The present application claims priority from Japanese application serial JP 2005-245798 filed on Aug. 26, 2005, the content of which is hereby incorporated by reference into this application.
The present invention relates to a cell holder, a fuel cell module, and electronic equipment.
As power source for mobile terminals and notebook personal computers, fuel cells are under development. The fuel cells in general include fuel electrodes, air electrodes, and MEAs (Membrane Electrode Assemblies) including electrolyte membranes sandwiched between the fuel electrodes and air electrodes. Additionally, the fuel cells include current collectors sandwiching the MEAs (for example, see the patent document 1).
Conventionally, in accordance with, e.g., a rated voltage of electronic equipment, when a plurality of MEAs are arranged in series or in parallel, each of both ends of an electrical conductor such as a lead wire are attached to current collectors of different MEAs to electrically connect a plurality of the MEAs to each other. The plurality of the MEAs electrically connected in series or in parallel are integrated with each other to be one battery pack. The battery pack is mounted on a cell holder of the electronic equipment.
[Patent document 1]
JP-1997-092323A (Paragraph numbers 0014 to 0017)
However, the electrical conductor such as the lead wire is attached to the current collectors to connect a plurality of the MEAs in series or in parallel by, e.g., screws or welding. Therefore, the attachment takes a long time and a lot of effort.
In view of the above problem, the present invention is achieved. An object of the present invention is to provide a cell holder in which a plurality of MEAs can be connected in series or in parallel without using, e.g., lead wires, a fuel cell module mounted on the cell holder, and electronic equipment including the cell holder.
As means for solving the problem, a cell holder of the present invention, on which a fuel cell module is mounted, the fuel cell module including a plurality of power units having membrane electrode assemblies generating electrical power by use of liquid fuel, and a case for integrating these power units with each other. In the fuel cell module, at least a part of each of anodes and cathodes of all the power units is a contact portion for electrical connection from outside the case for integrating the plurality of the power units with each other. The cell holder includes terminals corresponding to the number of the anodes and cathodes of the power units. The terminals come in contact with and are electrically connected to the contact portions of the anodes and cathodes when the fuel cell module is mounted on the cell holder. In addition, the cell holder includes a connecting portion for electrically connecting the terminal corresponding to the contact portion of the anode of one of the power units and the terminal corresponding to the contact portion of the cathode of the other power unit.
In the cell holder, the terminals of the cell holder come in contact with and electrically connected to the anode of one power unit of the fuel cell module and the cathode of the other power unit of the fuel cell module when the fuel cell module is mounted on the cell holder. Accordingly, MEAs of a plurality of the power units can be electrically connected in series through the terminals and the connecting portion.
The fuel cell module of the present invention is mounted on the cell holder. The fuel cell module is electrically connected to the terminals of the cell holder. The fuel cell module includes a plurality of the power units having membrane electrode assemblies generating electrical power by use of liquid fuel, and the case for integrating these power units with each other. The anodes and cathodes of the power units have the contact portions in contact with and electrically connected to the terminals when the fuel cell module is mounted on the cell holder.
The fuel cell module is mounted on the cell holder, so that the anodes and cathodes of the power units can be electrically connected to each other.
According to the present invention, a plurality of the MEAs does not need to be electrically connected to each other in the fuel cell module. The fuel cell module is mounted on the cell holder, so that the MEAs in the fuel cell module can be electrically connected to each other. Accordingly, the attachment of electrical conductors is unnecessary for electrically connecting the MEAs to each other. The time and effort for production of the fuel cell module can be decreased, and a cost for the production can be reduced. Additionally, a space for the electrical conductors in the fuel cell module is unnecessary. Thus, the fuel cell module can be made smaller.
Embodiments of the present invention are explained below in reference to the drawings.
A case where a fuel cell module 3 is a direct methanol fuel cell (DMFC) is explained here. A case where the fuel cell module 3 includes two power units 4a, 4b (see
[Structure of the Cell Holder]
As shown in
The fuel cell module 3 is detachably mounted on the body 10. The body 10 is a container containing the terminals 11, the control substrate 12, the electric double layer capacitor 13, the USB connector 14, and the fuel cartridge 15. For example, the body 10 is made of plastic. A bottom plate (not shown) of the body 10 has a plurality of air flow holes (not shown). The bottom plate is in contact with a bottom surface (not shown) of the fuel cell module 3. Air can be supplied toward the bottom surface of the fuel cell module 3.
The terminals 11 are in contact with cathode current collectors 40 and anode current collectors 41 (after-mentioned, see
Top ends of the plungers (contacting portions of the cell holder) 110 are in contact with contact portions 401 (of the fuel cell module, see
The springs 112 and body portions 110a of the plungers 110 are inserted into the hollow insides of the barrels 111, respectively. Rear ends of the barrels 111 are electrically connected to the control substrate 12. The springs (contacting portion biasing means) 112 are compression coil springs inserted into the hollow insides of the barrels 111 to bias the plungers 110 toward the cathode current collectors 40 and anode current collectors 41. Accordingly, the terminals 11 can be in contact with the cathode current collectors 40 and anode current collectors 41 to electrically connect the fuel cell module 3 and the control substrate 12.
As shown in
The control substrate 12 is, for example, an electronic part for increasing or decreasing an output voltage of the fuel cell module 3. This control substrate 12 can control outputs of the power units 4 in accordance with a rated output of electronic equipment (not shown). The control substrate 12 is fixed inside the body 10. The terminals 1, the electric double layer capacitor 13, and the USB connector 14 are connected onto the control substrate 12. The control substrate 12 operates by power supply from the fuel cell module 3.
The electric double layer capacitor 13 is connected to the control substrate 12, and charged by electric power from the fuel cell module 3. For example, the electric double layer capacitor 13 is charged by predetermined electric power in advance. When an output of electric power of the fuel cell module 3 is unstable, such as when power generation begins, the electric double layer capacitor 13 can supply power to electronic equipment (not shown) preferentially, and can be charged by excess power. The electric double layer capacitor 13 is fixed inside the body 10.
The USB connector 14 is connected to the control substrate 12. Electric power from the fuel cell module 3 and electric double layer capacitor 13 is outputted from the USB connector 14 to electronic equipment (not shown) via a bus power line provided to a USB cable (not shown). The USB connector 14 is a receptacle.
Methanol aqueous solution (liquid fuel) which is a fuel for the fuel cell module 3 is stored in the fuel cartridge 15. The fuel cartridge 15 is detachably mounted on the body 10. The fuel cartridge 15 is filled with methanol aqueous solution having a concentration of methanol (fuel component) of, e.g., ten weight percent and with propellant gas. The methanol aqueous solution is supplied to the fuel cell module 3 via a tube 150.
The detachment preventing means 16 is mounted on the body 10 to prevent the detachment of the fuel cell module 3 mounted inside the body 10. As the detachment prevent means 16, triangular clasps are mounted on two corners facing each other in portions where the fuel cell module 3 is mounted on the body 10. The fuel cell module 3 is held between the detachment preventing means 16 and a bottom surface (not shown) of the body 10.
[Structure of the Fuel Cell Module]
The fuel cell module 3 generates electric power by use of oxygen in the air and methanol aqueous solution supplied from the fuel cartridge 15. As shown in
As shown in
The cathode current collectors 40 (40a, 40b) are plates provided adjacent air electrodes 420 of the MEAs 42. The anode current collectors 41 (41a, 41b) are plates provided adjacent fuel electrodes 421 of the MEAs 42. The cathode current collectors 40 and anode current collectors 41 are made of a conductive and corrosion-resistant material (for example, a metal such as titanium), and sandwich the MEAs 42. The cathode current collectors 40 and anode current collectors 41 are provided to derive electrical power efficiently in accordance with potential difference generated in the MEAs 42.
As shown in
Each of projecting portions 400 projects from a part of each the cathode current collectors 40 toward the side surface 31 of the case 6 (lower end plate 61). Each of projecting portions 410 projects from a part of each the anode current collectors 41 toward the side surface 31 of the case 6 (lower end plate 61). Top ends of the projecting portions 400 (400a, 400b), 410 (410a, 410b) are bended to have L-shaped cross sections so that the top ends are respectively in contact with the openings 62 (62d, 62b, 62c, 62a). The portions (contact portions 401, 411) facing the openings 62 of the projecting portions 400, 410 are open from the openings 62 to the outside of the case 6 along surfaces of the MEAs 42. The terminals 11 of the cell holder 1 can be mounted along the surfaces of the MEAs 42, along which surfaces the contact portions 401, 411 are open. Accordingly, the cell holder 1 can be thinned in comparison to the case where contact portions (not shown) are open in the thickness direction of the MEAs 42 and the terminals 11 are placed on the fuel cell module 3.
All the openings 62 are formed on one side surface 31, and the contact portions 401, 411 are open in the same direction. The contact portions 401, 411 are open in the same direction, so that the terminals 11 of the cell holder 1 can be arranged facing one side surface 31. The projecting portions 400, 410 are formed to have L-shapes. The contact portions 401, 411 are coincident in position with each other in the thickness direction of the MEAs 42 when viewed perpendicularly to the side surface 31. Accordingly, the terminals 11 of the cell holder 1 can be arranged in line horizontally.
The contact portions 401a, 411a in the plane view do not overlap with each other. The contact portions 401a, 411a are formed asymmetrically with respect to a symmetry axis A (see
Insulating portions 403, 413 (see
The MEAs 42 (42a, 42b) generate electrical power by use of air and methanol aqueous solution supplied from the flow holes 402 of the cathode current collectors 40 and the flow holes 412 of the anode current collectors 41. As shown in
The seal members 43 are positioned between edge portions of the electrolyte membranes 422 and the cathode current collectors 40 and between the edge portions of the electrolyte membranes 422 and the anode current collectors 41. The seal members 43 are formed of an elastic material (such as polytetrafluoro-ethylene and SBR). The seal members 43 are sandwiched between the electrolyte membranes 422 and cathode current collectors 40 and between the electrolyte membranes 422 and anode current collectors 41. The seal members 43 are elastically deformed to seal peripheries of the air electrodes 420 and fuel electrodes 421.
The seal members 43 may have adhesion layers (not shown) adhering to the members (the electrolyte membranes 422 and cathode current collectors 40, and the electrolyte membranes 422 and anode current collectors 41) in contact with surfaces of the seal members 43. Such adhesion layers make sealing ability of the seal members 43 higher.
The seal members 43 prevent, e.g., steam generated at the air electrodes 420 and methanol aqueous solution from flowing out of the MEAs 42. Since the outflow of, e.g., steam is prevented, the fuel cell module 3 can be contained in the cell holder 1 (see
Methanol aqueous solution from the fuel cartridge 15 (see
The fuel supply pipe 52 is a pipe for making methanol aqueous solution from the fuel cartridge 15 (see
The carbon dioxide discharging pipe 53 is a pipe for discharging carbon dioxide in the fuel flow path 51 to the outside. A top end of the carbon dioxide discharging pipe 53 projects outwardly from the case 6, and the other top end is connected to the fuel flow path 51. A carbon dioxide separation membrane (not shown) is provided to the fuel flow path 51. Carbon dioxide generated by power generation is separated from the methanol aqueous solution, and discharged from the carbon dioxide discharging pipe 53 to the outside.
The case 6 contains and protects the power units 4a, 4b and fuel tank 5 integrated with each other. As shown in
The openings 62 corresponding to the number of the cathode current collectors 40 and anode current collectors 41 are formed on the side surface 31 of the lower end plate 61. A plurality of the air flow holes 63 are formed on the top surface of the upper end plate 60 and the bottom surface of the lower end plate 61.
Not like conventional fuel cells, since the cell holder 1 and fuel cell module 3 are structured as described above, a conductive material does not need to be used to electrically connect the current collectors of a plurality of the power units 4 to each other in the fuel cell module 3. By mounting the fuel cell module 3 to the cell holder 1, the electrical connection between the cell holder 1 and fuel cell module 3 and the serial connection between the power units 4 in the fuel cell module 3 are achieved at the same time.
The anodes in the claims correspond to the anode current collectors 41 and fuel electrodes 421 in this embodiment. The cathodes in the claims correspond to the cathode current collectors 40 and air electrodes 420 in this embodiment.
[Mounting of the Fuel Cell Module to the Cell Holder]
The mounting of the fuel cell module 3 to the cell holder 1 is explained below in reference to
First, the terminals 11 of the cell holder 1 are aligned to the corresponding openings 62 of the fuel cell module 3. The fuel cell module 3 is pressed into the body 10 in the state where the plungers 110 of the terminals 11 are pressed into the barrels 111. At this time, the plungers 110 of the terminals 11 are biased by the springs 112 and inserted from the corresponding openings 62 into the fuel cell module 3. The plungers 110 are pressed against the contact portions 401 of the cathode current collectors 40 and the contact portions 411 of the anode current collectors 41 (see
The wiring (not shown) for electrically connecting the terminals 11a and 11b, and the wiring (not shown) for electrically connecting each of the terminals 11c,11d to the USB connector 14 are printed on the control substrate 12. Thus, the MEAs 42a, 42b (see
The tube 150 of the fuel cartridge 15 is mounted on the fuel supply pipe 52. The detachment preventing means 16 is mounted on the body 10 to fix the fuel cell module to the cell holder 1.
[Operation of the Cell Holder and Fuel Cell Module]
The operation of the cell holder I and fuel cell module 3 is explained below in reference to FIGS. 1 to 4.
Methanol aqueous solution is supplied from the fuel cartridge 15 to the fuel cell module 3 through the tube 150. This methanol aqueous solution flows from the fuel supply pipe 52 into the fuel flow path 51 of the fuel tank 5. Then, the methanol aqueous solution comes in contact with the fuel electrodes 421 (see
When methanol aqueous solution comes in contact with the fuel electrodes 421 and air (oxygen) comes in contact with the air electrodes 420, the USB connector 14 of the cell holder 1 is electrically connected to electronic equipment (load). At the fuel electrodes 421 and air electrodes 420 of the MEAs 42, methanol, water, and oxygen are electrochemically reacted as shown in the following equations (1) and (2). Then, power is generated.
Fuel electrodes 421: CH3OH+H2O→CO2+6H++6e− (1)
Air electrodes 420: O2+4H++4e−→2H2O (2)
Electricity is derived via the cathode current collectors 40 and anode current collectors 41, and supplied to the electronic equipment (not shown) via the USB connector 14 and a USB cable (not shown).
Carbon dioxide (CO2) generated at the fuel electrodes 421 becomes bubbles in methanol aqueous solution in the fuel flow path 51 of the fuel tank 5, and is discharged to the outside via a carbon dioxide separation membrane (not shown) and the carbon dioxide discharging pipe 53.
The preferred embodiments of the present invention have been explained above. The present invention is not limited to the above embodiments. Without departing from the scope of the invention, the following alternatives are possible.
For example, a wiring (cathode connecting portion, not shown) for electrically connecting the terminals 11a and 11d, and for connecting the terminals 11a, 11d to the USB connector 14, and a wiring (anode connecting portion, not shown) for electrically connecting the terminals 11b, 11c, and for connecting the terminals 11b, 11c to the USB connector 14 may be printed on the control substrate 12 of the cell holder. Accordingly, the MEAs 42a, 42b (see
As described above, all the openings 62 of the fuel cell module 3 are formed on the side surface 31, and the contact portions 401 of the cathode current collectors 40 and the contact portions 411 of the anode current collectors 41 are open in the same direction. Contact portions (not shown) of the fuel cell module 3 of the present invention may be open in the different directions along the surfaces of the MEAs 42. In this case, terminals (not shown) of the cell holder 1 are formed in positions corresponding to the contact portions.
The contact portions 401, 411 may be exposed to the outer surface of the side surface 31. In this case, the contact portions 401, 411 can be open along the surfaces of the MEAs 42, and the terminals 11 of the cell holder 1 can be placed along the surfaces of the MEAs 42.
When the power units 4 in the plane view have a square shape, a diagonal line (not shown) of the square may be the symmetry axis of the power units 4.
As described above, the case 6 covers the power units 4a, 4b and the fuel tank 5. The case 6 may enable a plurality of the power units 4 to be integrated with each other. For example, the case may be formed of a lower end plate (not shown) having a substantially U-shape in the side view and an upper end plate (not shown) mounted on an upper portion of the lower end plate, so that it is a case whose side facing the terminals 11 of the cell holder 1 is fully open.
The cell holder 1 of the present invention may supply electrical power of the fuel cell module 3 mounted inside the cell holder 1 to electronic equipment (not shown) via a USB cable (not shown) connected to the USB connector 14 (see
As described above, the terminals 11 of the cell holder 1 are spring probes. As shown in
As shown in
As shown in
Contact portions 401Ca, 411Ca do not overlap with each other in the plane view. The contact portions 401Ca, 411Ca are respectively formed asymmetrically with respect to the symmetry axis A of a plane shape of the power units 4 excluding the projecting portions 400C, 410C. Accordingly, the two power units 4a, 4b can have the same shape, and a simple production process can be achieved. Additionally, the two power units 4a, 4b are placed on both sides of the fuel tank 5 inversely with respect to the symmetry axis A. Accordingly, the contact portions 401C, 411C can be arranged not to overlap with each other in the plane view.
As described above, the case where the fuel cell module 3 includes the power units 4a, 4b between which the fuel tank 5 is sandwiched, has been explained. For example, as shown in
The power units 4Da, 4Db are placed laterally in parallel. Anode current collectors 41Da, 41Db, MEAs 42Da, 42Db, and cathode current collectors 40Da, 40Db are superimposed on the fuel tank 5 sequentially. A fuel flow path (not shown) is open from only the top surface of the tank 5. Projecting portions 400D of the cathode current collectors 40D and projecting portions 410D of the anode current collectors 41D are formed facing one side surface (not shown) of the case 6. Top ends of the projecting portions 400D, 410D are bended to have an L-shape for being in contact with an inner wall of this side surface. Openings (not shown) which are cylindrical holes are formed in portions of the lower end plate 61, the portions being in contact with the projecting portions 400D, 410D (contact portions 401, 411). All the contact portions 401, 411 are open from the openings to the outside in the direction perpendicular to this side surface. Terminals 11Dd, 11Db, 11Da, 11Dc of the cell holder (not shown) are pressed against contact portions 40Da, 401Db, 411Da, 411Db from the outside. A wiring (not shown) for electrically connecting the terminals 11D to each other and to the USB connector (not shown) in accordance with the above predetermined combination is printed on a control substrate (not shown). Accordingly, the MEAs 42Da, 42Db can be electrically connected to each other in series or in parallel.
In the fuel cell modules 3 shown in
As described above, the anode current collectors 41 are provided adjacent the fuel electrodes 421, the cathode current collectors 40 are provided adjacent the air electrodes 420, and the contact portions 401, 411 are respectively provided to the cathode current collectors 40 and anode current collectors 41. In the fuel cell module of the present invention, an anode and a cathode (not shown) formed of a porous material holding a catalyst having sufficient conductivity, corrosion resistance, and strength, such as platinum, are respectively provided to both surfaces of an electrolyte membrane (not shown) to form an MEA (not shown). Contact portions may be provided to the anode and cathode.
Number | Date | Country | Kind |
---|---|---|---|
2005-245798 | Aug 2005 | JP | national |