JP4665381B2 - Fuel cell system and electrical equipment - Google Patents

Description

  The present invention relates to a fuel cell system in which fuel is supplied from a fuel supply tank, and further relates to an electric device incorporating the fuel cell system.

  A fuel cell is a power generation device that generates power by electrochemically reacting a fuel fluid such as hydrogen gas or methanol with an oxidizing fluid (oxygen contained in air). For example, in the case of a solid polymer type fuel cell, each power generator portion has a structure in which an electrolyte membrane made of a solid polymer is sandwiched between an oxygen side electrode and a fuel side electrode. Air is supplied to supply the fuel, fuel fluid is supplied to the fuel side electrode, and power generation is performed by the electrochemical reaction.

  During power generation, in a polymer electrolyte fuel cell, ions (protons) move through an electrolyte membrane that is an ion exchange membrane and functions as a proton conductor membrane, and reacts with oxygen on the oxygen side electrode to generate a current. At the same time, water is generated at the oxygen side electrode. The power generation part of a fuel cell is called an electrolyte membrane / electrode assembly or MEA (Membrane and Electrode Assembly), and this electrolyte membrane / electrode assembly is a separator in which a fuel fluid channel and an air channel are formed. A fuel cell having a stacked structure (stacked structure) is configured by stacking a plurality of power generation cells as a power generation cell.

The above-described fuel cell has been attracting attention in recent years as a clean power source in which the product generated by power generation is water and does not pollute the environment. For example, in a large system such as an electric vehicle or a residential power system While it is expected to be put to practical use, taking advantage of the small size and light weight of the polymer electrolyte fuel cell, its application as a power source for portable electric devices such as notebook personal computers is also being studied ( For example, see Patent Document 1). In a fuel cell used for such an application, it is important that a required power can be stably output and a portable size is achieved, and various technological developments are actively performed. For example, the invention described in Patent Document 1 discloses a polymer electrolyte fuel cell for mounting on an ultra-small device integrated in one package.
JP-A-9-213359

  By the way, for example, in a portable electric device such as a notebook personal computer, running out of a battery causes a loss of data or the like, which requires a lot of labor for re-input, resulting in a heavy burden on the operator.

  On the other hand, as described above, a fuel cell is a system that uses hydrogen and oxygen to cause an electrochemical reaction to generate electrical energy. Usually, the fuel supply amount (methanol concentration in a direct methanol fuel cell) is reduced. Operation is performed under the optimum conditions such that the maximum output can be obtained, and electric devices are operated by extracting necessary power. In this case, the amount of fuel supplied to the fuel cell is constant despite the fluctuations in the power consumption of the electrical equipment, so that the fuel is wasted.

  The present invention has been proposed to solve the above-described problems. First, it is an object of the present invention to provide a fuel cell system and an electrical device that can eliminate sudden battery exhaustion. Furthermore, it aims at providing the fuel cell system and electric equipment which can give a sense of security to the operator who uses it. Secondly, an object of the present invention is to provide a fuel cell system and an electric device that can suppress the consumption of fuel, increase the power generation time of the fuel cell, and suppress the consumption of useless fuel. .

A fuel cell system and an electric device according to the present invention are a direct methanol fuel cell system including a fuel cell and a fuel supply tank that supplies fuel to the fuel cell. In the energy saving mode according to the power consumption of the electric device . When the user is notified that the operation is possible and there is a signal input for selecting the energy saving mode, the concentration of the aqueous methanol solution supplied to the fuel cell is reduced .

In the fuel cell system and electrical equipment having the above configuration, for example, by the operator in accordance with the power consumption of the electric device selects the energy-saving mode, the fuel supply amount supplied to the fuel cell is changed, the required power An amount of fuel corresponding to is supplied. Therefore, fuel is not consumed unnecessarily, the power generation time is prolonged, and the operation time of the electric device is extended. At the same time, useless energy consumption is suppressed.

  Further, according to the present invention, it is possible to supply fuel corresponding to the power consumption by switching the operation mode, and it is possible to suppress the consumption of fuel and extend the power generation time of the fuel cell. In addition, suppressing fuel consumption reduces unnecessary energy consumption, which is also beneficial in terms of environmental load.

  Hereinafter, a fuel cell system and an electric device to which the present invention is applied will be described in detail with reference to the drawings based on an application example to a notebook personal computer which is a portable electric device.

  As shown in FIG. 1, the notebook personal computer incorporates a computer main body 1 having an input key and an input pad on the upper surface and a liquid crystal panel for screen display, and can be opened and closed with respect to the computer main body 1. And a display unit 2.

  The computer main unit 1 includes a drive power supply system that supplies power for performing arithmetic processing by the CPU and screen display on the liquid crystal panel. In this example, the drive power supply system using a fuel cell as a power generation unit is provided. It has been incorporated. For example, as shown in FIG. 1, a drive power supply system using a fuel cell as a power generation unit includes a fuel cell 3 that is a power generation unit, a fuel supply tank 4 that stores fuel to be supplied to the fuel cell 3, a fuel circulation control of the fuel cell, It is composed of a control circuit board 6 and the like for controlling the auxiliary machines 5 and further the auxiliary machines 5 and controlling the operating state of the fuel cell 3.

  Here, the fuel cell 3 usually has a stack structure. For example, the fuel cell 3 has a solid polymer electrolyte membrane and two electrodes (a fuel side electrode and a fuel side electrode) disposed on both surfaces of the electrolyte membrane so as to sandwich the electrolyte membrane. It is configured by stacking an oxygen side electrode) and a separator serving as a partition between cells. For the electrolyte membrane, for example, a solid polymer electrolyte membrane is used in consideration of demands for high energy density, low cost, light weight, and the like. As the solid polymer electrolyte membrane, for example, a sulfonic acid-based solid polymer electrolyte membrane or the like is used. For example, an electrode on which a catalyst for promoting a power generation reaction is supported is used as the electrode.

  The electrolyte membrane is sandwiched between electrodes, and a joined body composed of the electrolyte membrane and the electrode is sandwiched between two separators to constitute a power generation cell (unit element). Among these electrodes, hydrogen or methanol as fuel is supplied to the fuel side electrode, and the supplied hydrogen (methanol) is dissociated into hydrogen ions and electrons, the hydrogen ions pass through the electrolyte, and the electrons pass through an external circuit. Electric power is generated to move to the oxygen side electrode. Oxygen (air) as an oxidant is supplied to the oxygen side electrode, and oxygen in the supplied air reacts with the hydrogen ions and electrons to generate water.

  The fuel cell 3 may be detachable from the computer main body 1 so that it can be replaced when its characteristics deteriorate due to its life or the like. However, during normal use, the fuel cell 3 is fixed to the computer main body 1 and used as a built-in power source. .

  The fuel supply tank 4 stores the fuel supplied to the fuel cell 3 as described above. For example, when hydrogen is used as the fuel, a high-pressure hydrogen cylinder or a cartridge containing a hydrogen storage alloy is used. When methanol is used as the fuel, a container that can accommodate methanol may be used. The fuel supply tank 4 is detachable so that it can be removed from the computer main body 1 and filled with fuel.

  The auxiliary machinery 5 includes various regulators such as a regulator for adjusting the pressure of fuel supplied from the fuel supply tank 4, air supply means for sending air into the fuel cell 3, and a control valve for controlling the fuel supply amount. These actuators are configured, and these actuators are controlled by signals from the control circuit board 6. The control circuit board 6 is a circuit board on which necessary control circuits are formed, and performs operation control of the entire fuel cell system that is a drive power supply system.

  In the fuel cell system of the present invention, as shown in FIG. 1, in addition to the above, a buffer tank 7 for temporarily storing fuel is provided. Hereinafter, the function of the buffer tank 7 will be described.

  The buffer tank 7 is provided in the vicinity of the fuel supply tank 4 mounting position in the fuel supply path from the fuel supply tank 4 to the fuel cell 3. FIG. 2 shows a schematic configuration of a fuel supply system to the fuel cell 3. In this fuel supply system, the main fuel supply line is the fuel cell 3, the fuel supply tank 4 that supplies fuel to the fuel cell 3, and the fuel supply pipe 11 that connects the fuel supply tank 4 and the fuel cell 3. A branch pipe 12 is provided branching from the fuel supply pipe 11, and the buffer tank 7 is attached to the branch pipe 12. Note that a direct methanol fuel cell system using methanol as a fuel has a mixing tank for mixing methanol and water in the system, and can be used as a buffer tank.

  A control valve 13 for controlling the fuel supply by the fuel supply pipe 11 is provided on the downstream side of the position where the branch pipe 12 of the fuel supply pipe 11 is branched, and the buffer pipe 7 is opened and closed in the branch pipe 12. A control valve 14 for performing the above is provided. Information relating to the presence or absence of fuel in the fuel supply tank 4 is input to the computer main body 1, and the control valve 13 and the control valve 14 are controlled via the control circuit board 6 based on the information.

  The computer main unit 1 includes an alarm mechanism 15 that issues an alarm when the fuel in the fuel supply tank 4 becomes empty, and a remaining amount display mechanism 16 that displays the remaining amount of fuel in the fuel supply tank 4 and the buffer tank 7. Is provided.

  Here, the alarm mechanism 15 is to be surely informed to the worker, and examples thereof include sound, flashing display on the display, and a combination thereof. Further, as a specific mechanism of the alarm mechanism 15, for example, when hydrogen is used as the fuel, a change in the internal pressure of the fuel supply tank 4 is sensed, and the hydrogen pressure in the fuel supply tank 4 becomes a predetermined installation value or less. An alarm should be issued at. When methanol is used as the fuel, a drop in the liquid level may be detected by a displacement sensor or the like, and an alarm may be issued when the liquid level falls below a predetermined level.

  The remaining amount display mechanism 16 displays according to the power consumption of an electric device (notebook personal computer) based on the amount of electric power that can be generated calculated from the fuel capacity (remaining amount) in the fuel supply tank 4 and the buffer tank 7. The remaining amount is displayed on part 2. For example, when hydrogen is used as the fuel, the remaining amount of fuel is detected based on a change in the internal pressure of the fuel supply tank 4, and the remaining amount is displayed. After switching to the buffer tank 7, the remaining amount is displayed based on the remaining amount of fuel in the buffer tank 7. These remaining amounts are displayed by displaying them on the display unit 2. When methanol is used as the fuel, the remaining amount of methanol in the fuel supply tank 4 and the buffer tank 7 is detected by detecting the remaining amount based on the change in the water level by a displacement sensor and displaying it on the display unit 2.

  In the fuel supply system configured as described above, when the fuel supply tank 4 is inserted into the electric device (computer main body 1) and attached, first, the buffer tank 7 is filled with fuel. That is, when the fuel supply tank 4 is installed, the control valves 13 and 14 are operated by a signal from the control circuit board 6 so that the control valve 13 is closed and the control valve 14 is opened. A part of the fuel is transferred to the buffer tank 7.

  While the fuel is in the fuel supply tank 4, the control valve 13 is opened, the control valve 14 is closed, and the fuel in the fuel supply tank 4 is supplied to the fuel cell 3 through the fuel supply pipe 11. When the fuel in the fuel supply tank 4 becomes empty, the control valve 14 is opened to switch to the buffer tank 7. That is, the fuel in the buffer tank 7 is supplied to the fuel cell 3 through the branch pipe 12 and the fuel supply pipe 11.

  Therefore, even if the fuel in the fuel supply tank 4 becomes empty, the fuel does not run out (battery runs out) immediately. Further, when switching to the buffer tank 7, an alarm is issued from the alarm mechanism 15, and further, the remaining amount display based on the remaining amount of fuel in the buffer tank 7 is performed by the remaining amount display mechanism 16. The worker can accurately and accurately grasp the remaining battery level, and the worker can work with peace of mind.

  The notebook personal computer of this embodiment includes the buffer tank 7, the alarm mechanism 15, and the remaining amount display mechanism 16, and the operation mode of the fuel cell 3 can be switched. The operation mode is switched in accordance with the use status of), and the amount of fuel supplied to the fuel cell is changed corresponding to the operation mode. Hereinafter, this operation mode switching will be described.

  Normally, in this type of fuel cell system, in order to obtain the maximum output, the fuel cell 3 is operated under a certain optimum condition with the fuel supply amount (methanol concentration in the direct methanol system), and the necessary electric power is taken out to obtain the electric equipment. Is operating. In this case, the fuel supply amount in the fuel cell 3 is constant regardless of fluctuations in the power consumption of the electrical equipment, so that the fuel is wasted in particular when the power consumption is low. Therefore, in the present embodiment, two types of operation modes, an energy saving mode and a high output mode, can be selected according to the usage state of the electric device, thereby eliminating unnecessary fuel consumption.

  Specifically, in an electric device (notebook personal computer) equipped with the fuel cell 3, the output of the fuel cell 3 is compared with the power consumption during operation of the electric device, and the usage rate is equal to or less than a predetermined ratio. In addition, the operator is informed that the operation is possible in the “energy saving mode” by displaying it on the display. The notebook personal computer is provided with a mode select switch (not shown), and when the operator recognizes that it can operate in the “energy saving mode”, he / she operates the mode select switch. It is possible to switch the operation mode to the energy saving mode.

  When the operator operates the mode select switch to select the energy saving mode, a control signal is output from the computer main unit 1 so that the supply amount of hydrogen or oxygen (air) as fuel in the control circuit board 6 is reduced. 5 and the control valve 13 are controlled. In the direct methanol fuel cell system, the auxiliary machine 5 controls the mixing ratio of water and methanol so as to reduce the methanol concentration in the aqueous methanol solution. The operation in the high power mode is the opposite.

  As mentioned above, although specific embodiment of this invention was described, it cannot be overemphasized that this invention is not restricted to these embodiment, A various change is possible in the range which does not deviate from the summary of this invention. For example, each embodiment is an example applied to a notebook personal computer as an electric device, but can be applied to various electric devices.

It is a schematic perspective view showing an example of a notebook personal computer to which the present invention is applied. It is a block diagram which shows schematic structure of a fuel supply system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Computer main-body part 2 Display part 3 Fuel cell 4 Fuel supply cartridge 5 Auxiliary machinery 6 Control circuit board 7 Buffer tank 13, 14 Control valve 15 Alarm mechanism 16 Remaining capacity display mechanism

Claims (7)

In a direct methanol fuel cell system comprising a fuel cell and a fuel supply tank for supplying fuel to the fuel cell,
According to the power consumption of the electrical equipment , notify the user that it can be operated in the energy saving mode ,
A fuel cell system that reduces the concentration of an aqueous methanol solution supplied to the fuel cell when a signal is input to select the energy saving mode . The fuel cell system according to claim 1 , wherein the energy saving mode and the high output mode can be selected according to the power consumption . And a buffer tank to which a part of the fuel in the fuel supply tank is supplied, and the fuel tank is switched so that fuel is supplied from the buffer tank to the fuel cell when the fuel in the fuel supply tank becomes empty. 2. The fuel cell system according to 1. In an electrical device comprising a fuel cell and a direct methanol fuel cell system having a fuel supply tank for supplying fuel to the fuel cell ,
According to your own power consumption , notify the user that you can drive in the energy saving mode ,
The electric device for reducing the concentration of the aqueous methanol solution supplied to the fuel cell when a signal input for selecting the energy saving mode is received . The electric device according to claim 4 , wherein the energy saving mode and the high output mode can be selected according to the power consumption . A display for displaying that it is possible to operate in the energy saving mode;
Further electrical equipment according to claim 5, and a mode selection switch for selecting the energy saving mode. And a buffer tank to which a part of the fuel in the fuel supply tank is supplied, and the fuel tank is switched so that fuel is supplied from the buffer tank to the fuel cell when the fuel in the fuel supply tank becomes empty. 4. The electric device according to 4 .

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