JP2007059312A - Electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electronic equipment equipped with a fuel cell having excellent power generation efficiency. <P>SOLUTION: This electronic equipment is provided with: an electronic equipment body having a heat generation part; a fuel cell body for supplying power to the electronic equipment body; a fuel storage tank for storing a liquid fuel; a fuel supply system connected to the fuel storage tank and having a fuel supply pump for transporting the liquid fuel to the fuel cell body and a passage for running the liquid fuel; and a heat transmitter for supplying heat generated in the heat generation part to the liquid fuel. The electronic equipment is characterized in that the fuel supply system is equipped with a gas-liquid separator for separating bubbles generated from the liquid fuel with heat supplied thereto from the liquid fuel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic device, and more particularly to an electronic device including a portable electronic device body such as a mobile phone, a portable terminal, a notebook personal computer, and an electronic camera and a fuel cell body as a power source.

  With the arrival of the information society in recent years, the amount of information handled by electronic devices such as personal computers has increased dramatically, and the power consumption of electronic devices has also increased remarkably. In particular, in portable electronic devices, an increase in power consumption is a problem with an increase in processing capability. Currently, in such portable electronic devices, lithium ion batteries are generally used as power sources, but the energy density of lithium ion batteries is approaching the theoretical limit. Therefore, in order to extend the continuous use period of the portable electronic device, there is a limitation that the power consumption must be reduced by suppressing the CPU driving frequency.

  Under such circumstances, it is expected that the continuous use period of portable electronic devices will be greatly improved by using a fuel cell with a large energy density as a power source for electronic devices instead of lithium ion batteries. Yes.

  A fuel cell is composed of a fuel electrode and an oxidant electrode, and an electrolyte provided therebetween. The fuel cell is supplied with fuel, and the oxidant electrode is supplied with an oxidant to generate electricity by an electrochemical reaction. As a fuel, hydrogen is generally used, but in recent years, a fuel using liquid fuel has been developed. Development of a methanol reforming type in which methanol is reformed to produce hydrogen by using inexpensive and easy-to-handle methanol and a direct type fuel cell in which methanol is directly used as a fuel has been actively performed.

  When hydrogen is used as the fuel, the reaction at the fuel electrode is represented by the following formula (1).

^{_{3H 2 → 6H + + 6e -}} (1)
When methanol is used as the fuel, the reaction at the fuel electrode is represented by the following equation (2).

_{CH 3 OH + H 2 O →} 6H + + CO 2 + 6e - (2)
In either case, the reaction at the oxidant electrode is represented by the following formula (3).

(3/2) O ₂ + 6H ⁺ + 6e ⁻ → 3H ₂ O (3)
In particular, in a direct type fuel cell, hydrogen ions can be obtained from an aqueous methanol solution, so that a reformer or the like is not required, and it can be reduced in size and weight, and applied to a portable electronic device. The benefits are great. Further, since a liquid methanol aqueous solution is used as a fuel, the energy density is very high.

  Since the direct-type fuel cell has a unit cell with a generated voltage of 1 V or less, it is necessary to connect a plurality of cells in series in order to generate a high voltage in order to apply to a portable device such as a mobile phone. . In the case of a fuel cell for automobiles and home use, it is common to have a stack structure in which unit cells are connected vertically, but in the case of a direct methanol solid polymer fuel cell for portable devices. In many cases, a method of connecting in a plane is used because of restrictions on the thickness of the device.

  In recent years, as shown in Non-Patent Document 1, a system that can be used for a long time by incorporating a fuel cell cartridge into a device and replacing the fuel cartridge when the fuel is used has been studied.

  In addition, with the miniaturization of portable devices, it is necessary to increase the output of direct methanol solid polymer fuel cells. In order to increase the output of the direct methanol solid polymer fuel cell, a method of heating liquid fuel is known. In general, in the case of a direct methanol solid polymer fuel cell, the power generation efficiency can be increased by operating the fuel cell at a relatively high temperature of about 80 ° C. to 90 ° C. for the liquid fuel.

  Therefore, some conventional fuel cell systems using direct methanol solid polymer fuel cells are additionally provided with a fuel cell heating device. However, as a result, there is a problem that the system becomes larger.

In recent years, a fuel cell system that supplies heat from an electronic device having a heat generating portion to a fuel storage container has been proposed (see Patent Document 1).
Fuel cell 2005 Nikkei BP 72 JP 2002-231290 A

  However, when the liquid fuel of the fuel cell is heated as in Patent Document 1, the dissolved gas in the liquid fuel becomes bubbles, which deteriorates the performance of the fuel supply pump and causes a problem of hindering fuel supply. Furthermore, when bubbles enter the fuel cell, the reaction area at the fuel electrode is reduced, resulting in poor power generation efficiency.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide an electronic device including a fuel cell with high power generation efficiency.

  The above object of the present invention can be achieved by the following means.

An electronic device according to claim 1 is an electronic device main body provided with a heat generating portion;
A fuel cell body for supplying power to the electronic device body;
A fuel storage tank for storing liquid fuel;
A fuel supply system connected to the fuel storage tank and having a flow path through which the liquid fuel flows in the fuel cell body;
A heat transfer body for supplying heat generated in the heat generating section to the liquid fuel,
The fuel supply system includes a gas-liquid separator that separates bubbles generated from the liquid fuel supplied with the heat from the liquid fuel.

  An electronic device according to a second aspect is the electronic device according to the first aspect, further comprising a fuel supply pump that transports the liquid fuel to the fuel cell main body.

  An electronic device according to a third aspect is the electronic device according to the first or second aspect, wherein the gas-liquid separator is arranged upstream of the fuel supply pump.

  According to the present invention, the heat generated in the heat generating part of the electronic device main body is used for heating the liquid fuel that is the fuel of the fuel cell main body, and bubbles generated from the heated liquid fuel are removed by the gas-liquid separator. As a result, the temperature of the reaction part of the fuel cell body, particularly the temperature of the fuel electrode, can be operated at a relatively high temperature, the power generation efficiency is increased, and the bubbles in the liquid fuel are removed. It is possible to prevent the power generation efficiency from being reduced due to the adhesion.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a conceptual diagram of an electronic device according to a first embodiment of the present invention. In FIG. 1, an electronic device 10 includes an electronic device main body 15 having a heat generating portion 30, a fuel cell main body 80 that supplies power to the electronic device main body 15, a fuel storage tank 20 that stores liquid fuel used in the fuel cell, and a fuel storage tank. 20, a fuel supply pump 70 that transports liquid fuel to the fuel cell main body 80 through the flow path 50 (herein, the fuel supply system including the flow path 50 and the fuel supply pump 70) is generated in the heat generating unit 30. A heat transfer body 40 that supplies heat to the liquid fuel, and a gas-liquid separator 60 that separates bubbles generated from the liquid fuel supplied with heat from the liquid fuel.

  The heat generated in the heat generating portion 30 when the electronic device main body operates is supplied to the liquid fuel passing through the flow path 50 via the heat transfer body 40. In the liquid fuel heated by supplying heat, the saturated solubility of a gas such as carbon dioxide is lowered, so that the dissolved gas becomes bubbles. Bubbles generated in the liquid fuel can be separated and removed by the gas-liquid separator 60 arranged in the middle of the flow path 50. Since the liquid fuel from which the bubbles are removed is supplied to the fuel cell main body 80, electric power can be generated efficiently, and electric power can be satisfactorily supplied to the electronic device main body. The fuel cell main body 80 mainly includes an electrolyte membrane 82, a fuel electrode 81, and an oxidant electrode 83.

  As the electronic device main body 15, a portable type equipped with a heat generating unit 30 is suitable, and for example, portable electronic devices such as a mobile phone, a portable terminal, a notebook computer, and an electronic camera are preferable examples. Further, the heat generating part 30 may be anything that generates heat during use, and the type thereof is not particularly limited. However, the heat generating part 30 is not a member intended to generate heat, but generates heat as a by-product due to energization for operation. Such a member is suitable. Although the heat generating unit 30 varies depending on the configuration of the electronic device main body 15, in many cases, a central processing element (CPU), a memory chip, a display display element, a backlight thereof, or the like is a preferable example. An electronic camera includes a solid-state image sensor.

  In FIG. 1, an example in which the electronic device main body 15 includes one heat generating unit 30 is illustrated, but two or more heat generating units 30 may be included. Moreover, although the fuel supply system from the fuel storage tank 20 is one system, a plurality of fuel supply systems may be provided. In particular, when the liquid fuel stored in the fuel storage tank 20 is divided into a plurality of fuel storage tanks according to the type, a number of fuel supply systems corresponding to the type may be provided.

  The fuel cell main body 80 is not particularly limited as long as it uses liquid fuel and operates near room temperature. As the fuel cell main body 80, specifically, a polymer electrolyte fuel cell is a preferred example.

  As the liquid fuel, a type in which a liquid fuel composed of a mixture of a liquid organic compound containing oxygen such as methanol, ethanol, propanol, formic acid, sodium formate, formaldehyde, ethylene glycol and water is supplied is preferable. In particular, the type of fuel cell that supplies methanol aqueous solution as a fuel, that is, direct methanol solid polymer fuel cell, is inexpensive and easy to store, and the electrochemical reaction is comparable near room temperature in the presence of a catalyst. It is suitable as a power source for portable electronic devices.

  As a liquid fuel storage method, the fuel storage tank 20 is preferably incorporated in the electronic device main body 15 from the viewpoint of miniaturization. In particular, if the fuel storage tank 20 is of a removable cartridge type, it is convenient for long-term use. Further, the fuel storage tank 20 may be divided into a methanol storage tank and a water storage tank when, for example, an aqueous methanol solution is used as fuel.

  The heat transfer body 40 supplies the heat generated in the heat generating unit 30 to the liquid fuel in the fuel supply system. Further, the heat transfer body 40 may heat the air supplied to the oxidant electrode 83 which is a constituent element of the fuel cell main body 80 at the same time as the liquid fuel is heated. You may make it heat the whole.

  Thus, by heating the liquid fuel supplied to the fuel cell main body 80 and the air supplied to the oxidant electrode 83, the power generation efficiency of the fuel cell main body 80 can be increased.

  As a material used for the heat transfer body 40, a material having a high thermal conductivity and a low price is preferable. For example, copper, a copper alloy, aluminum, an aluminum alloy, or the like is preferably used.

  As a method of transferring heat from the heat transfer body 40 to the liquid fuel, a pipe may be used for the fuel supply system and the pipe may be brought into contact with the heat transfer body 40. However, the fuel supply system is connected to the heat transfer body 40 itself. It is also possible to form a flow path 50 as FIG. 2 shows a schematic diagram of a preferable shape of the flow path 50 of the fuel supply system formed in the heat transfer body 40.

  As shown in FIG. 2, by forming the zigzag flow path 50 inside the heat transfer body 40, the residence time of the liquid fuel in the heat transfer body 40 becomes longer, and the heat transfer efficiency can be increased.

  Further, since the temperature of the heat transfer body 40 is not sufficiently increased when the electronic device main body 15 is started, the liquid fuel can be supplied to the fuel cell main body 80 after being heated by the following operation method. preferable. That is, the liquid fuel is caused to flow by the fuel supply pump 70 up to the vicinity of the outlet of the heat transfer body 40, where the fuel supply pump 70 is temporarily stopped and the temperature of the liquid transfer fuel is increased by increasing the temperature of the heat transfer body 40. The driving of the supply pump 70 is resumed. By doing in this way, the output fall at the time of starting of the electronic device main body 15 can be prevented.

  Bubbles generated in the liquid fuel are removed from the heated liquid fuel by the gas-liquid separator 60 after passing through the heat transfer body 40. As the gas-liquid separator 60, one having a configuration for trapping and removing bubbles in the liquid fuel as shown in FIGS. 3 (a) and 3 (b) can be used. In the separator of FIG. 3, the liquid fuel that has been heated and generated bubbles enters the bubble trap 62 from the inlet 61, and most of the bubbles are caught and captured by the stepped portion 64. When the thinned bubbles become large, they are discharged from the bubble discharge port 63 into the atmosphere. Therefore, mixing of bubbles into the fuel supply pump 70 is suppressed. Details of the gas-liquid separator 60 shown in FIG. 3 are described in Japanese Patent Application No. 2004-181546 filed by the applicant of the present application. In addition, it is not limited to the separator including the trap using the step as described above, and any method can be used as long as it can separate and remove bubbles from the liquid.

  The fuel supply pump 70 is not particularly limited as long as it can supply a certain amount of liquid fuel, which is fuel of the fuel cell, to the fuel cell main body 80. However, a small amount of liquid can be increased with a simple configuration using a piezoelectric element. A micropump that can be accurately conveyed is preferable. Details of the micropump are described in JP-A-2001-322099.

  As described above, the electronic apparatus according to this embodiment including the gas-liquid separator 60 that separates the bubbles generated from the liquid fuel supplied with heat from the liquid fuel efficiently generates bubbles generated from the heated liquid fuel. Can be removed. By supplying this heated liquid fuel from which bubbles have been removed to the fuel cell main body 80, it is possible to prevent bubbles from adhering to the fuel electrode 81 constituting the fuel cell main body 80, and the electrolyte membrane 82 and Since the temperature at the fuel electrode 81 and the oxidant electrode 83 can be kept high, the output density of the fuel cell can be improved.

  FIG. 4 shows a conceptual diagram of an electronic apparatus according to the second embodiment of the present invention. In the second embodiment of the present invention, the fuel storage tank 20 in the first embodiment is divided into a high concentration liquid fuel storage tank 21 and a water storage tank 22 for dilution. Are mixed and diluted by the fuel supply pumps 71 and 72, and supplied to the fuel electrode 81 side of the fuel cell main body 80 through the flow path 50. At this time, the high-concentration liquid fuel and water are heated via the heat transfer body 40 by the heat generated in the heat generating unit 30 as in the first embodiment. Thereafter, as shown in detail in FIG. 5, the gas-liquid separator 60 and the fuel supply pumps 71 and 72 are used to remove bubbles generated from the heated high-concentration liquid fuel and water, and then mixed and diluted. The fuel cell body 80 is supplied. In this way, even if the liquid fuel is divided into the high concentration liquid fuel and water and separated into the separate storage tanks 21 and 22, each of them is heated and the bubbles are removed, thereby improving the output density of the fuel cell. I can do it.

  In the second embodiment, one heating unit 30 and one heat transfer body 40 are used, but a plurality of heating units and heat transfer bodies 40 may be provided. Further, each of the high-concentration liquid fuel and the water is configured to mix and dilute after passing through the gas-liquid separator 60, but after the respective liquids are mixed and diluted, the gas-liquid separator 60 is allowed to pass through. You may comprise so that a bubble may be removed.

  FIG. 6 shows a conceptual diagram of an electronic apparatus according to the third embodiment of the present invention. In the third embodiment of the present invention, in the second embodiment, an air passage 51 and an air supply pump 73 through which air as an oxidant supplied to the oxidant electrode 83 passes are added. Air in the air passage 51 is heated by the heat of the heat generating part 30 through the heat transfer body 40 and supplied to the oxidant electrode 83 of the fuel cell main body 80 by the air supply pump 73. By heating the air supplied to the oxidizer electrode 83 in this way, the temperature of the fuel cell main body 80 can be increased more quickly, and the output density of the fuel cell can be improved. Excess air after the reaction with the water generated at the oxidizer electrode 83 is discharged from the air discharge port 52.

  FIG. 7 shows a conceptual diagram of an electronic apparatus according to the fourth embodiment of the present invention. In the fourth embodiment of the present invention, a Peltier element 90 is attached between the heat generating portion 30 and the heat transfer body 40 in the third embodiment. The Peltier element 90 has an effect of cooling the heat generating portion 30 and heating the heat transfer body 40 on the surface opposite to the heat generating portion 30. By attaching the Peltier element 90 between the heat generating part 30 and the heat transfer body 40, the heat generating part 30 can be cooled more efficiently by operating the Peltier element 90 simultaneously with the power-on of the electronic device main body 15. In addition, the temperature of the liquid fuel, water, and air can be raised in a shorter time via the heat transfer body 40, and the power generation efficiency can be increased more stably.

  FIG. 8 shows a conceptual diagram of an electronic apparatus according to the fifth embodiment of the present invention. In the fifth embodiment of the present invention, a fuel circulation passage 53 and valves 100 and 101 are added to the first embodiment. When the electronic device main body 15 is activated, the temperature of the heat transfer body 40 is not sufficiently increased. Therefore, by closing the valve 100 and opening the valve 101, liquid fuel is circulated in the fuel circulation passage 53, and the heat transfer body 40. Sufficiently increases the temperature of the liquid fuel. Thereafter, by opening the valve 100 and closing the valve 101, the temperature rises sufficiently, and the liquid fuel from which bubbles have been removed by the gas-liquid separator 60 is supplied to the fuel cell body 80. By doing in this way, the power generation efficiency of the fuel cell at the initial startup of the electronic device main body 15 can be sufficiently increased. The opening and closing of the valves 100 and 101 at this time is preferably controlled by detecting the temperature of the liquid fuel in the fuel supply passage 50 with a sensor.

  As described above, according to each embodiment of the present invention, the air supplied to the liquid fuel, the water for dilution, and the oxidant electrode is not required by using the heat of the heat generating part of the electronic device body without requiring a special heating device. By heating and removing bubbles from the heated liquid fuel by a gas-liquid separator, an electronic device can be provided without increasing the size of a fuel cell with high power generation efficiency.

The conceptual diagram of the electronic device which concerns on the 1st Embodiment of this invention is shown. The schematic shape of the flow path of the fuel supply system formed in the heat exchanger according to the present invention is shown. The schematic of the gas-liquid separator which concerns on this invention is shown. The conceptual diagram of the electronic device which concerns on the 2nd Embodiment of this invention is shown. 1 shows a schematic diagram of a gas-liquid separator and a fuel supply pump according to the present invention. FIG. The conceptual diagram of the electronic device which concerns on the 3rd Embodiment of this invention is shown. The conceptual diagram of the electronic device which concerns on the 4th Embodiment of this invention is shown. The conceptual diagram of the electronic device which concerns on the 5th Embodiment of this invention is shown.

Explanation of symbols

10, 11, 12, 13, 14 Electronic equipment 15 Electronic equipment body 20 Fuel storage tank 21 High-concentration liquid fuel storage tank 22 Water storage tank 30 Heat generating part 40 Heat transfer body 50 Flow path 51 Air passage 52 Air discharge port 53 Fuel Circulation path 60 Gas-liquid separator 61 Inlet 62 Bubble trap part 63 Bubble outlet 64 Step part 70, 71, 72 Fuel supply pump 73 Air supply pump 80 Fuel cell body 81 Fuel electrode 82 Electrolyte membrane 83 Oxidant electrode 90 Peltier element 100, 101 valves

Claims (3)

An electronic device body with a heat generating part;
A fuel cell body for supplying power to the electronic device body;
A fuel storage tank for storing liquid fuel;
A fuel supply system connected to the fuel storage tank and having a flow path through which the liquid fuel flows in the fuel cell body;
A heat transfer body for supplying heat generated in the heat generating section to the liquid fuel,
The electronic apparatus according to claim 1, wherein the fuel supply system includes a gas-liquid separator that separates bubbles generated from the liquid fuel supplied with the heat from the liquid fuel. The electronic apparatus according to claim 1, further comprising a fuel supply pump that transports the liquid fuel to the fuel cell main body. The electronic apparatus according to claim 1, wherein the gas-liquid separator is disposed upstream of the fuel supply pump.

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