Batteries: thermoelectric and photoelectric – Applications – Circuits
Reexamination Certificate
2000-04-21
2002-02-12
Diamond, Alan (Department: 1753)
Batteries: thermoelectric and photoelectric
Applications
Circuits
C136S244000, C136S291000, C320S124000, C320S127000, C320S128000, C320S135000
Reexamination Certificate
active
06346670
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a solar battery system in which electric energy generated by a solar battery is stored in a storage battery, and the stored electric energy is supplied to a load.
BACKGROUND OF THE INVENTION
In a conventional solar battery system, a solar battery is installed at an angle of 45 to the ground in a southerly facing direction. Generally, such conventional solar battery systems comprise a storage battery, wherein the electrical output of the solar battery produced from the average duration of sunshine per one day obtained from meteorological observation data in Japan (usually about three hours) is stored in the storage battery, and the stored electric energy is used as the power source.
In such a system, during rainy or cloudy weather, the output of the solar battery is so weak that sufficient charging of the storage battery is impossible. Hence, such a conventional solar battery system is inoperable during rainy or cloudy weather. Therefore, in order to compensate for poor weather (referred to herein as “unsunniness compensation”) the capacity of a storage battery is increased, and in rainy or cloudy weather, stored electric energy is used as the power source. In such case, for example, if poor weather persists for 5 to 30 days, the capacity of the storage battery must be 5 to 30 times that of the needed daily electric power.
Such a conventional solar battery system, as described above, has been used for a long time. However, as the effective use of a conventional solar battery system at locations where power sources do not exist becomes popular, weather/environmental conditions which limit the use of solar battery systems become important factors to consider, since they pose basic problems that limit the installation of a solar battery system. For example, prior to installation many factors must be considered, such as the placement of the solar battery in a sunny location at an angle of 45° to the ground facing south, installation of a solar battery in a location that does not mar the view, and that charge and discharge operation trouble is caused by snow lying on the surface of a solar battery.
That a solar battery system is convenient and safe are important conditions in the design of same, for the spread of use of such systems. However, speaking of conditions of design, it goes without saying that a new solar battery system is desired in which the charge and discharge operation is assured even in such cases where the solar battery is placed in the shade, and/or in rainy or cloudy weather, and conditions on the installation of a solar battery outside do not matter, such as installation of a solar battery perpendicular to the ground in snowy areas.
Accordingly, a solar battery system is disclosed, for example, in Japanese patent laying-open No. 177683 of 1995 (Heisei 7), which includes a combination of an electric double layer condenser as a storage battery and a large capacity solar battery which generates a given output even under weak solar light, in the shade, in rainy weather, etc. The solar battery system can be used for long periods of time even if chargings are repeated every day regardless of weather, since the number of charging and discharging cycles of the electric double layer condenser is in the hundreds of thousands. Further, since charging is possible even in the shade and in rainy weather, the installation location of the solar battery is irrelevant. Thus, the solar battery system may be made small and inexpensive.
However, the ratio of power output of a solar battery system placed in an ideal location facing the south versus a solar battery system placed in the shade in rainy weather is generally about {fraction (1/20)}. In the case of the above two examples, in order to generate sufficient needed daily electric energy, power output of the solar battery system placed in the shade in rainy weather must be about 8 times as large as the solar battery system placed in an ideal location facing south, necessitating a large and more expensive solar battery system.
With regards to theoretical values, assuming daily needed electrical power output is 10 Wh/day, the power output of the solar battery system in all ideal location facing the south=10 Wh/3h (the average duration of sunshine per day)=3 W, while power output of the solar battery system located in the shade in rainy weather={10 Wh/8h (charging time in the daytime)}×20 ((damping correction coefficient in the shade in rainy weather)=25 W. Accordingly, a solar battery system of large-size and large-output is needed.
Further, in a solar battery system which includes a combination of a storage battery having the capacity to store the daily required electric energy and a solar battery capable of charging the storage battery even in the shade in rainy weather, the operation of the solar battery system in all weather conditions is assured. However, although the solar battery system is placed in a location facing south and is large-sized, the storage battery is quickly charged with a sufficient daily electric energy, after charging, surplus output of the solar battery remains and is released as useless energy. Therefore, such a solar battery system is inefficient and uneconomical.
Even if the capacity of the storage battery is increased to avoid the wasteful release of valuable charged energy, the output of discharged electricity is constant, which ensures charge and discharge in case of the poor weather conditions. Even if weather or installation location of the solar battery is changed, the output of discharged power is constant and cannot be increased. As a result, such a solar battery system is uneconomical and performs only simple function.
Moreover, although a conventional solar battery system has an effective face, the conventional battery system needs a wide area for the installation thereof, is large-sized and high-priced, therefore uneconomical. Further, conventional solar battery systems are designed to deliver simply a constant supply of electric power determined by the load needed to be affected, and provide merely an intermittent constant level of electric power. The output of the solar battery system, the charging state of the storage battery, the quantity of electric power needed based on load and the control of charge and discharge, were not necessarily performed and/or considered.
SUMMARY OF THE INVENTION
The present invention is provided in consideration of the above-mentioned problems, and provides that although the quantity of power charged to a storage battery changes according to the output of a solar battery, which itself depends on the state of solar radiation at the location of the installation of the solar battery, the output discharge quantity is automatically controlled in accordance with the changing charge quantity, so that effective and wise control operation of charge and discharge, and efficient utilization of solar energy without waste, is possible.
Namely, the area occupied by the solar battery system to the number of solar battery panels is decreased, and the quantity of electric power needed in case of poor weather/environmental conditions is ensured. Further, when the solar battery system of the present invention is located in a sunny place facing the south, the present invention makes use of the valuable large quantity of power output generated by a large capacity solar battery, a large quantity of electric power is charged and stored into a storage battery, and the supply of a larger quantity of electric power into a load or loads can be automatically performed.
Further, it is another object of the present invention to provide a solar battery system which stores long-term data concerning charge and discharge in memory, so that the solar battery system has reliable data to ensure long-term, stable operation and reliable-maintaining function, and has a maintenance function based on such self-learning and self-diagnostic data stored into the memory, which can be used economically and
Fujii Takashi
Namioka Hironori
Diamond Alan
Haneda Humepipe Co., Ltd.
Townsend & Banta
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