Patent Application
20110268995
The present invention relates to a storing structure for a fuel cell unit which generates electric power by being supplied with a liquid fuel, such as direct methanol fuel cell, and an electronic apparatus, particularly a mobile apparatus, in which a fuel cell unit is mounted.
Mobile apparatuses such as cellular phones, notebook-sized personal computers, portable audio-visual apparatuses, personal digital assistants (PDAs), etc. have been spreading rapidly. Attendant on the enhancement of functions of these mobile apparatuses, there has been an increasing demand for small-sized high-capacity power sources which enable the mobile apparatuses to be used for a longer time. At present, secondary batteries are used as the power sources. In regard of the secondary batteries, reductions in size and weight and enhancement of energy density are being advanced. In the mobile apparatuses, however, power consumptions are tending to increase due to the addition thereto of new functions such as a digital camera function, a function for reception of one-segment broadcasting, etc. Accordingly, there is a request for a power source for longer-time use as compared with secondary batteries.
Fuel cells are classified into various types, depending on differences in electrolyte and the like. As a representative type of fuel cell, there is known a polymer electrolyte fuel cell (PEFC) in which a solid polymer electrolyte is used as the cell electrolyte. The polymer electrolyte fuel cells are suited to use as driving power sources for electronic apparatuses because they can be manufactured at reduced costs, can be easily reduced in size, thickness and weight, and are high in cell performance, particularly in output density. The polymer electrode fuel cells include not only those in which hydrogen is used as fuel but also those comparatively newly developed ones in which methanol or natural gas is modified to produce hydrogen for use as fuel. In recent years, the direct methanol fuel cells (DMFCs) have been developed in which methanol is supplied directly to the fuel cell as fuel for power generation.
In the direct methanol fuel cell, a membrane and electrode assembly (MEA), having an electrolyte membrane and a pair of electrodes united on a base plate, and a flat plate-shaped separator, having a fuel channel at one-side surface and an oxidant gas channel at the other-side surface, are alternately stacked, and an aqueous methanol solution is supplied into the fuel channel whereas air is supplied into the oxidant gas channel, whereby a power generating reaction is effected on the electrolyte membrane. In the direct methanol fuel cell, water and carbon dioxide are generated as reaction products, and they are discharged.
There have been proposed an active-type (forced air intake type) fuel cell in which the supply of the fuel to the fuel cell and discharge of the power generating reaction products (water, carbon dioxide) are effected by use of an accessory such as a pump, and a passive-type (open-type) fuel cell in which natural diffusion of the aqueous methanol solution and air or the like is utilized and an accessory is not used. In the past, use of a fuel cell as a charging cradle (mount) for a cellular phone has been proposed by Japanese Patent No. 4005608.
Other than the system in which a secondary battery inside a cellular phone is charged by use of a fuel cell in the outside of the cellular phone as described in Japanese Patent No. 4005608, a system has recently been being put into practical use in which a fuel cell, for example, the above-mentioned direct methanol fuel cell, is incorporated in a cellular phone and is used as a power source for the cellular phone.
In the case of a fuel cell, the output voltage of a unit cell serving as a power generating part is low, and, therefore, a stack structure in which the membrane electrode assemblies and the separators are alternately stacked is adopted. The stack structure, however, is accompanied by an increase in the thickness of the fuel cell unit and is, therefore, not desirable as a power source for mobile apparatuses. In order to solve this problem, Japanese Patent Laid-open No. 2004-324012 describes a thin-type fuel cell unit of a structure in which a plurality of unit cells (unit fuel cells) are arranged two-dimensionally on a thermoplastic resin sheet and the plurality of unit cells are connected in series.
In the case of a thin-type fuel cell, for example, direct methanol fuel cell, an aqueous methanol solution as fuel is supplied from a fuel cartridge to a fuel electrode (hereinafter referred to as anode electrode). Oxygen (air) is supplied through an opening in an outer casing to an air electrode (hereinafter referred to as cathode electrode). It is necessary that the operating conditions such as the quantity of the aqueous methanol solution supplied, the quantity of air supplied, and power generation temperature are maintained in designed optimum states.
In the case of a mobile apparatus which is portable and in which components are mounted in high density, however, it may be difficult to keep the operating conditions optimum. One problem is generated when air is taken in. Specifically, at the time of intake of air from the exterior through a casing, if the open area ratio for air intake is not appropriate or if the opening for air intake is closed, the intake air quantity would become deficient, leading to a lowering in the output of the fuel cell.
Another problem is the problem of the heat generated in the fuel cell due to a reaction or the like. The heat generated by the fuel cell may persist inside the casing, whereby the temperature of the membrane and electrode assembly is raised, and the output of the fuel cell is lowered through drying.
Accordingly, it is an object of the present invention to provide a fuel cell storing structure, and an electronic apparatus, wherein operating conditions of a fuel cell can be favorably maintained as initially set.
In order to solve the above-mentioned problem, the present invention provides a fuel cell storing structure including:
a fuel cell which includes an anode electrode supplied with a fuel, a cathode electrode supplied with air, a membrane and electrode assembly held between the anode electrode and the cathode electrode, and an anode plate-shaped member stacked on the anode electrode;
a fuel supplying part configured to reserve the fuel and supply the anode electrode with the fuel;
a casing which defines a fuel cell storing space for storing the fuel cell; and
a heat transfer sheet one end portion of which is set in contact with an outer surface of the anode plate-shaped member and an other end portion of which is extended to the exterior of the fuel cell storing space and set in contact with an inner surface of the casing.
The present invention provides a fuel cell storing structure including:
a fuel cell which includes an anode electrode supplied with a fuel, a cathode electrode supplied with air, a membrane and electrode assembly held between the anode electrode and the cathode electrode, and a cathode plate-shaped member stacked on the cathode electrode and provided with an air vent hole;
a fuel supplying part configured to reserve the fuel and supply the anode electrode with the fuel;
a casing which defines a fuel cell storing space for storing the fuel cell; and
a metal film formed on an inner surface of that casing portion which faces the cathode plate-shaped member.
Preferably, a claw configured to press the cathode plate-shaped member against the metal film is provided in the fuel cell storing space.
Preferably, a claw configured to press the cathode plate-shaped member against the metal film through a heat-conductive elastic member is provided in the fuel cell storing space.
The present invention provides a fuel cell storing structure including:
a fuel cell which includes an anode electrode supplied with a fuel, a cathode electrode supplied with air, a membrane and electrode assembly held between the anode electrode and the cathode electrode, and an anode plate-shaped member stacked on the anode electrode;
a fuel supplying part configured to reserve the fuel and supply the anode electrode with the fuel;
a casing which defines a fuel cell storing space for storing the fuel cell;
a circuit board stacked on the anode plate-shaped member; and
an electric energy accumulating part stacked on the circuit board.
Preferably, one end portion of a heat transfer sheet is held between the anode plate-shaped member and the circuit board, and an other end portion of the heat transfer sheet is extended to the exterior of the fuel cell storing space and set in contact with an inner surface of the casing.
Preferably, a heat-conductive gel is packed between a surface on one side of the circuit board and an opposed surface.
The present invention provides an electronic apparatus including:
a fuel cell which includes an anode electrode supplied with a fuel, a cathode electrode supplied with air, a membrane and electrode assembly held between the anode electrode and the cathode electrode, and an anode plate-shaped member stacked on the anode electrode;
a fuel supplying part configured to reserve the fuel and supply the anode electrode with the fuel;
a casing which defines a fuel cell storing space for storing the fuel cell; and
a wiring board supporting thereon a circuit supplied with power source from the fuel cell,
which are stored inside the casing;
wherein one end portion of a heat transfer sheet is set in contact with an outer surface of the anode plate-shaped member, and an other end portion of the heat transfer sheet is extended to the exterior of the fuel cell storing space and set in contact with an inner surface of the casing.
The present invention provides an electronic apparatus including:
a fuel cell which includes an anode electrode supplied with a fuel, a cathode electrode supplied with air, a membrane and electrode assembly held between the anode electrode and the cathode electrode, and an anode plate-shaped member stacked on the anode electrode;
a fuel supplying part configured to reserve the fuel and supply the anode electrode with the fuel;
a casing which defines a fuel cell storing space for storing the fuel cell; and
a wiring board supporting thereon a circuit supplied with power source from the fuel cell,
which are stored inside the casing;
wherein a metal film making contact with the cathode plate-shaped member is formed on an inner surface of a portion of the casing.
The present invention provides an electronic apparatus including:
a fuel cell which includes an anode electrode supplied with a fuel, a cathode electrode supplied with air, a membrane and electrode assembly held between the anode electrode and the cathode electrode, and an anode plate-shaped member stacked on the anode electrode;
a fuel supplying part configured to reserve the fuel and supply the anode electrode with the fuel;
a casing which defines a fuel cell storing space for storing the fuel cell;
a circuit board stacked on the anode plate-shaped member; and
an electric energy accumulating part stacked on the circuit board.
The present invention provides a fuel cell storing structure including:
a fuel cell which includes an anode electrode supplied with a fuel, a cathode electrode supplied with air, a membrane and electrode assembly held between the anode electrode and the cathode electrode, and a cathode plate-shaped member stacked on the cathode electrode and provided with air vent holes;
a fuel supplying part configured to reserve the fuel and supply the anode electrode with the fuel;
a casing which defines a fuel cell storing space for storing the fuel cell;
an air intake hole formed in a casing portion facing the cathode plate-shaped member; and
a projection formed at an inner surface of the casing portion so as to secure a gap between the cathode plate-shaped member and the casing portion which face each other.
Preferably, the fuel cell has a plurality of rectangular power generating parts arranged two-dimensionally, the plurality of power generating parts being connected in series;
the air vent holes in the plurality of power generating parts are partitioned by a grid pattern; and
the projection is a grid pattern rib formed correspondingly to the grid pattern.
Preferably, another projection is further formed in each of regions in which the respective air vent holes of the plurality of power generating parts are formed, the another projection being formed correspondingly to a position where the air vent hole is not formed.
Preferably, a porous part is disposed between the cathode plate-shaped member and the casing portion which face each other.
The present invention provides an electronic apparatus including:
a fuel cell which includes an anode electrode supplied with a fuel, a cathode electrode supplied with air, a membrane and electrode assembly held between the anode electrode and the cathode electrode, and a cathode plate-shaped member stacked on the cathode electrode and provided with air vent holes;
a fuel supplying part configured to reserve the fuel and supply the anode electrode with the fuel; and
a wiring board supporting thereon a circuit supplied with power source from the fuel cell is mounted,
which are stored inside a casing;
wherein an air intake hole is formed in a casing portion facing the cathode plate-shaped member; and
a projection configured to secure a gap between the cathode plate-shaped member and the casing portion which face each other is formed at an inner surface of the casing portion.
The present invention provides a fuel cell storing structure including:
a fuel cell which includes an anode electrode supplied with a fuel, a cathode electrode supplied with air, a membrane and electrode assembly held between the anode electrode and the cathode electrode, and a cathode plate-shaped member stacked on the cathode electrode and provided with an air vent hole;
a fuel supplying part configured to reserve the fuel and supply the anode electrode with the fuel;
a casing which defines a fuel cell storing space for storing the fuel cell;
an air intake hole formed in a casing portion facing the cathode plate-shaped member; and
a plurality of raised parts formed at an outer surface of the casing portion.
Preferably, the plurality of raised parts are provided in that region in the periphery of the casing portion in which the air intake hole is not formed.
Preferably, the raised parts are formed in the periphery of an operating part of an operating switch so as to be higher than the operating part.
The raised parts represent a mark, a character, or a symbol.
The present invention provides an electronic apparatus including:
a fuel cell which includes an anode electrode supplied with a fuel, a cathode electrode supplied with air, a membrane and electrode assembly held between the anode electrode and the cathode electrode, and a cathode plate-shaped member stacked on the cathode electrode and provided with an air vent hole;
a fuel supplying part configured to reserve the fuel and supply the anode electrode with the fuel;
a wiring board supporting thereon a circuit supplied with power source from the fuel cell,
which are stored inside a casing;
wherein an air intake hole is formed in a casing portion facing the cathode plate-shaped member; and
a plurality of raised parts are formed at an outer surface of the casing portion.
According to the present invention, the operating conditions of a fuel cell can be kept in optimum states. The invention ensures that intake of air can be performed favorably. The invention ensures that release of heat from the fuel cell can be accelerated. Further, a fuel cartridge can be held securely. The residual fuel amount in the fuel cartridge can be checked easily.
Now, one embodiment of the present invention will be described below, referring to the drawings. Incidentally, while the embodiment described below is a preferable specific example of the present invention and is accompanied by various restrictions which are preferable technically, the scope of the invention is not to be limited to or by the embodiment, unless it is especially described in the following description that the restriction is limitative of the invention.
One embodiment of the present invention is a cellular phone in which a direct methanol fuel cell is incorporated as a fuel cell. As shown in
A key operating part 101 and a liquid crystal display 102 are mounted to the upper case 100. In practice, the key operating part 101 and the liquid crystal display 102 are preliminarily assembled as respective units, and the key operating part unit and the liquid crystal display unit are mounted to the upper case 100.
A fuel cell unit storing part 201 as a space for storing a fuel cell unit therein and a fuel cartridge storing part 202 as a space for storing a fuel cartridge therein are provided on the back side of a principal surface of the lower case 200. The fuel cell unit storing part 201 and the fuel cartridge storing part 202 are partitioned from each other by a lower case reinforcement rib 207. The lower case 200 defining the fuel cell unit storing part 201 is integrally provided with a multiplicity of small holes for intake of air into the fuel cell, a rib for securing strength of the casing, and the like. The fuel cartridge 300 is inserted into the fuel cartridge storing part 202 through an insertion port 203 provided in a side surface of the lower case 200.
The fuel cartridge 300 is formed from a light-transmitting synthetic resin material, and has a box-like shape which is comparatively small in thickness. An aqueous methanol solution as a fuel is enclosed in the inside of the fuel cartridge 300. The residual amount of the fuel in the fuel cartridge 300 can be externally checked through a residual fuel amount check window 206. In this case, for easy checking of the residual amount, an illumination unit 301 is provided in the vicinity of the fuel cartridge storing part 202.
The fuel cell unit 400 includes two plate-shaped fuel cells 401a and 401b. Each of the fuel cells has a configuration in which, for example, six power generating parts are arranged two-dimensionally and are connected in series with one another. In the power generating parts, membrane electrode assemblies each of which has a structure in which an electrolyte membrane is held between an anode electrode and a cathode electrode are connected to one another while using an insulating sheet or the like, each of the membrane electrode assemblies is further held between a cathode plate (cathode plate-shaped member) and an anode plate (anode plate-shaped member) composed of a current collector and an insulating layer, and a fuel pump for supplying the fuel to the anode electrode is provided. As the current collector, a punching metal or mesh of stainless steel, aluminum or the like is used.
A fuel supply pipe 402 is provided for supplying the fuel from the fuel cartridge 300 to the fuel cell unit 400. A fuel cell control circuit board 403 is stacked on the fuel cell unit 400, and a secondary battery (e.g., lithium ion secondary battery using a polymer electrolyte) 404 is stacked on the fuel cell control circuit board 403. This embodiment is configured to be of the hybrid power source type in which both the fuel cell unit 400 and the secondary battery 404 are used as a power source. An electric double layer capacitor may be used in place of the secondary battery 404. The secondary battery 404 or the electric double layer capacitor functions as an electric energy accumulating part.
A main substrate 501 is mounted to the secondary battery 404 through a frame 500. The frame 500 is a resin molding, and is provided for holding the secondary battery 404, protecting the main substrate 501, and the like purposes. Circuit components needed for a cellular phone, such as a radio circuit, a signal processing LSI, a control CPU (Central Processing Unit), a memory, a liquid crystal display driving circuit, a one-segment broadcasting reception circuit, etc. are mounted on the main substrate 500. A main antenna unit 502 and a sub antenna unit 503 are disposed respectively at both end portions of the main substrate 501. For instance, the main antenna unit 502 is for the cellular phone, and the sub antenna unit 503 is for the one-segment broadcasting reception.
A pipe connection part 402a for supplying the fuel from the fuel cartridge 300 to the fuel cell unit 400, and a pipe branching part 402b for supplying the fuel to the two fuel cells 401a and 401b, are provided. A fuel supply pipe 402 is composed of the pipe connection part 402a and the pipe branching part 402b. As an example, a configuration may be mentioned in which supply of the fuel is conducted by a pump provided in each fuel cell, while intake of air is conducted by natural diffusion.
A heat transfer sheet 411 is disposed in contact with the anode plate in the fuel cell unit 400. The heat transfer sheet 411 is so sized as to make contact with the whole area of the anode sheet in the fuel cell unit 400. A heat transfer sheet extension part 412 is provided at one end of the heat transfer sheet 411. Further, a heat transfer sheet 413 connected to the heat transfer sheet 411 is provided. The heat transfer sheets 411, 412 and 413 are provided for releasing the heat generated in the fuel cell unit 400. Specifically, the heat generated in the fuel cell unit 400 is released to a low-temperature portion of the lower case 200 through the heat transfer sheets 411 and 412, and, simultaneously, the heat is released to a low-temperature portion of the main substrate 501 through the heat transfer sheets 411 and 413.
The fuel cell control circuit board 403 and the secondary battery 404 are sequentially stacked on that surface of the fuel cell unit 400 which is on the anode plate side, with the heat transfer sheet 411 sandwiched therebetween. Incidentally, in
As shown in
The DC-DC converter (IC) boosts an input voltage from one of the fuel cells V1 and V2 to a voltage of about 4 V, which is approximately equal to the voltage of the secondary battery V3. When a load current is small, a current is supplied from the fuel cell V1 or V2 to the load W, and, simultaneously, a charging current is supplied to the secondary battery V3. When the load current is large, the output voltage of the fuel cells is lowered, and efficiency is lowered. In such an instance, therefore, the load current is supplied from the secondary battery V3. In this manner, by the hybrid configuration using the fuel cell and the secondary battery, it is possible to cope with a rapid increase in load current and to prevent the power source device from being enlarged.
As schematically shown in
As will be described later, the fuel cartridge 300 is provided at its one face with a step extending in the insertion direction so that the fuel cartridge 300 can be inserted only when it is oriented properly in relation to the insertion port 203. The fuel cartridge detection switch 302 is provided in the fuel cartridge storing part 202. An operating part of the detection switch 302 is depressed by an end face of the fuel cartridge 300 inserted, whereby the mounting of the fuel cartridge 300 is detected. Other than the configuration in which the operating part is depressed by the end face, a configuration may also be adopted in which the operating part of the detection switch is operated by an upper surface of the fuel cartridge 300.
As shown in
An output of the fuel cell 401 is inputted to the control circuit 303, and is boosted to a predetermined output voltage by the DC-DC converter, as above-mentioned. An output voltage from the control circuit 303 and an output voltage of the secondary battery 404 are supplied, in parallel, to a load on the main substrate 501. By the structure in which the fuel cartridge detection switch 302 is provided and the detection signal is supplied to the control circuit 303, a situation in which the pump 304 is operated in the absence of the fuel cartridge 300 mounted in position and which leads to degradation of the performance of the power generating parts in the fuel cell 401 is prevented from occurring.
As shown in detail in
Further, the auxiliary member 305 is provided, at its portion for contact with the upper surface of the fuel cartridge 300, with a claw 306 which is elastic and functions as a lock part. The lower case 200 is provided, near the window part 205, with a lock receiving part (e.g., a recessed shape) 204. Upon mounting of the fuel cartridge 300, the claw 306 gets into the claw receiving part 204, whereby the mounted state of the fuel cartridge 300 is securely held, and the fuel cartridge 300 can be prevented from chattering or slipping off. In the case of taking the fuel cartridge 300 out of the cellular phone, the auxiliary member 305 of the fuel cartridge 300 is pushed down through the window part 205, whereby the locking between the claw 306 and the claw receiving part 204 is released.
As shown in
Incidentally, in the fuel cell storing part 202 of the lower case 200, as shown in
As shown in
When the operating button 309 is depressed by the user at the time of checking the residual fuel amount, the illumination switch is turned ON, and the light emitting diode of the illumination unit 301 is turned ON. A structure is adopted in which the illumination light from the light emitting diode illuminates the fuel cartridge 300 from the side surface and is reflected by an inner surface of the casing. The light from the light emitting diode is diffused by the fuel in the fuel cartridge 300, so that the part of the fuel becomes bright. Consequently, the residual amount can be easily checked through the residual fuel amount check window 206. If the light emitting element is provided on the bottom surface side of the fuel cartridge 300, the problem of an increase in thickness would arise. In the present embodiment, illumination from a lateral side is adopted, so that an increase in thickness can be avoided. Furthermore, since the residual amount of the fuel can be checked in the condition where the fuel cartridge 300 is mounted in the cellular phone, it is unnecessary to dismount the fuel cartridge for the purpose of checking the residual fuel amount.
[Release of Heat from Fuel Cell]
The fuel cells 401a and 401b generate heat upon reactions therein. If the heat persists inside the casing of the cellular phone, a problem arises would arise in which the membrane and electrode assembly is brought to a temperature higher than an appropriate temperature, and the membrane electrode assembly is dried, leading to a lowering in the output voltage. Furthermore, a situation in which the casing is brought to a high temperature is dangerous. Therefore, it is necessary to release (dissipate) the heat generated in the fuel cell unit 400. In one embodiment, a configuration is adopted in which the heat generated in the fuel cell unit 400 is transferred to the casing (the upper case 100 and the lower case 200), preferably, to a comparatively low temperature portion of the casing, and is then radiated from the casing to the exterior.
For releasing the heat, good heat transfer between the fuel cell unit 400 and the casing must be secured. For accelerating the release of heat from the fuel cell unit 400, there are a configuration in which an electrically insulating heat transfer sheet is used and a configuration in which the inner surface of the lower case 200 is plated with a metal having good thermal conductivity, for example, copper and heat is released through the copper plating.
As shown in
As each of the transfer sheet 411 and the extension part 412, for example, a heat-conductive graphite sheet can be used. The heat-conductive graphite sheet is made of graphite, of which thermal conductivity in the plane directions is higher than thermal conductivity in the thickness direction, and by which heat can be efficiently conducted from the fuel cell unit 400 to the lower case 200. That part of the lower case 200 which is put in close contact with the inner side of the heat transfer sheet extension part 412 is on the lower side of the storing part 202 for the fuel cartridge 300. In addition, an end portion of the main substrate 501 is located on the upper side of that part. Therefore, no heat generating part is present in the vicinity of that part. Accordingly, that part is a comparatively low temperature portion. By transferring the heat to the low temperature portion of the casing, the heat can be released effectively.
As shown in
Further, a configuration may be adopted in which, as shown in
As shown in
As another configuration for heat release, a configuration will be described in which the inner surface of the lower case 200 is plated with a metal having good thermal conductivity, for example, copper. As schematically shown in
In the example shown in
In order that the heat generated in the fuel cell unit 400 is effectively released (dissipated) through the metal film 211 and the lower case 200, it is necessary for the fuel cell unit 400 and the metal film 211 to be in close contact with each other. As shown in
As another configuration, as shown in
As shown in
Further, a heat transfer gel sheet 417 is disposed between the fuel cell control circuit board 403 and the secondary battery 404. The parts mounting surface of the fuel cell control circuit board 403 has ruggedness (projections and recesses) in an extent of about 1 mm. Therefore, even when the fuel cell control circuit board 403 and the secondary battery 404 are in contact with each other, heat is little conducted therebetween. The heat transfer gel sheet 417 is used as a heat transfer blank material for absorbing the ruggedness (projection and recesses). The heat transfer gel sheet 417 has high thermal conductivity in the thickness direction.
As the heat transfer blank material, there can be used elastomers such as silicone, rubber, etc. and gelled blank materials. Further, blank materials obtained by admixing these blank materials with carbon or a metal such as aluminum so as to enhance thermal conductivity can also be used. As for the hardness of the blank material after mounting in position, the blank material may be kept in the gel form or may be solidified. As for the configuration of the blank material, an electrically insulating sheet or an insulating layer is provided on the surface of the blank material. A sheet-shaped processed product or a material to be packed between the circuit board 403 and the secondary battery 404 is used. Furthermore, the circuit board 403 and the secondary battery 404 may be united by integral molding or by filling (packing).
Thus, the heat generated in the fuel cell unit 400 is released through the heat transfer sheet 415 to the lower case 200. In addition, the heat is released (dissipated) in the thickness direction through the heat transfer sheet 415, the fuel cell control circuit board 403 and the heat transfer gel sheet 417 and through the secondary battery 404. Furthermore, although the secondary battery 404 is lowered in performance in a low-temperature environment, the transfer of the heat arising from the fuel cell to the secondary battery 404 makes it possible to prevent the performance from being lowered.
As above-mentioned, the heat generated in the fuel cell unit 400 is transmitted to the comparatively low temperature portion of the casing through the heat transfer blank material, such as the heat transfer sheet 411, or through the metal film 211, and is radiated from the casing to the exterior. Further, with the heat transmitted to the secondary battery 404 in the thickness direction, the release (dissipation) of heat is accelerated. All of these configurations for release of heat may not necessarily be adopted. For example, as the configuration for heat transfer to the casing, one of the heat transfer sheet and the metal film may be adopted.
That casing portion of the lower case 200 which faces the cathode plate of the fuel cell unit 400 is provided with a multiplicity of air intake holes 215, as uniformly as possible. The open area ratio of the air intake holes 215 in the casing portion is set in the range of 20 to 40%, from the viewpoint of both its purpose and strength of the case. Further, for maintaining the strength in the case where the air intake holes 215 are formed, the lower case 200 is formed with ribs at positions opposed to the boundaries of the power generating parts of each fuel cell. Further, it is desirable that the layout pattern of the air intake hole 215 coincides, as much as possible, with the pattern of slit-like openings formed in the cathode plate. Furthermore, in-plane diffusion of air can be secured by providing a gap between the cathode plate and the inner surface of the lower case 200. Consequently, even in the case where the air intake holes 215 are partly closed, the quantity of air (oxygen) supplied to the fuel cell unit 400 can be prevented from becoming deficient.
As shown in
As shown in
The air intake structure will now be described more in detail.
The lower case 200 is formed with air intake holes 215 similar in shape to the cathode holes 421, at positions corresponding to the cathode holes 421 in the condition where the fuel cells 401a and 401b are stored in the fuel cell storing part. As indicated by shading in
Furthermore, as shown in
In the sectional view along line T1-T1, on the upper side, of the region where the air intake holes 215 are formed, there is shown an illumination switch button 309 constituting the illumination unit 301. With the illumination switch button 309 depressed to the lower side, the illumination switch is turned ON, and the light emitting diode provided on the illumination unit substrate 308 is turned ON, whereby the fuel cartridge 300 is illuminated. Raised parts 220a and 220b are formed respectively at the left and right sides of the illumination switch button 309. The tip of the illumination switch button 309 is located below the top portions of the raised parts 220a and 220b. The raised parts 220a and 220b prevent the illumination switch from being turned ON when the lower case 200 is placed on a surface of a desk or the like.
At the position of line T2-T2, on the lower side, of the region where the air intake holes 215 are formed, there are formed a badge (mark) 221 of the maker, the sales company or the like and a logo 222 in the state of being projected like relief. In the sectional view along line T2-T2 in
When the cellular phone is placed on a flat surface of a desk or the like, with the lower case 200 on the lower side, a gap is secured beneath the lower case 200 owing to the raised parts 220a and 220b as well as the badge 221 and the logo 222. Therefore, the air intake holes 215 can be prevented from being closed. Thus, a situation in which the quantity of oxygen taken in is deficient and the output of the fuel cell is thereby lowered can be obviated.
The present invention is not limited to the above-described embodiment, and various modifications are possible based on the technical thought of the invention. For instance, a porous member, for example, a porous sheet may be disposed in the gap between the cathode plate of the fuel cell unit 400 and the lower case 200. The porous sheet has a function of preventing intrusion of dust, without hampering intake of air. Furthermore, the present invention is applicable not only to cellular phones but also to such portable electronic apparatuses as PDA, portable game machines, etc.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-175345 | Jul 2008 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2009/062197 | 6/26/2009 | WO | 00 | 7/5/2011 |
