up to the bottom of the fuel container, the fuel in the fuel container can be stably supplied to the end with a simple structure without waste. It becomes possible to supply power to the equipment stably for a long time.

  Even when a strong impact is applied to the fuel cell and the battery part and the fuel container are detached, the fuel container is disposed below the small portable electric device, so that the fuel methanol Leakage can be minimized, and fuel fog can be reduced. In this way, the fuel can be used effectively and the safety can be improved.

Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1
FIG. 1 is a schematic view showing a state before connection of a battery part and a fuel container of a fuel cell according to a first embodiment of the present invention, FIG. 1 (a) is a schematic sectional view, and FIG. The figure is shown.

  2A and 2B are schematic views showing a state in which the battery unit and the fuel container of the fuel cell according to the first embodiment of the present invention are connected, FIG. 2A is a schematic cross-sectional view, and FIG. 2B is a schematic front view. FIG. 2 (c) shows a perspective view before connection.

  1 and 2 show the fuel cell of the present invention using methanol as the fuel. FIG. 2C is an overall perspective view of the fuel cell before connection of the battery part and the fuel container. The fuel cell 1 of the present invention has a battery part 2, a fuel container 4, a connection part 3 that connects the battery part 2 and the fuel container 4, and a partition wall 11.

  The fuel container 4 stores methanol fuel as the fuel of the fuel cell 1, and the connection part 3 is provided on the upper part of the fuel container 4. Inside the fuel container 4, a partition wall 11 a is provided so as to be divided into a region 21 for supplying fuel to the battery unit and a region 22 for collecting fuel from the cell unit, and is configured to circulate the fuel solution. Yes. A porous body 5a is formed on the partition wall 11a. It is preferable to form the porous body 5a over the entire surface up to the bottom 12 of the fuel container 4 because the fuel can be used effectively to the end.

The battery unit 2 uses a carbon film in which Pt particles and Pt / RuO ₂ particles are dispersed using a perfluorocarbon sulfonic acid polymer (trade name; Nafion, manufactured by DuPont) as a polymer solid electrolyte 9, and the oxygen side electrode 8 and fuel. A side electrode 7 having a polymer solid electrolyte 9 sandwiched between both electrodes is used as an electrode membrane assembly (MEA), which is fixed to the battery unit 2 and each electrode is in contact with a methanol solution and air. did. When the power generation voltage value of the cell is low, the battery can be set to a predetermined voltage that can drive each device by using it together with a secondary battery such as a lithium battery, but this is disclosed in JP-A-2002-56855. It is also possible to use a cell in which a plurality of cells are arranged so that the same poles are arranged on the same plane.

  In the battery unit 2, a partition wall 11 b is provided corresponding to the partition wall arranged so as to bisect the region in the fuel container 4. The porous body 5b is made larger than the fuel side electrode 7 so as to cover the entire surface of the fuel side electrode 7 (FIG. 1 (a)), and another porous body 5c is connected to the fuel side electrode 7 so as to be connected thereto. It forms in the area other than.

  The porous body is made of materials such as organic or inorganic fibers such as cotton and glass fiber, and synthetic fibers such as acrylic and nylon, and the density of the porous body is determined by the porous body 5a <porous body 5b <porous body. Adjust so as to increase in the order of 5c. The density indicates the proportion of pores in the porous body. The smaller the proportion of pores, the higher the density. Further, the pore diameter of the porous body, the packing density of the material constituting the porous body, and the like can be adjusted and controlled.

  Specifically, in order to generate the necessary capillary force, it is necessary to consider the pore diameter of the porous body, the volume ratio of the pores, and the like. Regarding the pore diameter, although depending on the concentration of the methanol solution, if it is too large, the capillary force becomes small, it becomes difficult to supply the fuel solution to the porous material sufficiently, and if it is too small, the liquid in the porous body There is an appropriate pore size, for example, about 1 μm to 250 μm. Similarly, if the volume of the pores is too large, the strength of the membrane will be weakened, and if the volume ratio is reduced, problems will occur in the flow of the fuel solution. Therefore, the volume ratio of the pores is smaller than the volume of the porous body. About 40 to 70% is preferable. Further, by reducing the hole diameter toward the upper part, the fuel solution in the part having the larger hole diameter in the lower part can be transferred to the part having the smaller hole diameter in the upper part. The pore diameter can be achieved by appropriately adjusting between 1 μm and 250 μm.

  By inclining the pore diameter in this way, methanol fuel flows in a direction in which the pore diameter of the porous body decreases, so that the porous diameter of the pore provided in the fuel container is large. By connecting the body 5a and the porous body 5b having a small pore diameter of the battery portion, methanol fuel is supplied from the fuel container to the fuel side electrode. Even if it is further inclined, the porous bodies 5a and 5b are still connected, and it is like a single porous body with the pore diameter inclined, so that the fuel The fuel side electrode is supplied without interruption.

  In addition, the fuel containers and the partition walls 11a and 11b inside the battery unit are also connected. By connecting the partition walls, a fuel circulation system is formed in the fuel cell as a whole, and unused methanol fuel is supplied to the fuel side electrode. It becomes easy to be supplied.

  Furthermore, the opening area of the opening for supplying fuel from the fuel container 4 to the battery part 2 is made larger than the cross-sectional area of the cell part (electrode or electrolyte membrane), and the cross-sectional area of the porous body is made the fuel electrode side electrode. Or by making it larger than the cross-sectional area of an electrolyte membrane, a fuel can be supplied to an electrode with more uniformity.

  By using the fuel cell having such a configuration, shortage of fuel supply can be suppressed even when the amount of fuel decreases or even when the small portable electric device is used in an inclined state. Further, although not shown in the upper part of the fuel container 4 of the battery unit, a gas vent hole may be provided. When the hole reaches a certain pressure, the valve opens so that it is normally closed.

  FIG. 6 is a schematic view showing that the fuel cell of the present invention is mounted on a fuel cell mounting portion 10 so as to be a small portable electric device with a battery portion 2 at the top and a fuel container 4 at the bottom. Although FIG. 6 shows a video camera as an example, other small portable electric devices can be used similarly. After being installed in the fuel cell mounting part of a video camera, which is a small portable electric device, power is supplied to the device through a terminal provided in the fuel cell mounting unit from a terminal provided in the fuel cell (not shown) by turning on the electric device. The predetermined operation such as photographing can be performed.

Example 2
FIG. 3 is a schematic view showing a fuel cell according to a second embodiment of the present invention.
FIG. 4 is a schematic view showing a state before connection of the battery part and the fuel container of the fuel cell of the second embodiment of FIG.

FIG. 5 is a schematic view showing a state before connection of the battery part and the fuel container of the fuel cell of the second embodiment of FIG.
3 to 5 each show a second fuel cell of the present invention using methanol as a fuel. The difference from the fuel cell of Example 1 is that the positional relationship between the fuel container and the cell part is changed from top to bottom and left and right. The arrangement position is changed. The battery unit 2, the fuel container 4, and the connection part 3 connecting the fuel container and the battery part are configured. The fuel container and the battery unit can be separated, and power can be generated continuously by removing and replacing the fuel container, and can withstand long-term use of equipment.

The battery unit 2 uses a perfluorocarbon sulfonic acid polymer (trade name: Nafion, manufactured by DuPont) as a polymer solid electrolyte, carbon in which Pt particles and Pt / RuO ₂ particles are dispersed, oxygen side electrode, fuel side electrode The solid polymer electrolyte sandwiched between both electrodes was used as an electrode membrane assembly (MEA), and each electrode was configured to be in contact with methanol and air. When the power generation voltage value of the cell is low, the battery can be set to a predetermined voltage that can drive each device by using it together with a secondary battery such as a lithium battery, but this is disclosed in JP-A-2002-56855. It is also possible to use a cell in which a plurality of cells are arranged so that the same poles are arranged on the same plane.

  Although not shown, the water recovery part is made of a material that forms a porous body such as organic or inorganic fibers such as cotton and glass fibers, synthetic fibers such as acrylic and nylon, and the like around the inner surface of the oxygen side electrode container of the battery part. It is arranged so as to be in contact with the entire surface and not to prevent the supply of the oxidant gas to the oxygen side electrode.

  The fuel-side electrode is made of a material that forms a porous body such as organic fibers such as cotton and glass fibers, inorganic fibers, synthetic fibers such as acrylic and nylon, etc. By filling and connecting the fuel container and the battery unit, the fuel is uniformly supplied to the fuel side electrode. If the porous body on the battery side and the porous body of the fuel container are in contact with each other when the fuel container and battery part are connected, the fuel side electrode can be stably and uniformly distributed on the fuel electrode side regardless of the movement of the equipment. Methanol fuel is supplied.

  Further, the opening for supplying fuel from the fuel container to the battery part is made larger than the width of the cell part (catalyst electrode or electrolyte membrane), and the cross-sectional area of the porous body 12 is made larger than the width of the fuel side electrode or electrolyte membrane. By making it wide, the fuel can be supplied to the electrode with better uniformity.

  In addition, a porous body is disposed in the upper part of the fuel container so as to be connected to the battery part. At this time, by increasing the packing density of the porous body on the fuel electrode side of the battery unit as it goes upward, the fuel can be better supplied to the upper part by capillary action.

  Furthermore, by making the opening of the connecting portion larger than the catalyst membrane and the electrolyte membrane, it is possible to supply methanol fuel to the fuel side electrode with higher uniformity. Further, although not shown in the figure, a vent hole is provided in the upper part of the battery part. When the hole reaches a certain pressure, the valve opens so that it is normally closed, and fuel leakage can be prevented.

  FIG. 7 is a schematic diagram in which the fuel cell is arranged on a small portable electric device so as to be a fuel container and a battery part on the left and right sides, and attached to the fuel cell attachment part. In the figure, a video camera is taken as an example. However, it can be similarly used in other small portable electric devices. After mounting on the fuel cell mounting part of a video camera, which is a small portable electrical device, power is supplied to the device from a terminal provided on the fuel cell (not shown) by turning on the power of the electrical device, so that photographing can be performed .

  The fuel cell of the present invention can satisfactorily and stably supply the fuel from the fuel container to the battery unit regardless of the inclination or operation of the fuel cell depending on the usage state. Can be used.

It is the schematic which shows the state before the connection of the battery part and fuel container of the fuel cell of the 1st embodiment of this invention. It is the schematic which shows the state which connected the battery part and fuel container of the fuel cell of the 1st embodiment of this invention. It is the schematic which shows the fuel cell of the 2nd embodiment of this invention. It is the schematic which shows the state before the connection of the battery part and fuel container of the fuel cell of the 2nd embodiment of FIG. It is the schematic which shows the state before the connection of the battery part and fuel container of the fuel cell of the 2nd embodiment of FIG. It is the schematic diagram which mounted | wore the small portable electric device with the fuel cell of this invention. It is the schematic diagram which mounted | wore the small portable electric device with the fuel cell of this invention. It is the schematic which shows the conventional fuel cell. It is the schematic which shows the conventional fuel cell. It is the schematic which shows the conventional fuel cell. It is the model which mounted | wore the small portable electric device with the fuel cell. It is the model which mounted | wore the small portable electric device with the fuel cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Battery part 3 Connection part 4 Fuel container 5a, 5b, 5c Porous body 6 Electrode membrane assembly 7 Fuel side electrode 8 Oxygen side electrode 9 Polymer solid electrolyte 10 Fuel cell mounting part 11a, 11b Partition 12 Bottom 14 Porous material 15 Fuel diffusion mechanism 16 Small portable electric device 21, 22 Region 32 Fuel cell body 33 Fuel cartridge 34 Fuel diffusion chamber 35 Water recovery chamber 36 Connection point 40 Fuel storage space 41 Water storage space

Claims (6)

  A fuel cell in which a battery part having a fuel side electrode, an oxygen side electrode and an electrolyte membrane, and a fuel container are connected via a connection part, comprising a porous body for supplying fuel from the fuel container to the battery part And the porous body is disposed so as to cover the entire surface of at least one of the fuel-side electrode and the electrolyte membrane of the battery unit.   The fuel cell for a small portable electric device according to claim 1, wherein the porous body is provided in a fuel container and a battery part, and the porous body of the fuel container and the porous body of the battery part are connected via a connection part. .   The fuel cell for a small portable electric device according to claim 1 or 2, wherein a pore diameter of the porous body of the battery portion is smaller than a pore diameter of the pore of the porous body of the fuel container.   The fuel cell for a small portable electric device according to any one of claims 1 to 3, wherein the porous body of the fuel container is provided so as to pass from the fuel supply port to the bottom of the fuel container.   The connecting portion connecting the fuel container and the battery portion is provided with an opening, and an opening area of the opening is larger than at least one cross-sectional area of the fuel side electrode, the oxygen side electrode, and the electrolyte membrane. 5. The fuel cell for small portable electric devices according to any one of items 4 to 4.   A small portable electric device comprising the fuel cell for a small portable electric device according to claim 1.

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