JP4672232B2 - Fuel cell device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell device that is mainly composed of a direct methanol fuel cell and is suitable for incorporation as a power source for a small electronic device.
[0002]
[Related background]
A direct methanol fuel cell generates electricity by chemically reacting an aqueous methanol solution and air at about room temperature via an electrolyte membrane, eliminating the need for a reformer as found in phosphoric acid electrolyte fuel cells. And its structure is relatively simple. In particular, direct methanol fuel cells are expected to be applied to portable or portable electronic devices as power supply equipment to replace conventional secondary batteries or primary batteries because of their small fuel volume and easy miniaturization. .
[0003]
[Problems to be solved by the invention]
By the way, in order to use this type of fuel cell device as a power source for small electronic devices, a direct type methanol fuel cell (DMFC) that is a main part of the fuel cell device is filled with a methanol aqueous solution as a fuel, or a methanol aqueous solution is used as a DMFC. It is conceivable to integrate a liquid feed pump to be supplied and pack it as one power supply unit.
[0004]
However, since the output voltage of the fuel cell device is maintained at a constant value, it is difficult to determine the usable battery capacity (remaining amount) from the decrease in the output voltage, like a secondary battery or a primary battery. is there. Further, in the case of a packed fuel cell device, for example, a configuration that facilitates replacement of the fuel cartridge is employed. In this case, the power generation possible time in the direct methanol fuel cell changes depending on the type of the fuel cartridge and the remaining amount of the methanol aqueous solution (fuel) filled. For example, when the fuel runs out, the small electronic device is driven. There is also concern that will be suddenly interrupted.
[0005]
Further, in order to drive auxiliary equipment such as a liquid feed pump incorporated in a packed fuel cell device, a power source is required. It is conceivable to use power generated by the fuel cell device as the power source. However, the fuel cell itself has a problem that the output voltage is zero when the fuel cell is started, and therefore the fuel cell device cannot be started only by the fuel cell. Furthermore, the output voltage of the fuel cell device is unstable at the initial stage of power generation, and the voltage becomes unstable due to a time lag until the fuel cell output follows the load when the load suddenly changes. Another problem is that when the load demands electric power exceeding the allowable maximum output of the fuel cell device, the output voltage of the fuel cell device decreases and the operation becomes unstable.
[0006]
In particular, the load power required by an electronic device equipped with a microcomputer or the like changes every moment and sometimes becomes a large value instantaneously. In order to drive such a load that takes instantaneous maximum power, it is necessary to always generate power in accordance with the instantaneous maximum power of the output power of the fuel cell device. For this reason, in a state other than the instantaneous maximum power of the load, fuel methanol and oxidant oxygen are excessively supplied to the fuel cell device. That is, there is a problem that the fuel consumption of the fuel cell device increases and it is not suitable as a power source for small portable devices.
[0007]
The present invention has been made in view of such circumstances, and an object of the present invention is to reliably monitor the operation state including the power generation possible time of the fuel cell device on the electronic device side using the fuel cell device. Another object of the present invention is to provide a fuel cell device suitable as a power source for a small electronic device capable of performing a stable power generation operation for the fuel cell device.
[0008]
[Means for Solving the Problems]
In order to achieve the above-described object, a fuel cell device according to the present invention includes a direct methanol fuel cell unit that generates electric power by chemically reacting methanol fuel and air via an electrolyte membrane, and the direct methanol fuel cell. A fuel cartridge containing methanol fuel to be supplied to the unit, and is a fuel cell device used by being mounted on an electronic device that operates using the electric power generated by the direct methanol fuel cell unit as a power source,
In particular, for the electronic device, the remaining amount of methanol fuel in the fuel cartridge and / or a detection unit provided in the direct methanol fuel cell unit is detected and used for power generation control of the direct methanol fuel cell unit. From information, for example, the output voltage of the direct methanol fuel cell unit, the terminal voltage of the secondary battery device, the supply voltage to the electronic device, the supply current to the electronic device, and the temperature of the direct methanol fuel cell unit Communication means for notifying at least one selected as the operating state of the direct methanol fuel cell unit;
Furthermore, a secondary battery device as an auxiliary power source for assisting the power generation operation of the direct methanol fuel cell unit is provided.
[0009]
According to the present invention, even if there is a temporary increase in load power exceeding the rated output of the fuel cell device, the secondary battery device compensates for the power shortage of the direct methanol fuel cell unit, so There is no adverse effect such as interruption or voltage drop.
[0010]
In the communication means, it is preferable that the remaining battery level of the secondary battery device is further notified to an electronic device using the fuel cell device . That is, by notifying the electronic equipment of various information detected by the detection unit provided in the fuel cell device , the remaining amount of methanol fuel supplied in the fuel cartridge, etc. It is characterized by being able to manage .
[0011]
The first backflow prevention diode interposed between the direct methanol fuel cell unit and the electronic device, and the secondary battery device (auxiliary power source) and the electronic device. And a second backflow prevention diode, and an output circuit that combines the power output through the first and second backflow prevention diodes and supplies the combined power to the electronic device.
[0012]
That is, this output circuit constitutes an OR circuit by the diode, and when the direct methanol fuel cell unit is in a steady operation, power is supplied from the direct methanol fuel cell unit to the load, and the load power increases. When the power supply is insufficient, the secondary battery device can compensate the power shortage and supply it to the load.
[0013]
Preferably, the direct methanol fuel cell unit has an output voltage higher than that of the secondary battery device during steady power generation.
More preferably, the secondary battery device has a lower output impedance than the output impedance of the methanol fuel cell in order to continuously supply power without causing a momentary interruption or the like with respect to a sudden change in load power. It is desirable.
[0014]
Further, by providing a display unit for displaying the remaining amount of methanol in the fuel cartridge, it is possible to prompt the user to replenish the fuel or replace the fuel cartridge when the remaining amount of methanol decreases.
Preferably, the display unit displays when the remaining amount of the fuel cartridge falls below a predetermined amount.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a fuel cell device according to an embodiment of the present invention will be described with reference to the drawings.
[0016]
FIG. 1 is a block diagram showing a schematic configuration of a fuel cell device according to the present invention. The fuel cell device 10 mainly includes a DMFC electromotive device 100 that generates an electromotive force through a chemical reaction between a methanol aqueous solution of fuel and air (O ₂ ) through an electrolyte membrane. A liquid feed pump 41 for supplying an aqueous methanol solution and an air feed pump 42 for supplying air (O ₂ ) as an oxidant are integrally incorporated. The fuel cell device 10 includes a DMFC control unit (power generation control unit) 20 that controls the operation of the pumps 41 and 42 to control the power generation operation of the DMFC electromotive device 100, and a secondary battery, for example. The auxiliary power supply unit 60 is integrated into a single power supply unit.
[0017]
Furthermore, the fuel cell device 10 includes an auxiliary power supply unit 60 that drives the pumps 41 and 42 when the DMFC electromotive device 100 is started. This auxiliary power supply unit 60 is composed of, for example, a secondary battery device, and when the voltage due to a time lag until the fuel cell output follows the load is unstable before the DMFC electromotive device 100 undergoes an electromotive reaction and when the load suddenly changes. Instead of the DMFC electromotive device 100, it also plays a role of supplying power to the DMFC control unit (power generation control unit) 20 and the like.
[0018]
Incidentally, an aqueous methanol solution as a fuel is filled in a fuel cartridge 30 that is detachably attached to the fuel cell device 10. By attaching the fuel cartridge 30 to the fuel cell device 10, an aqueous methanol solution is supplied to the DMFC electromotive device 100 via the liquid feed pump 41. Air (O ₂ ) as an oxidant is supplied to the DMFC electromotive device 100 by taking in the ambient air around the air pump 42.
[0019]
Here, the DMFC electromotive device 100 will be briefly described. As schematically shown in FIG. 2, the DMFC electromotive device 100 includes an anode flow channel body 121 having a flow channel 120 through which an aqueous methanol solution flows with an electrolyte membrane 110 interposed therebetween, and air. A structure is provided in which a cathode channel body 131 having a channel 130 to flow therethrough is provided. In particular, an anode catalyst layer 122 and a cathode catalyst layer 132 are provided on both surfaces of the electrolyte membrane 110, respectively, and an anode current collector 123 and a cathode current collector 133 are provided on the outer sides thereof.
[0020]
In the DMFC electromotive device 100 having such a structure, basically, the aqueous methanol solution fed into the anode flow passage 121 soaks into the anode catalyst layer 122 through the anode current collector 123. Further, the air (O ₂ as an oxidant) sent into the cathode flow path body 131 soaks into the cathode catalyst layer 132 through the cathode current collector 133. Then, the methanol aqueous solution undergoes a chemical reaction under the catalytic action of the anode catalyst layer 122, and protons (protons) generated thereby pass through the electrolyte membrane 110. Then, the oxygen impregnated in the cathode catalyst layer 132 and the protons react to generate electric power (generate electric power). The electromotive force accompanying such a chemical reaction is taken out through the anode current collector 123 and the cathode current collector 133, respectively.
[0021]
Basically, in the fuel cell device 10 configured as described above, the present invention is characterized in that the fuel cell device 10 is used as a power source as shown in FIG. 1, for example, a portable or portable electronic device. The communication device 80 is provided for notifying the device 200 of information such as the remaining amount of the fuel cartridge 30 and the operating state of the DMFC electromotive device 100.
[0022]
The fuel cell device 10 provided with such communication means 80 will be described in more detail with reference to the control circuit block diagram shown in FIG.
The power generation control unit 20 includes a DMFC voltage detection unit 70a that monitors a voltage output from the DMFC electromotive device 100, a secondary battery voltage detection unit 70b that monitors a terminal voltage of the auxiliary power supply unit (secondary battery) 60, An output voltage detector 70c that monitors the voltage supplied from the fuel cell device 10 to the load, and a current detector 71 that detects the load current are provided. The power generation control unit 20 includes a temperature detection unit 72 that detects the temperature of the DMFC electromotive device 100 and a remaining amount detection unit 31 that detects the remaining amount of fuel in the fuel cartridge 30. And the electric power generation control part 20 is controlled so that it may become an optimal pump flow volume based on the information each obtained from each of these detection parts.
[0023]
That is, the methanol filled in the fuel cartridge 30 and the air (O ₂ ) as the oxidant are respectively sent to the DMFC electromotive device 100 by the liquid feed pump 41 and the air feed pump 42 as described above. And these pumps 41 and 42 are drive-controlled based on the information obtained from the various detection parts 70 mentioned above so that it may become an optimal pump flow volume under control of DMFC control part (power generation control part) 20. .
[0024]
On the other hand, the remaining amount of the methanol aqueous solution filled in the fuel cartridge 30 is monitored by the remaining amount detection unit 31. The remaining amount of the methanol aqueous solution is given to the communication means 80 from the DMFC control unit (power generation control unit) 20 together with the information of the various detection units 70 described above, and a portable or portable electronic device using the fuel cell device 10 is provided. The device 200 is notified at predetermined intervals. Further, in addition to the information described above, the electronic device 200 may be notified including information such as operation control states of various pumps of the fuel cell device 10 and, as will be described later, charge / discharge states of the secondary battery.
[0025]
Information to be notified to the electronic device 200 includes, for example, the maker name, cartridge name, date of manufacture, cartridge maximum capacity, fuel concentration, fuel type, maximum number of insertions / removals, and maximum liquid supply for the fuel cartridge 30. It consists of information such as quantity, minimum operating temperature, and maximum operating temperature. Furthermore, information such as the remaining capacity of the fuel, the number of insertions / removals thereof, the usage elapsed time, and an abnormality flag may be notified in accordance with the usage status (consumption status) of the aqueous methanol solution filled in the fuel cartridge 30.
[0026]
By notifying such information, for example, the DMFC control unit 20 can take measures such as prohibiting the use of the fuel cartridge 30 after a predetermined period of time, and the fuel cartridge 30 that is about to run out of fuel can be taken. It is possible to take measures such as prompting replacement. Further, by using the remaining capacity data in the fuel cartridge 30, the DMFC control unit 20 can calculate the remaining fuel ratio and the like.
[0027]
In addition to the information regarding the fuel cartridge 30, if the electronic device 200 is notified of the operating state of the DMFC electromotive device 100 and further the operating state of the auxiliary power supply unit (secondary battery) 60, the fuel in the electronic device 200 It becomes possible to accurately grasp the operating state of the battery device 10. For this reason, in the electronic device 200, an appropriate measure can be taken before the function of the fuel cell device 10 deteriorates. Furthermore, the above information can be utilized for maintenance of the fuel cell device 10, for example, and the fuel cell device 10 can be effectively operated.
[0028]
The communication unit 80 is not particularly illustrated, but may be any unit that communicates information with the electronic device 200 by terminal coupling, or information communication by radio wave, electromagnetic coupling, optical coupling, or the like. There may be.
[0029]
Incidentally, the DMFC control unit (power generation control unit) 20 is basically configured to operate using the DMFC electromotive device 100 as a power source. However, the electromotive force of the DMFC electromotive device 100 is zero before the electromotive reaction, and the output voltage of the DMFC electromotive device 100 is unstable at the initial power generation. Moreover, when the load suddenly changes, there is a time lag until the output power of the fuel cell device follows the load, and the output voltage becomes unstable.
[0030]
For this reason, the auxiliary power supply unit 60 described above is provided on the output side of the DMFC electromotive device 100. When the auxiliary power supply unit 60 or the DMFC electromotive device 100 described above is in the initial stage of power generation or when its operation is unstable, power is supplied to the DMFC control unit (power generation control unit) 20 or the like instead of the DMFC electromotive device 100. Has a role to supply.
Further, when a direct methanol fuel cell device is applied as a power source for a small portable terminal, the auxiliary power supply unit 60 compensates for the voltage instability phenomenon described above and also serves to stabilize the output voltage of the fuel cell device 10. Yes.
[0031]
The auxiliary power supply unit 60 is configured using a primary battery or a secondary battery. In particular, with a configuration using a secondary battery, when the power generation output voltage of the DMFC electromotive device 100 becomes surplus, the surplus power can be used to charge the secondary battery, and the DMFC A secondary battery can be used as a power source when starting up the electric device 100, and more efficient operation can be performed. Furthermore, by connecting the secondary battery in parallel with the output of the DMFC electromotive device 100 through a diode, it is possible to compensate for the voltage instability phenomenon of the DMFC electromotive device 100 at the initial stage of power generation and sudden load change. Become.
[0032]
In addition, charge / discharge control of the secondary battery is performed by the secondary battery control unit 61. Therefore, it is desirable that the electronic device 200 is notified of the operation state of the secondary battery control unit 61, specifically, the charge / discharge state of the secondary battery using the communication unit 80 described above. .
[0033]
In addition, a display unit (for example, showing the remaining amount of aqueous methanol solution filled in the fuel cartridge 30 even when the fuel cell device 10 is removed from an electronic device or the like in which the fuel cell device 10 is incorporated, for example) (Not shown) is preferably provided in the fuel cell device 10. This display unit changes its lighting state when, for example, a remaining amount indicator using a small liquid crystal display (LCD) or the like, or when the remaining amount of aqueous methanol solution filled in the fuel cartridge 30 falls below a predetermined amount. What is necessary is just to make it the structure by the light emitting diode (LED) etc. to be made.
[0034]
Thus, according to the fuel cell device 10 configured as described above, the remaining amount of the methanol aqueous solution filled in the fuel cartridge 30 and the operating state of the DMFC electromotive device 100 are portable or portable using the communication means 80. Since the electronic device 200 is notified, the state of the fuel cell device 10 can be accurately grasped on the electronic device 200 side. Further, it is possible to easily calculate the power generation possible time in the fuel cell device 10 based on the notified information, and it can be used for maintenance of the fuel cell device 10 and the like.
[0035]
Furthermore, according to this embodiment of the present invention, the auxiliary power supply unit 60 that assists the power generation operation of the DMFC electromotive device 100 is provided, so that the voltage non- A stable phenomenon can be eliminated.
[0036]
In addition, since a display unit that can display the remaining amount of the methanol aqueous solution filled even when the fuel cell device 10 is in a single state is provided, it is possible to reliably refill the fuel or replace the fuel cartridge 30 as necessary. It can be carried out.
[0037]
The present invention is not limited to the embodiment described above. For example, here, a fuel cartridge 30 having a structure in which the fuel cartridge 30 is provided detachably with respect to the fuel cell device 10 is illustrated, but a fuel tank (not shown) capable of storing a predetermined amount of aqueous methanol solution is integrally provided. The present invention can be similarly applied to a fuel cell device configured to be able to supply a methanol aqueous solution from the outside to the tank. Further, here, the methanol aqueous solution is supplied to the DMFC electromotive device 100 using the liquid feed pump 41, but for a so-called breathing type fuel cell device that does not use the liquid feed pump 41 or the air feed pump 42. Is equally applicable. In short, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
[0038]
【The invention's effect】
As described above, according to the fuel cell device of the present invention, the remaining amount of the methanol aqueous solution filled in the fuel cartridge and the operating state of the direct methanol cell are notified to the electronic device using this fuel cell device. Since the communication means is provided, the operation state of the fuel cell device can be simplified and accurately grasped on the electronic device side. In particular, by utilizing a microprocessor or the like incorporated in an electronic device, it is possible to calculate the power generation possible time of the fuel cell device, and it is possible to easily collect the operation history, etc. Played.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a direct methanol fuel cell according to an embodiment of the present invention.
FIG. 2 is a diagram schematically showing a schematic configuration of a direct methanol fuel cell.
FIG. 3 is a block diagram showing a control configuration of a direct methanol fuel cell according to an embodiment of the present invention.
[Explanation of symbols]
10 Fuel Cell Device 20 DMFC Control Unit (Power Generation Control Unit)
30 Fuel Cartridge 41 Liquid Supply Pump 42 Air Supply Pump 60 Auxiliary Power Supply Unit (Secondary Battery)
80 Communication means 100 DMFC electromotive device 200 Electronic equipment

Claims (11)

A direct methanol fuel cell unit that generates electric power by chemically reacting methanol fuel and air through an electrolyte membrane;
A fuel cartridge containing methanol fuel to be supplied to the direct methanol fuel cell unit;
A fuel cell device used by being mounted on an electronic device that operates using power generated by the direct methanol fuel cell unit as a power source,
The electronic device is detected by at least a remaining amount of methanol fuel in the fuel cartridge and / or a detection unit provided in the direct methanol fuel cell unit, and is used for power generation control of the direct methanol fuel cell unit. Communication means for notifying information as an operating state of the direct methanol fuel cell unit;
And a secondary battery device as an auxiliary power source for assisting the power generation operation of the direct methanol fuel cell unit. The fuel cell device according to claim 1,
  Information detected by the detection unit and used for power generation control includes an output voltage of the direct methanol fuel cell unit, a terminal voltage of the secondary battery device, a supply voltage to the electronic device, and a supply current to the electronic device. And at least one selected from the temperature of the direct methanol fuel cell section. The fuel cell device according to claim 1,
A fuel cell device comprising a liquid feed pump for supplying methanol fuel stored in the fuel cartridge to the direct methanol fuel cell unit. The fuel cell device according to claim 1,
A fuel cell device comprising an air supply pump for supplying air to the direct methanol fuel cell unit. The fuel cell device according to claim 3 or 4 ,
A fuel cell apparatus comprising: a power generation control unit that controls operation of each pump to control power generation by the direct methanol fuel cell unit. The fuel cell device according to claim 1,
The said communication means is a fuel cell apparatus which notifies the battery remaining amount of the said secondary battery apparatus with respect to the said electronic device further. A fuel cell device used by being mounted on an electronic device that operates using power generated by the direct methanol fuel cell unit as a power source,
A first backflow prevention diode interposed between the direct methanol fuel cell unit and the electronic device;
A second backflow prevention diode interposed between the secondary battery device and the electronic device;
2. The fuel cell device according to claim 1, further comprising an output circuit that synthesizes electric power output through the first and second backflow prevention diodes and supplies the combined electric power to the electronic device. The fuel cell device according to claim 7 , wherein the direct methanol fuel cell unit has an output voltage higher than that of the secondary battery device during steady power generation. The fuel cell device according to claim 8 , wherein the secondary battery device has an output impedance lower than that of the methanol fuel cell. The fuel cell device according to any one of claims 1 to 9 ,
The fuel cell apparatus further comprises a display unit for displaying the remaining amount of methanol fuel in the fuel cartridge. The fuel cell device according to claim 10 , wherein the display unit displays when the remaining amount of the fuel cartridge falls below a predetermined amount.

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