JP2004229482A - Electric vehicle using solar cell as power supply for charging - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric vehicle with requiring no charging operation by having a solar cell. <P>SOLUTION: In the vehicle wherein driving time during daytime is shorter and receiving time of solar light is longer, an electric double layer capacitor is charged at driving by a battery mounted on the vehicle through a stepup circuit, then a load motor driving circuit is controlled by energy of the electric double layer capacitor to drive the vehicle. The electric double layer capacitor is charged by the solar cell installed on the vehicle when stopped. When a voltage of the electric double layer capacitor is a predetermined voltage or more, the battery is constituted to be charged through a stepdown charging circuit, by which the charging operation by commercial power supply is not required and the electric vehicle does not need the charging operation. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0101]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric vehicle that can be used as an assisting force for all or a part of a driving force by an electric motor such as a welfare electric vehicle or an electric assist bicycle that is used for a short daytime running time and a long resting time. .
[0092]
2. Description of the Related Art A conventional electric vehicle is charged with a battery from a commercial power supply via a charger.
In this case, it is necessary to separately prepare a charger at a place where a commercial power supply is present and a charger.
In the case of an electric vehicle, such a restriction is not preferable from the viewpoint of reducing the battery capacity as a driving source and reducing the weight, and it is necessary to move the battery to a place where a commercial power source is present. There is a problem that the charging work becomes painful from the beginning, and that the user must always drive while paying attention to the remaining amount of the battery.
[0056]
SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and an object of the present invention is to provide an electric vehicle without charging work.
[0086]
According to the present invention, the output of a solar cell module (5) provided in an electric vehicle is stored in an electric double layer capacitor (3), and the voltage of the electric double layer capacitor (3) is set to a predetermined voltage value. An electric vehicle according to any of the preceding claims, wherein the battery (1) is charged via a step-down circuit.
An electric vehicle characterized in that a number of spherical silicon micro solar cells are connected in series and parallel and applied as a solar cell module (5).
[0098]
Embodiments of the present invention will be described below.
FIG. 1 shows a basic configuration diagram of the power supply unit of the present invention. In FIG. 1, when the drive motor runs in power, the energy of the battery (1) is stored in the electric double layer capacitor via the booster circuit (2). Power is supplied from the electric double layer capacitor (3) to the load motor drive circuit (6), and the motor is driven.
Here, the boosting ratio of the boosting circuit (2) may be 1 to several times, but it is necessary to have a current limiting function, whereby the battery capacity can be reduced and the battery life is prolonged. When traveling downhill, it is necessary to suppress an increase in traveling speed due to a brake operation. Since the load motor drive circuit (6) of the present invention has a regenerative braking control function, braking energy is stored in the electric double layer capacitor (3) during braking operation control.
Here, the voltage of the electric double layer capacitor (3) rises due to the braking energy, but when the voltage exceeds a set value, the step-down circuit (4) operates to charge the driving battery (1). It operates to transfer the energy stored in the electric double layer capacitor (3), suppress the voltage rise of the electric double layer capacitor (3), and store the absorbed energy in the battery (1).
The running torque of the vehicle is required to be 5 to several tens times that at the time of starting acceleration and at the time of climbing a hill. A battery with a large overload capacity is required.
However, as shown in FIG. 1, the provision of the electric double layer capacitor (3) allows the transfer of a large current to and from the load by the electric double layer capacitor (3). As a result, the current capacity of the battery (1) is reduced. As long as the average current during the uphill traveling can be supplied, general-purpose products can be used and the cost is low.
Although the vehicle can be driven by the basic operation as described above, vehicles such as a welfare vehicle and an electric assist bicycle are used within a traveling distance of several kilometers to 10 km / day, and a usage time of 1 H / day. Generally, it is mainly used in fine weather.
This means that most of the time when the sun is out is not used. Therefore, if the battery is slowly charged over a long period of time using this unused time, the charge power source dose can be reduced, and the burden on the battery can be reduced, and the life can be extended.
Table 1 shows the power consumption of the battery when the electric assist bicycle travels in the standard traveling pattern (5 km). From this table, since the power consumption of the electric assist bicycle is about 10 W · H, if it takes several hours to charge, it is only necessary to have a charging power source of several W.
By using this charging power source as a solar cell installed in a vehicle, charging can be performed at any time when the sun is out. In addition, since the vehicle can be charged simply by leaving the vehicle in a state where sunlight can be received without removing and moving the battery, there is an advantage that even a person who is unfamiliar with the handling of electricity can handle the battery without any difficulty.
FIG. 2 shows an example in which a solar battery is installed on a bicycle. In this example, the bicycle tire cover (11), the frame (12), the battery unit case (13), the lower part of the rear carrier (14), and the basket (19) are provided with covers to prevent the solar cells from being damaged even when the bicycle falls. It is installed at the center of the frame as shown in FIG.
It is common to use a thin film solar cell in the form of a film. In the present invention, a spherical silicon micro solar cell is connected in series and parallel to a space of 2,350 to obtain an output of 25 V and 7 to 13 W. Can be done. Therefore, in this example, charging is completed in about one hour.
The spherical micro solar cell is a silicon single crystal having a diameter of 1 to 2 mm and its light receiving surface covers almost the entire spherical surface, so that ambient light can be captured in three dimensions, and a single-sided light receiving type conventional solar cell having the same diameter. As a result, 4 times the optical input can be taken in theoretically, and as a result, a large output can be obtained. In addition, the cell shape is small and spherical, and the mechanical strength is strong. It can be installed in parts and is suitable for vehicle installation.
In the solar cell module (5) to which the spherical micro solar cell is applied, the output obtained by receiving sunlight charges the electric double layer capacitor (3). While the electric vehicle is traveling, the voltage of the electric double layer capacitor (3) does not increase due to charging from the solar cell module (5), but the voltage of the electric double layer capacitor increases due to charging when the vehicle is stopped. When the voltage of the electric double layer capacitor becomes equal to or higher than a preset first voltage value, the booster circuit stops operating, and when the voltage further increases and reaches the second set voltage, the step-down circuit (4) operates, The battery (1) is charged with the energy stored in the double-layer capacitor (3).
Although the above description has been mainly directed to the electric assist bicycle, the present invention can be applied to an electric vehicle such as a welfare electric vehicle which has a short running time in the daytime and a long charging time.
[0242]
According to the present invention, since the electric vehicle is provided with a solar cell, it can be charged anywhere when the sun is out. This means that the conventional model can be used in a place where there is no charging facility, which is not used because the place where charging is possible is limited. For example, it can be used like park and ride from a station to work or school.
In addition, even if the battery capacity becomes empty, the battery can be charged if sunlight can be received. Can be reduced in size, and its usage is drastically changed because of its smaller size, lighter weight, and less charging work. As a result, the number of vehicles used can be significantly increased, and the environment can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a basic configuration of the present invention.
FIG. 2 is an example of an electric assist bicycle on which the solar cell of the present invention is mounted.
FIG. 3 is an example in which the solar cell of the present invention is installed on a tire cover.
Table 1 shows the power consumption when the electric assist bicycle runs on the standard pattern road.
[Explanation of symbols]

Claims (2)

The output of the solar cell module (5) provided in the electric vehicle is temporarily stored in the electric double layer capacitor (3). An electric vehicle characterized by charging a battery (1). An electric vehicle, wherein a spherical silicon micro solar cell is applied as the solar cell module (5) used in claim 1.

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