JP2010033904A - Fuel cell system and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an economically advantageous fuel cell system for improving specific fuel consumption, and to provide electronic equipment. <P>SOLUTION: Output voltage VB is detected which is equivalent to the charging voltage of an auxiliary power supply 4 to which the generating output of a fuel cell body 1 is supplied. When the output voltage VB is an upper limit value VBL or smaller and an intermediate value VBM or greater, a fuel priority mode is shifted in consideration of specific fuel consumption. When the output voltage VB is the upper limit value VBL or smaller and the intermediate value VBM or smaller, an output priority mode is shifted in consideration of output priority. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell system and an electronic apparatus using the fuel cell system as a power source.

  There have been remarkable miniaturizations of electronic devices such as mobile phones and portable information terminals, and along with the miniaturization of these electronic devices, attempts have been made to use fuel cells as a power source. A fuel cell has the advantage that it can generate electricity only by supplying fuel and air, and can generate electricity continuously by replacing only the fuel. Therefore, if it can be downsized, it can be used as a power source for small electronic devices. It is valid.

  Therefore, a direct methanol fuel cell (hereinafter, referred to as DMFC; Direct Methanol Fuel Cell) has attracted attention as a fuel cell. Such DMFCs are classified according to the liquid fuel supply system, such as an active system such as a gas supply type and a liquid supply type, and an internal vaporization type that vaporizes the liquid fuel in the fuel storage section inside the battery and supplies it to the fuel electrode. Among these, the passive type is particularly advantageous for reducing the size of the DMFC.

  Conventionally, as such a passive DMFC, as disclosed in Patent Document 1, for example, a membrane electrode assembly (fuel cell) having a fuel electrode, an electrolyte membrane, and an air electrode is removed from a resin box-like container. The thing of the structure arrange | positioned on the fuel accommodating part which becomes is considered.

Patent Documents 2 to 4 also disclose a configuration in which a DMFC fuel cell and a fuel storage unit are connected via a flow path. In these Patent Documents 2 to 4, by supplying the liquid fuel supplied from the fuel storage portion to the fuel cell via the flow path, the supply amount of the liquid fuel can be adjusted based on the shape and diameter of the flow path. In particular, in Patent Document 3, liquid fuel is supplied from the fuel storage portion to the flow path by a pump. Further, it is described that an electric field forming means for forming an electroosmotic flow in the flow path is used instead of the pump. Furthermore, Patent Document 4 describes that liquid fuel or the like is supplied using an electroosmotic pump.
International Publication No. 2005/112172 Pamphlet JP 2005-518646 A JP 2006-089552 A US Patent Publication No. 2006/0029851 JP 2005-32603 A

  By the way, when such a fuel cell system using the DMFC as a main power generation unit is applied as a power source for a small electronic device or the like, it is important that the fuel consumption in the fuel cell is small and economically advantageous.

  In view of this, conventionally, as disclosed in Patent Document 5, it has been considered that the operation mode of the fuel cell is switched between the energy saving mode and the high output mode in accordance with the use state of the electric device. However, in Patent Document 5, since the output of the fuel cell is compared with the power consumption during the operation of the electric device and the mode is switched according to the usage rate, the fuel is affected by the influence of the ambient temperature, for example. If the output of the battery may decrease, the power consumption during operation of the electrical equipment will be small, but the usage rate will exceed the predetermined ratio and switch to the high output mode, during which fuel will be wasted. There was a problem. In addition, since the output of the fuel cell and the measurement of the power consumption during the operation of the electric device are simultaneously performed, the circuit configuration becomes complicated, and the mode is switched by controlling the concentration of the circulating fuel. Therefore, there is a problem that the control system for supplying fuel becomes complicated.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an economically advantageous fuel cell system and electronic device that can improve the fuel consumption rate.

  The invention according to claim 1 is a fuel cell main body that generates power by supplying fuel, an auxiliary power source that is charged by a power generation output of the fuel cell main body, and that is used as a power source of an electronic device main body, and an output of the auxiliary power source Output detection means for detecting fuel consumption, operation mode selection means for selecting a fuel efficiency priority mode considering fuel efficiency priority or an output priority mode considering output priority based on the output detected by the output detection means, and the operation mode selection And control means for controlling the output of the fuel cell main body in accordance with the priority mode selected by the means.

  According to a second aspect of the present invention, in the first aspect, the operation mode selection unit selects the fuel efficiency priority mode when the output of the auxiliary power detected by the output detection unit is equal to or less than an upper limit value and equal to or greater than a predetermined value. The output priority mode is selected when the output is less than or equal to the predetermined value.

  According to a third aspect of the present invention, in the first or second aspect, the control means outputs the output of the fuel cell main body according to the fuel consumption priority mode or the output priority mode as a control voltage and a control temperature of the fuel cell main body. It is characterized by being obtained by controlling at least one of them.

  According to a fourth aspect of the present invention, there is provided an electronic device using the fuel cell system according to any one of the first to third aspects as a power source.

  ADVANTAGE OF THE INVENTION According to this invention, a fuel consumption rate can be improved and the fuel cell system and electronic device which are economically advantageous can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows a schematic configuration of a fuel cell system according to a first embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes a fuel cell main body (DMFC). The fuel cell main body 1 includes a fuel cell power generation unit (cell) 101 that constitutes an electromotive unit, a fuel storage unit 102 that stores liquid fuel, and a fuel storage unit 102. And a flow path 103 connecting the fuel cell power generation unit (cell) 101 and a pump 104 as a fuel supply control means for transferring liquid fuel from the fuel storage unit 102 to the fuel cell power generation unit (cell) 101. .

  FIG. 2 is a cross-sectional view for explaining the fuel cell main body 1 in more detail.

  In this case, the fuel cell power generation unit 101 includes an anode (fuel electrode) 13 having an anode catalyst layer 11 and an anode gas diffusion layer 12, and a cathode (air electrode / oxidation) having a cathode catalyst layer 14 and a cathode gas diffusion layer 15. The electrode assembly 16 has a membrane electrode assembly (MEA) composed of a proton (hydrogen ion) conductive electrolyte membrane 17 sandwiched between the anode catalyst layer 11 and the cathode catalyst layer 14. ing.

  Here, examples of the catalyst contained in the anode catalyst layer 11 and the cathode catalyst layer 14 include a simple substance of a platinum group element such as Pt, Ru, Rh, Ir, Os, and Pd, an alloy containing the platinum group element, and the like. It is done. For the anode catalyst layer 11, it is preferable to use Pt—Ru, Pt—Mo, or the like having strong resistance to methanol, carbon monoxide, or the like. Pt, Pt—Ni or the like is preferably used for the cathode catalyst layer 14. However, the catalyst is not limited to these, and various substances having catalytic activity can be used. The catalyst may be either a supported catalyst using a conductive support such as a carbon material or an unsupported catalyst.

  Examples of the proton conductive material constituting the electrolyte membrane 17 include fluorine-based resins (Nafion (trade name, manufactured by DuPont) and Flemion (trade name, manufactured by Asahi Glass Co., Ltd.) such as a perfluorosulfonic acid polymer having a sulfonic acid group. Etc.), organic materials such as hydrocarbon resins having sulfonic acid groups, or inorganic materials such as tungstic acid and phosphotungstic acid. However, the proton conductive electrolyte membrane 17 is not limited to these.

  The anode gas diffusion layer 12 laminated on the anode catalyst layer 11 serves to uniformly supply fuel to the anode catalyst layer 11 and also serves as a current collector for the anode catalyst layer 11. The cathode gas diffusion layer 15 laminated on the cathode catalyst layer 14 serves to uniformly supply the oxidant to the cathode catalyst layer 14 and also serves as a current collector for the cathode catalyst layer 14. The anode gas diffusion layer 12 and the cathode gas diffusion layer 15 are made of a porous substrate.

  A conductive layer is laminated on the anode gas diffusion layer 12 and the cathode gas diffusion layer 15 as necessary. As these conductive layers, for example, a porous layer (for example, mesh) made of a conductive metal material such as Au or Ni, a porous film, a foil body, a conductive metal material such as stainless steel (SUS), gold or the like. A composite material coated with a highly conductive metal is used. Rubber O-rings 19 are interposed between the electrolyte membrane 17 and a fuel distribution mechanism 105 and a cover plate 18, which will be described later, thereby preventing fuel leakage and oxidant leakage from the fuel cell power generation unit 101. is doing.

  The cover plate 18 has an opening (not shown) for taking in air as an oxidant. A moisture retaining layer and a surface layer are disposed between the cover plate 18 and the cathode 16 as necessary. The moisturizing layer is impregnated with a part of the water generated in the cathode catalyst layer 14 to suppress the transpiration of water and promote uniform diffusion of air to the cathode catalyst layer 14. The surface layer adjusts the amount of air taken in, and has a plurality of air inlets whose number, size, etc. are adjusted according to the amount of air taken in.

  A fuel distribution mechanism 105 is disposed on the anode (fuel electrode) 13 side of the fuel cell power generation unit 101. A fuel storage unit 102 is connected to the fuel distribution mechanism 105 via a liquid fuel flow path 103 such as a pipe.

  Liquid fuel corresponding to the fuel cell power generation unit 101 is stored in the fuel storage unit 102. Examples of the liquid fuel include methanol fuels such as aqueous methanol solutions of various concentrations and pure methanol. The liquid fuel is not necessarily limited to methanol fuel. The liquid fuel may be, for example, an ethanol fuel such as an ethanol aqueous solution or pure ethanol, a propanol fuel such as a propanol aqueous solution or pure propanol, a glycol fuel such as a glycol aqueous solution or pure glycol, dimethyl ether, formic acid, or other liquid fuel. In any case, liquid fuel corresponding to the fuel cell power generation unit 101 is stored in the fuel storage unit 102.

  Fuel is introduced into the fuel distribution mechanism 105 from the fuel storage portion 102 via the flow path 103. The flow path 103 is not limited to piping independent of the fuel distribution mechanism 105 and the fuel storage unit 102. For example, when the fuel distribution mechanism 105 and the fuel storage unit 102 are stacked and integrated, a fuel flow path connecting them may be used. The fuel distribution mechanism 105 only needs to be connected to the fuel storage unit 102 via the flow path 103.

  Here, as shown in FIG. 3, the fuel distribution mechanism 105 includes at least one fuel inlet 21 through which fuel flows through the flow path 103 and a plurality of fuel outlets 22 through which fuel and its vaporized components are discharged. The fuel distribution plate 23 having As shown in FIG. 2, a gap 24 serving as a fuel passage led from the fuel inlet 21 is provided inside the fuel distribution plate 23. The plurality of fuel discharge ports 22 are directly connected to gaps 24 that function as fuel passages.

  The fuel introduced into the fuel distribution mechanism 105 from the fuel inlet 21 enters the gap portion 24 and is guided to the plurality of fuel discharge ports 22 through the gap portion 24 functioning as the fuel passage. For example, a gas-liquid separator (not shown) that transmits only the vaporized component of the fuel and does not transmit the liquid component may be disposed in the plurality of fuel discharge ports 22. As a result, the fuel vaporization component is supplied to the anode (fuel electrode) 13 of the fuel cell power generation unit 101. The gas-liquid separator may be installed as a gas-liquid separation membrane or the like between the fuel distribution mechanism 105 and the anode 13. The vaporized component of the fuel is discharged from a plurality of fuel discharge ports 22 toward a plurality of locations on the anode 13.

A plurality of fuel discharge ports 22 are provided on the surface of the fuel distribution plate 23 in contact with the anode 13 so that fuel can be supplied to the entire fuel cell power generation unit 101. The number of the fuel discharge ports 22 may be two or more. However, in order to equalize the fuel supply amount in the plane of the fuel cell power generation unit 101, the fuel discharge ports 22 of 0.1 to 10 / cm ² are provided. It is preferable to form it so that it exists.

  A pump 104 serving as a fuel transfer control unit is inserted into a flow path 103 that connects between the fuel distribution mechanism 105 and the fuel storage unit 102. The pump 104 is not a circulation pump through which fuel is circulated, but is a fuel supply pump that transfers fuel from the fuel storage unit 102 to the fuel distribution mechanism 105 to the last. By supplying the fuel when necessary with such a pump 104, the controllability of the fuel supply amount is improved. In this case, a rotary vane pump, an electroosmotic pump, a diaphragm pump, a squeezing pump, etc. should be used as the pump 104 from the viewpoint that a small amount of fuel can be sent with good controllability and can be reduced in size and weight. Is preferred. A rotary vane pump feeds liquid by rotating a wing with a motor. The electroosmotic flow pump uses a sintered porous material such as silica that causes an electroosmotic flow phenomenon. The diaphragm pump is a pump that feeds liquid by driving the diaphragm with an electromagnet or piezoelectric ceramics. The squeezing pump presses a part of the flexible fuel flow path and squeezes the fuel. Among these, it is more preferable to use an electroosmotic pump or a diaphragm pump having piezoelectric ceramics from the viewpoint of driving power, size, and the like.

  In addition, a fuel supply control circuit 5 described later is connected to the pump 104, and the drive of the pump 104 is controlled. This point will be described later.

  In such a configuration, the fuel stored in the fuel storage unit 102 is transferred through the flow path 103 by the pump 104 and supplied to the fuel distribution mechanism 105. The fuel released from the fuel distribution mechanism 105 is supplied to the anode (fuel electrode) 13 of the fuel cell power generation unit 101. In the fuel cell power generation unit 101, the fuel diffuses through the anode gas diffusion layer 12 and is supplied to the anode catalyst layer 11. When methanol fuel is used as the fuel, an internal reforming reaction of methanol shown in the following formula (1) occurs in the anode catalyst layer 11. When pure methanol is used as the methanol fuel, the water generated in the cathode catalyst layer 14 or the water in the electrolyte membrane 17 is reacted with methanol to cause the internal reforming reaction of the formula (1). Alternatively, the internal reforming reaction is caused by another reaction mechanism that does not require water.

CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻ (1)
Electrons (e ⁻ ) generated by this reaction are guided to the outside via a current collector, supplied to the load side as so-called output, and then guided to the cathode (air electrode) 16. Further, protons (H ⁺ ) generated by the internal reforming reaction of the formula (1) are guided to the cathode 16 through the electrolyte membrane 17. Air is supplied to the cathode 16 as an oxidant. Electrons (e ⁻ ) and protons (H ⁺ ) that have reached the cathode 16 react with oxygen in the air according to the following equation (2) in the cathode catalyst layer 14, and water is generated with this reaction.

6e ⁻ + 6H ⁺ + (3/2) O ₂ → 3H ₂ O (2)
Returning to FIG. 1, in the fuel cell main body 1 configured in this way, the fuel cell power generation unit (cell) 101 is provided with a temperature sensor 106 as second temperature detection means. The temperature sensor 106 detects the temperature of the heat generating part of the fuel cell power generation unit (cell) 101, and is composed of, for example, a thermistor or a thermocouple, and is the cathode (air) of the fuel cell power generation unit (cell) 101 shown in FIG. Pole) 16. Further, the temperature sensor 106 outputs a detection signal corresponding to the heat generation temperature to the control unit 7. The controller 7 will be described later.

  The fuel cell body 1 is connected to an output detection unit 6 and a DC-DC converter (voltage adjustment circuit) 2 as output adjustment means. The output detection unit 6 detects, for example, an output voltage Vo as an output of the fuel cell power generation unit (cell) 101, and outputs a detection signal corresponding to the output voltage Vo to the control unit 7.

  The DC-DC converter 2 includes a switching element and an energy storage element (not shown). The DC-DC converter 2 stores / releases electric energy generated by the fuel cell body 1 by the switching element and the energy storage element, An output generated by boosting a relatively low output voltage to a sufficient voltage is generated. The output of the DC-DC converter 2 is supplied to the auxiliary power supply 4.

  Although the standard boost type DC-DC converter 2 is shown here, other circuit systems can be used as long as the boost operation is possible.

  An auxiliary power supply 4 is connected to the output end of the DC-DC converter 2 to constitute a so-called hybrid fuel cell. The auxiliary power supply 4 can be charged by the output of the DC-DC converter 2 and supplies a current to an instantaneous load fluctuation of the electronic device main body 3, and the fuel cell is in a fuel-depleted state. When the main body 1 is incapable of generating power, it is used as a driving power source for the electronic device main body 3. As the auxiliary power source 4, a chargeable / dischargeable secondary battery (for example, a lithium ion rechargeable battery (LIB)) or an electric double layer capacitor) is used.

  An auxiliary power supply output detector 8 and a fuel supply control circuit 5 are connected to the auxiliary power supply 4. The auxiliary power supply output detection unit 8 detects, for example, an output voltage VB as an output of the auxiliary power supply 4, and outputs a detection signal corresponding to the output voltage VB to the control unit 7. The fuel supply control circuit 5 controls the operation of the pump 104 using the auxiliary power source 4 as a power source, and controls the pump 104 on / off based on an instruction from the control unit 7.

  A controller 7 is connected to the fuel supply control circuit 5. The control unit 7 controls the entire system, and includes an output setting unit 701, an operation mode selection unit 702, a timer 703, and a pump control signal generation unit 704. The output setting unit 701 stores a set value for the output voltage VB of the auxiliary power supply 4 which is a reference for selecting an operation mode. In this case, the set value is set to an upper limit value VBL of the output voltage VB and an intermediate value VBM as a predetermined value equal to or lower than the upper limit value VBL. Here, the upper limit value VBL is the upper limit value of the charging voltage of a secondary battery or the like applied as the auxiliary power supply 4, and the intermediate value VBM is lower than the upper limit value VBL. For example, the auxiliary power supply 4 can respond to a load request. It is a limit value. The operation mode selection means 702 compares the detection signal of the auxiliary power supply output detection unit 8 with the upper limit value VBL and the intermediate value VBM for the output voltage VB of the auxiliary power supply 4 set in the output setting unit 701, and from this comparison result, the operation mode is selected. The fuel consumption priority mode or the output priority mode is selected. The timer 703 counts elapse of time at the time of mode transition. The count of the timer 703 prevents a phenomenon in which mode switching is frequently repeated in the vicinity of a threshold value for determining each mode transition. As a standard of this count, 1 to 5 times the time required for mode switching is preferable. The pump control signal generator 704 outputs an on / off signal for the pump 104 in accordance with the operation mode selected by the operation mode selection means 702.

  Next, the operation of the embodiment configured as described above will be described.

  Now, according to the start instruction of the fuel cell system, the flowchart shown in FIG.

  First, in step 401, the fuel cell system is set to the startup mode. In this case, fuel is supplied to the fuel cell power generation unit 101 via the pump 104. The output generated by the fuel cell power generation unit 101 is boosted to a sufficient voltage by the DC-DC converter 2 and supplied to the electronic device main body 3 and charged to the auxiliary power supply 4.

  In this state, the process proceeds to step 402. In step 402, the auxiliary power supply output detector 8 detects the output voltage VB of the auxiliary power supply 4. Further, the operation mode selection means 702 determines whether the output voltage VB at this time is equal to or lower than the upper limit value VBL of the output voltage VB set in the output setting unit 701. Here, if the output voltage VB is equal to or lower than the upper limit value VBL, it is determined as YES and the process proceeds to Step 403.

  On the other hand, if the output voltage VB is equal to or higher than the upper limit value VBH, the process proceeds to step 404, and the fuel cell body 1 is shifted to the end standby mode. In this case, the output of the fuel cell main body 1 is opened to stop the charging of the auxiliary power source 4, and the load request of the electronic device main body 3 is made to respond only by the auxiliary power source 4. In step 405, when it is confirmed that the mode transition time has elapsed from the count of the timer 703, the process proceeds to step 406, where it is determined again whether the output voltage VB of the auxiliary power source 4 has become equal to or lower than the upper limit value VBL. Here, if the output voltage VB is equal to or lower than the upper limit value VBH and it is determined YES, the process proceeds to step 403. In this case, when it is determined in step 406 that the output voltage VB of the auxiliary power supply 4 still does not become the upper limit value VBH or less, it is determined that the system is defective and the operation is terminated (step 407).

  In step 403, it is determined whether the output voltage VB of the auxiliary power supply 4 is equal to or lower than the upper limit value VBH and equal to or higher than the intermediate value VBM. Here, when the output voltage VB is equal to or higher than the intermediate value VBM, it is determined that the charging state of the auxiliary power supply 4 is sufficient and the load request of the electronic device main body 3 can be handled, and the process proceeds to Step 408. In step 408, the operation of the fuel cell body 1 is shifted to the fuel efficiency priority mode. This fuel efficiency priority mode is based on fuel consumption efficiency in the fuel cell main body 1, and the control unit 7 detects the output voltage Vo of the fuel cell power generation unit (cell) 101 detected by the output detection unit 6 and the temperature sensor 106. By referring to the heat generation temperature of the fuel cell power generation unit (cell) 101 detected from the pump, the pump control signal generation unit 704 outputs an on / off signal of the pump 104 corresponding to the fuel efficiency priority mode, and controls the fuel cell main body 1 The voltage Vc and the control temperature Tc are controlled to predetermined values set in advance. In this fuel efficiency priority mode, for example, the control temperature Tc = 43 ° C. and the control voltage Tc = 0.38V are set, and an output of 0.37 W and a fuel efficiency of 1.45 Wh / g are obtained.

  Thereafter, when the elapse of the mode transition time is confirmed by the count of the timer 703 in step 410, the process proceeds to step 411. The count of the timer 703 prevents a phenomenon in which mode switching is frequently repeated in the vicinity of the threshold value for determining the mode transition as described above. As a standard of this count, 1 to 5 times the time required for mode switching is preferable. For example, in mode switching, if the time required to raise the temperature by 6 ° C. is 5 minutes, or if the time required to lower the temperature by 6 ° C. is 5 minutes, the count for that is set to 10 minutes can do. In step 411, it is determined whether the output voltage VB of the auxiliary power source 4 has increased. Here, if the output voltage VB rises and it is determined YES, it is determined that the charging voltage of the auxiliary power supply 4 is still sufficient, the process returns to step 408, and the fuel consumption priority mode is continued. If it is determined in step 411 that the output voltage VB of the auxiliary power supply 4 cannot be increased, the process returns to step 402, and the operations in and after step 402 are repeated.

  On the other hand, if it is determined in step 403 that the output voltage VB of the auxiliary power source 4 is equal to or lower than the intermediate value VBM, it is determined that the charging state of the auxiliary power source 4 is insufficient and it is difficult to respond to the load request of the electronic device body 3. Then, the process proceeds to Step 409. In step 409, the operation of the fuel cell body 1 is shifted to the output priority mode. This output priority mode takes into account the output priority of the fuel cell main body 1, and the control unit 7 detects the output voltage Vo of the fuel cell power generation unit (cell) 101 detected by the output detection unit 6 and the temperature sensor 106. The pump control signal generating unit 704 outputs an on / off signal of the pump 104 according to the output priority mode with reference to the heat generation temperature of the fuel cell power generation unit (cell) 101, and the control voltage Vc of the fuel cell main body 1 and The control temperature Tc is controlled to a predetermined value set in advance. In this output priority mode, for example, the control temperature Tc = 49 ° C. and the control voltage Tc = 0.36V are set, and an output of 0.75 W and a fuel consumption of 1.0 Wh / g are obtained. That is, in the output priority mode, the fuel efficiency is lower than that in the fuel efficiency priority mode, but a larger output can be obtained.

  Thereafter, when the elapse of the mode transition time is confirmed by the count of the timer 703 in step 412, the process returns to step 402, and the operation after step 402 is repeated thereafter.

  Here, an actual usage example will be described.

In this case, the fuel cell system uses a fuel cell power generation unit 101 having an area of 3.5 cm ² and a cell series number of 4 cells, and a fuel storage unit 102 having a capacity of 7.0 mL (5.54 g). ing. The auxiliary power source 4 is a lithium ion rechargeable battery (LIB) having a capacity of 600 mAh, an upper limit potential of 4.0 V and a lower limit potential of 3.3 V, and a DC-DC converter 2 having an operating efficiency of 80%. is doing.

  In the fuel efficiency priority mode, control is performed such that the output is 0.37 W and the fuel efficiency is 1.45 Wh / g, and in the output priority mode, the output is 0.75 W and the fuel efficiency is 1.0 Wh / g.

  When such a fuel cell system is applied to a power source of a mobile phone as the electronic device body 3, for example, when a businessman who frequently uses a mobile phone only during the day is examined, the following results are obtained. It was. In this case, when the usage status of the cellular phone by the businessman is checked every hour, the cellular phone is frequently used from 9:00 to 18:00 in one day, and the average power consumption for each hour during this period is 365 mWh. The average power consumption for each hour from 18:00 to 9:00 on the next day was 5 mWh on average.

  When a method for selecting the fuel efficiency priority mode and the output priority mode according to the output voltage VB of the auxiliary power supply 4 of the present invention described above is adopted for the mobile phone in such a usage situation, the output voltage VB of the auxiliary power supply 4 is adopted. Was found to change as shown in FIG. In this case, in FIG. 5A, when the output voltage VB = 4.0V is the upper limit value VBH and the output voltage VB = 3.6V is the intermediate value VBM, the output voltage VB is equal to or higher than the upper limit value VBH. From 3 o'clock to 9 o'clock shown in 5 (a), charging of the auxiliary power supply 4 is stopped and the auxiliary power supply 4 responds to the load request of the mobile phone. When the output voltage VB is lower than the upper limit value VBH and higher than the intermediate value VBM, that is, from 9 o'clock to 11 o'clock shown in FIG. Is determined to be sufficient to respond to the load request, and the operation of the fuel cell body 1 is shifted to the fuel efficiency priority mode. As a result, the fuel cell main body 1 is operated with an output of 0.37 W and fuel consumption of 1.45 Wh / g in consideration of fuel consumption efficiency. Thereafter, when the output voltage VB drops below the intermediate value VBM, that is, from 11 o'clock to about 18 o'clock shown in FIG. Therefore, the operation of the fuel cell body 1 is shifted to the output priority mode. As a result, the fuel cell main body 1 is operated with an output of 0.75 W in consideration of output priority and a fuel consumption of 1.0 Wh / g.

  On the other hand, when the method of selecting the fuel efficiency priority mode and the output priority mode is not adopted and only the output priority mode that can respond to the load request is adopted, the output voltage VB of the auxiliary power source 4 is as shown in FIG. Turned out to change. In this case, while the load demand of the cellular phone from 9:00 to 18:00 shown in FIG. 5B is large, the operation of the fuel cell body 1 is performed with the output priority mode of 0.75 W and the fuel consumption of 1.0 Wh / g. Operation is performed.

  As a result, in the operation only in the output priority mode shown in FIG. 5B, the entire output voltage VB of the auxiliary power source 4 is maintained at a high level, whereas the fuel consumption priority mode and the output priority mode shown in FIG. In the operation in which the fuel consumption priority mode is selected, the output voltage VB of the auxiliary power supply 4 can be kept low due to the driving effect of the fuel efficiency priority mode. It was proved that the fuel consumption rate could be greatly improved in the operation in which the fuel consumption priority mode and the output priority mode were selected, but it was possible to operate in 1.3 days.

  Therefore, in this way, the output voltage VB corresponding to the charging voltage of the auxiliary power supply 4 to which the power generation output of the fuel cell main body 1 is supplied is detected, and this output voltage VB is not more than the upper limit value VBL and not less than the intermediate value VBM. In this case, it is determined that the charging voltage of the auxiliary power source 4 is sufficient and there is room for the load request of the electronic device main body 3, and the mode shifts to the fuel consumption priority mode considering the fuel consumption efficiency, and the output voltage VB is the upper limit value VBL In the following, when the intermediate value VBM or less, it is determined that the charging voltage of the auxiliary power supply 4 is insufficient and there is no room for the load request of the electronic device main body 3, and the output priority mode is considered in consideration of output priority. I made it. As a result, the fuel cell main body 1 selects the fuel efficiency priority mode when the output voltage VB of the auxiliary power supply 4 is sufficiently large with respect to the load demand of the electronic device main body 3, so the fuel consumption rate during this period is greatly increased. Can be improved economically and advantageously. Further, when the load demand of the electronic device body 3 becomes large and the output voltage VB of the auxiliary power supply 4 decreases, the output priority mode is selected, so that it is possible to reliably cope with an increase in load demand. In addition, the fuel efficiency priority mode and the output priority mode are selected only by detecting the output voltage VB of the auxiliary power source 4, and there is no need to measure the power consumption during the operation of the electrical equipment as in the prior art. Easy to do. Furthermore, since the fuel consumption priority mode and the output priority mode are obtained by controlling the control voltage Vc and the control temperature Tc while the fuel concentration remains constant, the problem that the control system for supplying fuel becomes complicated can be avoided. .

  In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not change the summary. For example, in the above-described embodiment, the outputs in the fuel consumption priority mode and the output priority mode are output from the output voltage Vo of the fuel cell power generation unit 101 detected by the output detection unit 6 by the control unit 7 and the temperature sensor 106. Although the control voltage Vc and the control temperature Tc of the fuel cell main body 1 are controlled by referring to the detected heat generation temperature of the fuel cell power generation unit 101, only one of the control voltage Vc and the control temperature Tc is controlled. You may make it obtain. In the above-described embodiment, the output voltage of the auxiliary power source 4 is detected and the fuel consumption priority mode or the output priority mode is selected based on the output voltage. However, the output current of the auxiliary power source 4 is detected. The fuel consumption priority mode or the output priority mode may be selected based on the output current.

  Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and is described in the column of the effect of the invention. If the above effect is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

  Further, the vaporized component of the liquid fuel supplied to the fuel cell power generation unit may be all supplied as the vaporized component of the liquid fuel, but the present invention is applied even when a part is supplied in the liquid state. be able to.

1 is a diagram showing a schematic configuration of a fuel cell system according to a first embodiment of the present invention. Sectional drawing for demonstrating in detail the fuel cell main body of 1st Embodiment. The perspective view of the fuel distribution mechanism used for the fuel cell main body of 1st Embodiment. The flowchart for demonstrating operation | movement of 1st Embodiment. The figure explaining the change of the output voltage of the auxiliary power supply in the actual usage example of 1st Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell main body, 101 ... Fuel cell electric power generation part 102 ... Fuel accommodating part, 103 ... Flow path 104 ... Pump, 105 ... Fuel distribution mechanism 106 ... Temperature sensor, 2 ... DC / DC converter, 3 ... Electronic equipment main body 4 ... Auxiliary power supply, 5 ... Fuel supply control circuit 6 ... Output detection unit, 7 ... Control unit,
701 ... Output setting unit, 702 ... Operation mode selection unit,
703 ... Timer, 704 ... Pump control signal generator,
8 ... Auxiliary power output detector,
DESCRIPTION OF SYMBOLS 11 ... Anode catalyst layer, 12 ... Anode gas diffusion layer 13 ... Anode, 14 ... Cathode catalyst layer 15 ... Cathode gas diffusion layer, 16 ... Cathode 17 ... Electrolyte membrane, 18 ... Cover plate 19 ... O-ring, 21 ... Fuel inlet 22 ... Fuel discharge port, 23 ... Fuel distribution plate 24 ... Gap

Claims (4)

A fuel cell main body that generates electric power by supplying fuel; and
An auxiliary power source that is charged by the power generation output of the fuel cell body and used as a power source for the electronic device body,
Output detection means for detecting the output of the auxiliary power supply;
An operation mode selection means for selecting a fuel efficiency priority mode considering fuel efficiency priority or an output priority mode considering output priority based on the output detected by the output detection means;
Control means for controlling the output of the fuel cell body according to the priority mode selected by the operation mode selection means;
A fuel cell system comprising:   The operation mode selection means selects the fuel consumption priority mode when the output of the auxiliary power detected by the output detection means is less than or equal to an upper limit value and greater than or equal to a predetermined value, and when the output is less than or equal to the predetermined value, the output priority 2. The fuel cell system according to claim 1, wherein a mode is selected.   The control means obtains the output of the fuel cell main body according to the fuel consumption priority mode or the output priority mode by controlling at least one of a control voltage and a control temperature of the fuel cell main body. Or the fuel cell system of 2.   An electronic device using the fuel cell system according to claim 1 as a power source.

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