JP4528048B2 - Fuel cell remaining time calculation device and fuel cell remaining time display device - Google Patents

Description

  The present invention relates to a fuel cell remaining time calculation device and a fuel cell remaining time display device, and more particularly to a fuel cell remaining time calculation device and a display device in a fuel cell mounted portable device using a fuel cell as a drive source.

  There are various types of fuel cells, but a direct methanol fuel cell is known that uses methanol, which is a liquid fuel, as a fuel, and receives the supply of methanol to generate electric power through an electrochemical reaction. The battery is called a DMFC (Direct Methanol Fuel Cell) fuel cell, which uses methanol to obtain energy based on a chemical reaction between hydrogen and oxygen.

  In recent years, the number of portable devices such as mobile phones and mobile AV devices has increased dramatically, and further demand is expected to be increased in the future. As power sources for these portable devices, so-called rechargeable secondary batteries such as lead batteries, Li-ion batteries, Ni / Cd batteries, and Ni / hydrogen batteries have been used. These portable devices are often used where there is no charging facility, and once the secondary battery is used up, there is a problem that it cannot be used.

  At present, vehicles equipped with fuel cells as a power source are entering the stage of practical use even in automobiles using gasoline chemical reaction. In the case of a fuel cell used in such an automobile, when measuring the remaining amount of the fuel tank, a flow meter provided in the fuel pipe, and an input device for inputting an initial value of the fuel to be introduced into the fuel tank, An arithmetic circuit for calculating the remaining amount of fuel by subtracting the fuel amount measured by the flow meter from the initial value of the fuel input by the input device, and a display for displaying the remaining fuel amount output from the arithmetic circuit A remaining amount measuring device is described (for example, see Patent Document 1). The flow meter 3 includes a vortex generator provided in the middle of the fuel pipe, and pressure sensors 32 and 33 that measure a pressure difference ΔP between the upstream static pressure and the downstream static pressure of the vortex generator. Based on the difference ΔP, the fuel flow rate Q flowing in the fuel pipe is calculated. According to the technique described in Patent Document 1, the fuel amount Q can be obtained based on the flow of fluid with respect to the fuel.

Japanese Patent Laid-Open No. 11-230813

  In the above technique, the current fuel remaining amount is obtained by subtracting the fuel flow rate Q obtained based on the pressure difference of the fluid from the initial value. This method can determine the remaining amount of fuel with relatively high accuracy in the case of a stationary device in which the flow of fluid as fuel is constantly stable. However, the above method has the following problems.

  First, when applied to a portable device such as a mobile device, the use of the device in the upside down state, its direction and inclination change greatly, and the position of the container filled with the methanol solution also changes greatly. Become. When used in such a use environment, an error in the theory itself based on fluid dynamics becomes large, and an accurate remaining fuel amount cannot be obtained. Secondly, when considering application to a mobile device in which the problem of the remaining amount of fuel becomes apparent, the above method based on the flow rate of fuel cannot be applied.

  It is an object of the present invention to provide a technique for accurately obtaining the remaining amount of fuel in a device that is highly likely to be used in the different environments as described above and a device that is highly movable such as a portable device. To do.

  According to one aspect of the present invention, there is provided a remaining time calculation circuit for a fuel cell, comprising: a fuel container that contains fuel; and a fuel cell body that supplies power to a drive target using the fuel contained in the fuel container. The fuel utilization efficiency is obtained based on the electric power output to the drive target within a certain period and the amount of the fuel that has flowed out of the fuel container within the certain period. There is provided a fuel cell remaining time calculating device that calculates a drivable time during which the drive target can be driven by the remaining fuel amount based on the current remaining fuel amount obtained from the amount of the fuel.

  According to the fuel cell remaining time calculation device, the power supplied to the actual load is measured within a certain period, and the fuel utilization efficiency within a certain period obtained based on the measured power is obtained. Since the remaining usable period for the fuel cell is calculated on the assumption that the fuel utilization efficiency within the certain period is substantially constant throughout the entire period, the remaining usable period corresponding to the situation can be obtained with high accuracy. .

  Furthermore, it has an environment monitor for detecting a change in the usage environment that affects the fuel utilization efficiency of the fuel cell. A new fuel utilization efficiency is obtained when an environmental change outside the normal operating temperature range is detected by the environmental monitor. As a result, the remaining time of the fuel cell can be obtained with high accuracy in response to a new environmental change.

  According to the present invention, since the power supplied to the actual load is measured and the remaining time of the fuel cell is calculated based on the fuel utilization efficiency determined based on the measured power, the remaining time can be obtained with high accuracy. In addition, by having an environmental monitor that detects changes in the usage environment that affect the consumption efficiency of the fuel cell, a new fuel usage efficiency can be obtained when an environmental change that is outside the normal operating temperature range is detected by the environmental monitor. The remaining time of the fuel can be obtained with high accuracy by adapting to new environmental changes.

  In this specification, the remaining time of the fuel cell refers to a time estimated to be usable at a certain time. Instead of the remaining time, for example, a method of displaying a percentage from the time when the fuel is fully filled may be displayed. The fuel cell remaining time display device according to the first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram showing a configuration example of a fuel cell remaining time display device according to the present embodiment. As shown in FIG. 1, a fuel cell A equipped with a fuel cell remaining time display device according to the present embodiment includes a fuel cell main body 1, a fuel container 3, and a flow meter for calculating a change ΔQ in the fuel amount Q of the fuel. 5, a wattmeter (P) 7 for measuring the power flowing through the load 21 of the device driven by the fuel cell, an initial fuel input unit (Q) 11, a remaining time calculation unit (t) 15, and a remaining time display Part 17. In this fuel cell A, the amount of fuel flowing out from the fuel container and the output power are sampled in real time or at certain time intervals, and the remaining time is calculated by performing the following calculation (here, it can be used in the future). The possible time T) is obtained.

The remaining amount of fuel (Q (t)) at a certain time is Q (t) = (Qo− （ ₀ ^t ΔQ (t) · dt), and α (t) where α (t) is the fuel utilization efficiency. ∝ΔP (t) / ΔQ (t), and the remaining time T is expressed by equation (1).

    T∝Q (t) * α (t) (1)

  Here, a predetermined amount Qo of fuel is put into the fuel container 3. A fuel flow meter measures the amount of fuel ΔQ (t) used for a predetermined time by the flow meter 5. In addition, the power output from the fuel cell at this fixed time (ΔP (t)) is obtained by the wattmeter 7. ΔP (t) / ΔQ (t), which is a value corresponding to the fuel utilization efficiency, is different for each sampling because ΔP (t) and ΔQ (t) take different values when different processing is performed. There is a possibility, but if the same equipment is used, it is assumed that ΔP (t) / ΔQ (t), which is a value corresponding to the fuel utilization efficiency in a short time, is almost constant. You can do it. By multiplying this by the remaining amount of fuel (Q (t)) when t has elapsed from the initial time point, the operable time of the fuel cell can be estimated by calculation. That is, the remaining operating time T in the current operation mode can be calculated from the equation (1) using ΔP (t), ΔQ (t), and Q (t) as parameters. This is displayed on the remaining time display unit 17. Or you may make it display the ratio of the time which can operate | move with an initial fuel, and remaining time.

  The input of (Qo) in the initial fuel amount input unit 11 is output to the arithmetic unit 15 by, for example, writing the fuel amount from the fuel supply stand on a magnetic card or IC card and reading the value based on this writing from the card. Alternatively, manual input may be performed.

  As described above, according to the fuel cell remaining time display device according to the present embodiment, the operable time based on the remaining fuel amount based on the conversion efficiency of the fuel consumption up to the time when a certain time has elapsed from the initial fuel amount. Therefore, it is possible to estimate the remaining usable time that is more suitable for the actual use situation.

  Next, a fuel cell remaining time display device according to a modification of the first embodiment of the present invention will be described. In the fuel cell remaining time display device according to the first embodiment, the remaining fuel time from the time t has elapsed based on the conversion efficiency of the fuel into electric power up to the time when a certain period t has elapsed since the introduction of the initial fuel. It is characterized by calculating the operable time based on the above. On the other hand, in the fuel cell remaining time display device according to the present modification, the current remaining fuel amount Q1 at a certain point different from the initial fuel introduction amount is obtained, and the following equation (2) is obtained based on this Q1 value. Based on the above, the operable time T can be calculated.

  If the fuel utilization efficiency is α1 (t), α1 (t) (ΔP1 (t) / ΔQ1 (t), and the remaining time T is expressed by the following equation (2).

  T∝Q1 * α1 (t) (2)

  Here, ΔP1 (t) is the output power amount at a certain time t1, ΔQ1 (t) is the fuel consumption at t1 (corresponding to the amount of fuel flowing out of the fuel cell container), and Q1 is , The remaining amount of fuel at the beginning of t1. According to equation (2), even if the amount of fuel initially introduced is unknown, for example, by using Q1 based on a fuel remaining amount meter or the like, the remaining usable time corresponding to the use environment at any given time can be obtained. There is an advantage that it can be obtained with high accuracy.

  Next, a fuel cell remaining time display device according to a second modification of the first embodiment of the present invention will be described. The fuel cell remaining time display device according to this modification is characterized in that sampling (calculation) of (ΔP1 / ΔQ1) in equation (2) is performed in a plurality of time zones. As described above, ΔP1 (t) / ΔQ1 (t) does not change so much if the devices are the same, but is likely to change if the use environment is different. Therefore, it is possible to estimate the remaining fuel time with higher accuracy based on the average fuel consumption in a plurality of time zones. Alternatively, the accuracy of estimation of the remaining time that can be operated can be improved by placing more emphasis on the utilization efficiency based on the latest fuel consumption (by performing large weighting).

  Next, a fuel cell remaining time display device according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a functional block diagram showing one configuration of the fuel cell remaining time display device according to the present embodiment. The fuel cell remaining time display device shown in FIG. 2 has an environment monitor 23 in addition to the device shown in FIG. The environmental monitor refers to a means for measuring an environment that affects the consumption efficiency of the fuel cell. For example, a temperature monitor will be described as an example. The temperature monitor 23 is a monitor that measures the temperature around the fuel cell in the device, and has a function of improving the calculation accuracy in the calculation unit 15. In the present embodiment, a temperature monitor will be described as an example of the monitor. The temperature is also detected in real time by the monitor 23 in real time. When the temperature is within a certain range, for example, within the normal use temperature range between 20 ° C. and 30 ° C., the fuel utilization efficiency (Δi) obtained from the initial fuel Q based on the above equation (1). Based on / ΔQ) / Δt) and the current fuel amount, a usable time by the remaining fuel is calculated. On the other hand, when a change to a temperature higher or lower than the normal use temperature range is detected by the temperature monitor, a new fuel utilization efficiency by a method similar to the above method is increased according to the temperature. Ask. Based on the new fuel utilization efficiency ΔP (t) ′ / ΔQ (t) ′ and the remaining amount of fuel at that time, the usable time in a new environment (temperature condition) can be obtained.

  Further, when the temperature monitor detects a change in temperature, the fuel utilization efficiency at the newly detected temperature is obtained, and the usable time at the newly detected temperature is obtained until the next temperature change is detected. be able to. In this way, each time a new temperature change is detected, the fuel use efficiency under the temperature condition is obtained in the same manner as in the method according to the first embodiment, so that an accurate usable period can be estimated. . In particular, when used for mobile devices, the environment often changes, so it is convenient to use it especially in such cases.

  In the present embodiment, a technique for calculating a usable period that changes according to a change in the environment by using a temperature monitor and performing an accurate prediction has been described as an example. As a possible environment monitor, a humidity monitor and an atmospheric pressure monitor may be used independently or in combination. It should be noted that the relationship between the measured value by the environmental monitor such as the temperature monitor and the fuel consumption efficiency can be theoretically obtained, or a calibration curve obtained empirically can be stored and used. You may obtain | require a deviation and correct | amend the calculated value of usable time in the direction which approaches a calibration curve or a theoretical value.

  Next, an electronic device according to a third embodiment of the present invention, which is an electronic device using the fuel cell remaining time display device according to the first embodiment or the second embodiment, is referred to. While explaining. FIG. 3 is an overview diagram showing a configuration example of an electronic device according to the present embodiment, which uses the fuel cell remaining time display device according to each of the above embodiments, and FIG. 4 is an internal view of the electronic device. It is a functional block diagram which shows a structural example. As shown in FIG. 3, the electronic apparatus according to the present embodiment is, for example, a portable personal computer (hereinafter referred to as “PC”) that can be carried. The PC 51 according to the present embodiment includes a device main body 81 and a lid 83 that is disposed at a position facing the device main body 81 and configured to be openable and closable with respect to the device main body 81. The lid portion 83 is provided with an LCD display portion 85. The main body 81 includes a PC power button 53, a keyboard 87, an open / close detection switch 58b of the lid 83, and a housing 75 for housing the fuel cell 52, when the fuel cell 52 is inserted. And an accommodating portion 75 having an interface portion 72 that forms an interface between the PC and the fuel cell 52. The fuel cell 52 is provided with a temperature sensor 54 for monitoring the ambient temperature of the fuel cell.

  FIG. 4 is a diagram showing a configuration example of the PC and the fuel cell shown in FIG. The fuel cell has the fuel cell remaining time display device shown in FIG. 1 or FIG. As shown in FIG. 4, the fuel cell-mounted PC 51 according to the present embodiment includes a device main body 81, a fuel cell 52, and a power operation switch 53 for the device. The power output from the fuel cell 52 to the power supply circuit 107 of the PC 51 can be detected by, for example, a power meter provided in the PC 51. The power operation switch in the PC 51 turns on the power operation switch 53 of the PC via the power circuit 107. When the power operation switch 53 of the PC is turned on, the power from the fuel cell 52 passes through the power circuit 107 and the various circuits 106 (PC circuits 106a) of the PC. And the liquid crystal circuit 106b and the other circuit 106c). Between the fuel cell 52 and the power supply circuit 107, a wattmeter 105 for detecting electric power supplied from the fuel cell is provided. Based on the power detected by the wattmeter 105, a calculation unit 111 that performs a calculation for obtaining the remaining usable time by the method according to the first embodiment or the second embodiment, and the calculation unit 111 A display control unit 113 for displaying the usable time on the LCD display unit 85 is provided. Furthermore, it has the correction | amendment process part 113a which performs the correction | amendment based on the calculation of the usable time based on temperature based on the temperature sensor 54 provided in the fuel cell 52.

  According to the PC, the remaining time of the fuel cell can be obtained with high accuracy, and the available time can be displayed based on this. In addition, about a structure, it can estimate easily that a flow meter, a fuel cell main body, a sensor, etc. are stored in an apparatus main body, and only a fuel container is made into an exchange system.

  As mentioned above, although each embodiment of this invention was described, it cannot be overemphasized that this invention is not restrict | limited by the said embodiment. In each of the above embodiments, the portable electronic device has been described. Needless to say, the present invention can also be applied to an electronic device such as a stationary liquid crystal television. For example, the fuel utilization efficiency is obtained based on the wattmeter and the amount of fuel used, but may be obtained from the current or voltage.

  Needless to say, the present invention can be applied to other electronic devices other than the PC. For example, the present invention can be applied to portable terminals (including PDAs and mobile phones), portable CD / MD players, mobile liquid crystal televisions, and the like.

It is a functional block diagram which shows the structural example of the fuel cell remaining time display apparatus by the 1st Embodiment of this invention. A fuel cell remaining time display device according to a second embodiment of the present invention will be described with reference to the drawings. An electronic apparatus according to a third embodiment of the present invention, which is an electronic apparatus using the fuel cell remaining time display device according to the first embodiment or the second embodiment, will be described with reference to the drawings. Do. It is a figure which shows the structural example of PC shown in FIG. 3, and a fuel cell.

Explanation of symbols

A ... Fuel cell, 1 ... Fuel cell body, 3 ... Fuel container, 5 ... Flow meter,
DESCRIPTION OF SYMBOLS 7 ... Wattmeter, 8 ... Timer, 11 ... Initial fuel input part, 15 ... Calculation part, 17 ... Remaining time display part, 21 ... Load, 23 ... Environmental monitor.

Claims (10)

A fuel cell remaining time calculation circuit having a fuel container for storing liquid fuel and a fuel cell main body for supplying electric power to a driven object by the fuel stored in the fuel container,
Based on the electric power output within a certain period to the drive object and the utilization efficiency based on average fuel consumption or the utilization efficiency based on the latest fuel consumption, the fuel container leaked within the certain period determine the amount of fuel, the remaining time calculating device for a fuel cell for calculating the driving target can be driven drivable time by fuel remaining amount based on the current fuel quantity determined from the amount of the spilled fuel.   The time for which the drive target can be operated is calculated by multiplying the fuel utilization efficiency within the certain period by the remaining amount of fuel after the certain period has elapsed. Fuel cell remaining time calculation device. The remaining time calculation device according to claim 1, wherein the certain period is a period that starts from a point in time when fuel is introduced into the fuel container . 3. The fuel cell remaining time calculation device according to claim 1, wherein the certain period is a period that starts from a point in time when a certain amount of time has elapsed from the time when the fuel is introduced into the fuel container .   5. The fuel cell remaining time calculation device according to claim 1, wherein the calculation is performed in a plurality of time zones. 6. Furthermore, fuel cell remaining time calculation apparatus according to any one of claims 1 to 5, characterized in that it comprises an environmental monitor to detect environmental changes affecting the fuel efficiency of the fuel cell. 7. The fuel cell remaining time calculation device according to claim 6 , wherein a new fuel utilization efficiency is obtained when an environmental change deviating from a normal use environment is detected by the environmental monitor. In addition to the remaining time calculating device for a fuel cell according to any one of claims 1 to 7, the remaining time of the fuel cell characterized by comprising a display unit that displays the drivable time that is arithmetic Display device. An electronic apparatus comprising the fuel cell remaining time calculation device according to any one of claims 1 to 8 . A fuel container containing liquid fuel;
A fuel cell main body for supplying electric power to the driven object by the fuel contained in the fuel container;
A wattmeter for measuring the power output within a certain period to the drive object;
Based on the amount of power measured by the power meter and the utilization efficiency based on average fuel consumption or the utilization efficiency based on the latest fuel consumption, the amount of fuel that has flowed out of the fuel container within the certain period A flow meter to measure,
A calculator for calculating a drivable time to drive the drive object by the fuel quantity based on the current fuel quantity determined from the amount of fuel which has the outflow,
A fuel cell with a fuel cell remaining time calculation function.

Images