JPH09215224A - Portable power supply unit with battery charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve largely the life of a secondary battery, by providing a next stage secondary battery which feeds a power to its subsequent load and is charged by the output of a DC-DC converter for increasing the voltage of a secondary battery for charging to feed a power to the foregoing next stage. SOLUTION: A DC-DC converter 4 is a DC-AC-DC conversion type one which operates even when the voltage of a secondary battery 3 for charging becomes lower than the voltage of a next stage battery 9, and feeds a power to the next stage secondary battery 9 via a diode 5 both for preventing a reverse current and for controlling a voltage. Further, in the case of using the voltage of a constant-voltage secondary battery 3 as a reference voltage, when the output voltage of a comparison circuit 7 is higher than the reference voltage, after the output voltage is converted into an AC voltage via a chopper circuit, the AC voltage is lowered to the charging voltage of the ordinary secondary battery 9 by a step-down circuit to charge the battery 9 via the voltage controlling diode 5. Also, when being lower than the reference voltage, the AC voltage is increased to the charging voltage of the ordinary secondary battery 9 by a step-up circuit to charge the battery 9. As a result, a battery charging power supply capable of a long-time charging is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to manufacturing a battery power source. In particular, the present invention relates to a portable power supply system with a battery charger, which mainly includes a secondary battery that converts sunlight into electricity and stores the converted electricity.
A constant voltage type secondary battery for charging is arranged in the subsequent stage of the cell that receives sunlight and generates electricity, and the constant current type secondary battery temporarily stores electricity from the cell, and the constant current type secondary battery This is a battery power supply system in which electricity is taken from the battery to charge the next-stage constant-voltage secondary battery, and in particular, the charging time from the constant-current secondary battery to the next-stage constant-voltage secondary battery is extended. , And by supplying the charging current to the next-stage constant-voltage secondary battery even at the potential where the output voltage of the constant-current secondary battery is sufficiently smaller than the voltage of the next-stage constant-voltage battery, It is possible to extend the operating time of the load circuit connected to the constant voltage battery by prolonging the charging time in the time zone when there is no light or in the rainy day and in the rainy day, and it is possible to keep the load operating state for substantially 24 hours. Power supply system.

The technical terms used in this specification have the following meanings. The “secondary battery” refers to a battery that can be repeatedly charged and discharged. On the other hand, the term "primary battery" refers to a battery, such as a dry battery, which has its life reached by discharging electricity once stored and discharging it.

The "constant current type secondary battery" refers to a secondary battery whose current value is relatively constant even when the voltage changes up and down, and refers to a capacitor type battery such as an electric double layer battery described later. Also, "constant voltage secondary battery" is a battery whose voltage is constant but whose current can change. Normally, this type of secondary battery means lead-acid batteries, NiCd secondary batteries, lithium secondary batteries. Belongs to this.

The "electric double layer battery" is a typical constant current type secondary battery, and has a mountain-shaped voltage characteristic as shown in FIG. 2 and a current characteristic of a substantially flat type. The reason for using this to charge a constant voltage battery at high speed is described below.

Japanese call a cell for converting sunlight into electricity a "solar cell", which is incorrect. The cell has only the function of a converter that converts sunlight into electricity, and has no function of storing electricity. A storage battery is needed to store the generated electricity. Solar cells are also a technology that started by reducing the ambiguity of these words.

[0006]

^2. Description of the Related Art The sun is pouring an average of 1 m ² (1 m × 1 m) of 1 kW of energy in an area of 65 ° north and south latitude centering on the equator on the earth. To convert this energy into electricity, semiconductor single crystals have 15 to 16%, and polycrystals have 14%.
In the inside and outside, amorphous (non-crystalline) with an efficiency (conversion efficiency) of 7 to 8% is used. When these are used to illuminate a domestic light bulb (100 W), a single-cell or poly-crystal cell produces an amount of electricity that only one light bulb shines in a 1 m ² cell while the sun is being poured. Then you can't light this bulb. Comparing these in terms of cost, which is the basis of the technology, most of the single crystals are
It is made by purifying a polycrystal and then refining it through a process such as a pulling method, and its cost is higher than that of the polycrystal. Even if the conversion efficiency is increased by 1 to 2% as described above, the cost is usually more than double that of the polycrystalline cell.

On the other hand, the conversion efficiency of amorphous is only half that of polycrystalline. In the manufacturing process, there is almost no cost difference between amorphous and polycrystalline. Moreover,
Amorphous cells suffer from the disadvantage of deterioration over time, which is a characteristic that deteriorates over time. Then, in order to obtain the same performance, an area twice as large as the area of the polycrystalline cell is required. While the polycrystal having a conversion efficiency of 14% per 1 m ² described above produces electric energy of 130 to 140 W, the amorphous requires a cell plane of 2 m ^{2 which} is twice as large. That is, the costs do not match each other.

Currently, electric power for electric lights and heavy industry is 100 to 20.
It is supplied by 0V AC commercial power supply. The source is
Hydropower, coal fired power, oil fired power, LPG fired power, or nuclear power. These energy sources are very large,
It is not a small energy that can be covered by each household. At the same time, it is too dangerous to use in each home. For this reason, it is installed on a large scale in a place away from private houses such as mountains, valleys and the sea, and the voltage is increased to 100V, 200V to deliver this energy to a long distance.
The current situation is that they are sent via power lines and distributed to homes and factories. If this is not done, safety will not be maintained, legal control will not be possible, and costs will not be reduced. We call this the centralized management method, and this management method is left up to the electric power company and the country.

On the other hand, the solar cell has 1
For example, a cell of m ² has a conversion efficiency of 100%, but 100 W
Only 10 bulbs generate enough energy while the sun is shining. This is covered by power transmission and distribution in homes and factories, called power sale if necessary, with a cell on the roof or fence of the home, and having the power company buy some of the power generated during the day. Partly adopted.
However, this method is quite significant, but from a technical point of view, the cost is too high, and the energy consumption is less than 2%. Furthermore, countries like Japan that are well equipped for power transmission and distribution are rare in the world, and power transmission is completely impossible in neighboring countries such as China, Southeast Asia, and many Middle Eastern countries. Even in the place where there is no wiring on the sea or in the mountains, its life is difficult as well. Currently, the semiconductor circuits used in home appliances are 3.3V memory devices and 5. 5% driver circuit devices.
Most of them are driven by 5V, and a commercial power supply of 100V is mainly used to drive these circuits. 1
The AC voltage of 00 V is dropped and the amperage is converted to a DC power source for digital signals for use. 100V
If you use the commercial power supply of the above and drop it to the voltage / current for IC circuit of 12V or less, a) There are legal restrictions under the Electricity Business Law, and there are various restrictions on handling, and it is not allowed to tamper with it at home. .

B) If the transistor circuit is PNP-N
In the case of the PN complementary configuration, if the two do not have similar characteristics, an unbalanced current will occur in the electrodes on the switching transistor side, causing an unintended phenomenon such as a short circuit or a large current flowing that will cause a fire. It may happen. A large current flows in a power supply with a grounded transistor circuit element of PNP or NPN alone, so the power consumption is great, and sometimes the amount of this current becomes too large, and the circuit shorts or overcurrent flows to the load. This may short out.

Therefore, the most suitable power source for a transistor circuit that depends on a voltage of 20 V or less and a current of 2 A or less is to generate electricity in a solar cell and use the solar battery that stores the electricity as a power source.

More specifically, a device using a semiconductor (most of which is driven by a power source of 6 V or less) or a 12 V voltage like a car is used together with a cell. By loading a secondary battery (this secondary battery may also be used as an on-board lead battery), and a mechanism that drives it with a hybrid configuration with energy from gasoline-this is a single unit without wiring. It is called a distributed processing mechanism because it can be processed by the-, but in the case of-, the energy to move the equipment needs only a few hundredths / thousandth of the energy of the conventional centralized control system power supply, and most of it can be covered by the distributed processing mechanism power supply. Can be done. In other words, in addition to the centralized control system, the power source that is a distributed processing system and uses solar battery technology is kind to the equipment and also serves as a power source that prevents environmental damage that would not require battery replacement for years and decades. In that sense, the solar cell is a technology that can cover 90% or more of semiconductor circuit equipment for a long time with about 1% of the total energy.

As a conventional technique, there is a system in which electricity from a silicon cell is stored in a lead-acid battery for automobiles or a nickel-cadmium battery and the transistor device is operated by using this. However, in this method, (1) charging and discharging of the secondary battery is 4
Be less than 00 times. (2) In the lead storage battery electrode of the secondary battery, an insulating layer of lead sulfate (PbSO ₄ ) is formed,
Because of this, charging doesn't go as expected. Lead sulfate cannot be decomposed without strong charging. For this reason, the charge and discharge will be 200 times or less. (3) The weight becomes heavy. In the case of a lead storage battery, it will be about 8 to 10 kg for 12V. (4) Since the nickel-cadmium battery and the lithium battery have a lifespan depending on the number of times of charging and discharging, the cost becomes high.

[0014]

SUMMARY OF THE INVENTION The present invention is intended to improve the above-mentioned deficiencies and significantly improves the life of a secondary battery.
The present invention proposes a portable power supply device with a battery charger that can continuously use the existing secondary battery for almost 5 years or more continuously.

[0015]

A portable power source with a battery charger according to the present invention is a secondary battery which is charged at a high speed, such as an electric double layer battery having activated carbon as an electrode, which is provided in a subsequent stage of a cell which receives sunlight and generates power. Installed, it operates even at a voltage extremely lower than the voltage of the secondary battery of the latter stage, a DC-DC converter for temporarily boosting this voltage to supply power to the next stage is provided, and further charged by the output of the DC-DC converter, and It is characterized in that a next-stage secondary battery that supplies electric power to a latter-stage load, for example, a secondary battery such as NiCd or lithium is installed.

According to the Japan Meteorological Agency's announcement, the average daily sunshine time in one year of Japan is 3.8 hours. On the other hand, a 12V general battery, for example, a lead secondary battery, a nickel-cadmium secondary battery, or a lithium secondary battery can be charged from 1V or less at a maximum of 4 to 6 hours. This means that charging is not completed in an average day. The present invention, by taking the above means, completes the accumulation of the generated power in the cell within the first-stage secondary battery within at least one hour, and makes the storage amount (F = I × T / V) of this secondary battery effective. In order to utilize it, the primary side is operated with a voltage as small as possible, for example, within 3V, and the secondary side is raised to a voltage slightly higher than the voltage of the next-stage secondary battery, and then this power is supplied to the next-stage secondary battery. By extending the number of charge / discharge cycles of the next-stage secondary battery-usually this is called the respiration of the secondary battery- (the respiration of the ordinary secondary battery is said to be limited to 400 times, It allows more than 1000 breaths per second (by increasing the breathing time of the battery), and the life of the secondary battery is 5
It is possible to use it almost continuously for more than a year. As the secondary battery for high-speed charging at the first stage, an electric double layer battery is usually used so that the number of times of charging and discharging can be made almost infinite. However, the capacity of the electric double layer battery is about 1/10 of that of the lead storage battery at present, and the discharge rate is within 1/6 of that of the lead storage battery. Therefore, while the sunlight is shining, charging from the cell to the electric double layer battery is 3.8.
Do it within the time, charge the constant voltage battery of the next stage with the overflow current, and drive the load circuit, and slowly and gradually replenish the charging current to the next stage battery at night or in the rain when the sunlight disappears. Energy is stored in the electric double layer battery by connecting the DC-DC converter to the electric double layer battery even if the voltage of the electric double layer battery becomes lower than the potential of the constant voltage battery of the next stage. It is possible to charge the battery for a longer time by efficiently using the bottom part.

On the other hand, by digitizing the load circuit partly or wholly to reduce the circuit that normally requires a current of about 200 mA to about 1/10 of that circuit, the load can be operated all the time by averaging 20 mA. You can also

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to specific examples shown in the drawings.

In FIG. 1, reference numeral 1 is a cell for converting sunlight into electricity, and specifically, a cell having an output of 17.6V and 25W was used. 2 is a reverse current prevention diode and a voltage control diode, 3 is connected in parallel with the cell 1, and a secondary battery for high-speed charging that stores the electricity sent from the cell 1 (using an electric double layer battery)
Then, the one of 150F and 12V was used. 4 is DC-DC
In the converter, the voltage of the secondary battery for charging changes to the next-stage battery 9
DC-AC-D that operates even when the voltage becomes lower than the
C conversion was used. The reason for this is that the charging secondary battery 3 is a constant current type, a so-called capacitor type, and the voltage changes into a mountain shape as shown in FIG. 2, and in order to use almost all of the battery energy contained therein, 17 This is because electric energy in the range of 0.6V to 3V is used. D
The C-DC converter 4 supplies power to the subsequent secondary battery 9 (NiCd battery or lithium battery) via the reverse current prevention diode 5 and the voltage control diode 5. Reference numeral 6 is a DC-DC converter for protecting the electric double layer battery, and 7 and 8 are a comparison circuit in the DC-DC converter 4, which is a central configuration of the present invention, and a step circuit connected to the comparison circuit.

Reference numeral 10 is a load. (Since a DoCoMoN type telephone was used, the rear Ni-Cd battery was 6V, 900mA.
In the case of h, the waiting time period is pulse reception, and the load current is reduced from 100 mA to 10 to 20 mA. ) The capacity of the electric double layer battery used here (therefore, the internal resistance) is about 1/10 of that of a general battery (the internal resistance is 1).
Note that it is 0 times).

The reason is that the charging speed of the constant current type battery is delayed, or the charging current is supplied to the next stage constant voltage type secondary battery 9 even at a potential sufficiently smaller than the voltage of the next stage constant voltage type secondary battery. The reason is that the charging circuit can be charged even during the time when the sun light disappears or during the rainy day and the operating time of the load circuit is long.

If so, whether the electric double layer battery is useful or not is not so. First, it is necessary to charge the battery at a constant current in order to charge it. On the contrary, the constant voltage type is advantageous for discharging the battery. However, the voltage characteristic of the electric double layer is a characteristic of a capacitor known to humans, that is, a constant-current type characteristic with a downward slope as shown in FIG. So cell 2
Is set to about 15 V and stored in the electric double layer battery 3 in a short time. Therefore, the minimum output voltage of the electric double layer battery is set to about 3V. By the way, if the electric capacity of the electric double layer battery 3 is 150F,

[0023]

[Equation 1]

Within 30 minutes (24 minutes in calculation), saturation is reached, and then a current of 420 mAh is supplied to the output side.
By the way, a pure battery, for example, a 12V lead battery for an automobile is 5A
It takes about 5 hours to remove the wedge of PbSO ₄ when it is charged at 1, and 8 hours or more at 2A charging. Regarding discharge,

[0025]

[Equation 2]

It is understandable for a person who has an automobile on a daily basis that the discharge lasts for about 2.8 hours and 2A discharge takes 7 to 8 hours. As described above, it is difficult for the electric double layer battery 3 to serve as a battery by itself with the current capacity. Of course, it can be used as a battery for timepieces inside and outside 0.001A (1mA) or a part of liquid crystal products, but it is difficult for a transistor device of about 1A. Because it is like the calculation above

[0027]

(Equation 3)

This is because the battery does not work in about 25 minutes. Of course, if the sun is out, charging of 1A or more will be done, so this can be covered, but the point is the problem after sunset.

Therefore, the pure secondary battery must be taken care of. Secondary batteries such as NiCd secondary batteries are needed as main batteries. However, this secondary battery is best charged and discharged about 400 times. 1000
It seems that it can be used only once, but it does not currently exist and it does not match the cost at all. Speaking of about 400 times of charge and discharge, it will be useless within a year or at most two years. Therefore, the effective time of the secondary battery is made to be substantially long by constantly performing the charging about 400 times even if the charging power is low. For that purpose, the secondary battery 3 for high-speed charging at the first stage is an electric double layer battery, and is filled up within 30 minutes. At this time, what is important is how to discharge from the secondary battery for high-speed charging after the tank is full within a long time.

Therefore, the DC-DC converter circuit 4 of FIG.
And the DC-DC converter shown in FIG. 3 will be described in some detail.

The DC-DC converter circuit 4, the comparison circuit 7, the step circuit 8 in FIG. 1 and FIG.
FIG. 3 is a block diagram of one embodiment of charging of the next-stage NiCd constant voltage battery 9 by a discharge current from the chopper type stepping inverter circuit diagram.

As shown in FIG. 2, the capacity characteristics of the electric double layer battery are different from those of the constant voltage type secondary battery (denoted by reference numeral 9 in FIG. 1), and the constant current type secondary battery (reference numeral 3 in FIG. 1). Indicated by.)
It is a mountain-shaped voltage characteristic showing the aspect of. This is a necessary condition for battery charging. Therefore, in order to make the voltage flat like a constant voltage type secondary battery by using almost all the batteries having this voltage characteristic, the voltage at the foot of the mountain, that is, a low voltage of 2 to 3V. By stepping up the range and using it, the load can be driven sufficiently longer than the operating time of one ordinary battery. For that purpose, the reference voltage must be set.

There are the following four ways to set the reference voltage.

(1) DC-D voltage from solar cell
When using the input side voltage of the electric double layer battery when adjusting with the C converter and using it as the input of the electric double layer battery, in the case of the output of the solar cell of 17.6V, 1.4A in FIG. Assuming that the electric double layer battery has a voltage of 150 F and 11 V, the DC-DC converter output before and after that is 12
The reference voltage is 11 because it must be brought near V
V to 12V.

(2) The voltage of the electric double layer battery is set to DC-DC.
When the voltage is adjusted by the converter and is not close to the voltage of the next-stage battery, and this is used as the reference voltage, the output of the electric double layer battery is around 12V, and this is adjusted by the DC-DC converter, and the secondary battery is normally used. Near the input voltage (in this example, 7.2
V) was used as the reference voltage.

(3) When the output of the stepping inverter is used as the reference voltage, the charging input of the secondary battery is usually 10% to 20% higher than the output. In this example, it is around 7V.

(4) When the voltage of the constant voltage type secondary battery is used as a reference voltage, the constant voltage type secondary battery is 6 V, 0.9 Ah.
In the case of using the above, the reference voltage is around 6V.

Of these, the case (4) is easiest to understand, and this will be further described.

Since the output voltage of the electric double layer battery changes as described above (for example, from 12V to 0V), when the electric double layer output voltage is higher than the reference voltage by the voltage comparison circuit of this voltage and the reference voltage (6V). A comparison circuit (denoted by reference numeral 7 in FIG. 1) for distinguishing between the low case and the low case must be installed. However, when the output of the comparison circuit 7 is higher than the reference voltage, this is converted into an alternating current through the chopper circuit, and then the voltage is stepped down to the normal charging voltage (7.2 V) of the secondary battery. The ordinary secondary battery is charged through the voltage control diode.

On the other hand, when the output of the comparison circuit 7 is lower than the reference voltage, this is also converted into an alternating current through the chopper circuit, and then the voltage is stepped up to the normal secondary battery charging voltage (7.2 V). As described above, the ordinary secondary battery is charged through the voltage control diode.

When the reference voltage is set to 7.2 V, it is clear that only the step-down circuit should be connected after the comparison circuit.

FIG. 3 shows an example of a circuit when the reference voltage is an ordinary secondary battery. Reference numeral 11 in FIG. 3 is an IC including the comparison circuit 7 of FIG. 1, a step inverter (up or down or both) circuit 4, and a control circuit such as a timing circuit and an oscillation circuit. Further, FIG. 4 shows the experimental values, the dotted line 12 is the output voltage of the electric double layer battery, the hatching 13 is the recovery voltage by the chopper type step-down inverter, and the hatching 14 is the step-up obtained in the voltage region indicated by the hatching 15. Is the recovered recovery voltage.

[0043]

As described above, according to the portable power supply device with the battery charger according to the present invention, 90% or more of the semiconductor electric devices can be handled in each home by the distributed processing, and the ignition of the automobile can be prevented. It is possible to obtain a battery power source that can be charged for a long time even in a part of the power source of the carrier such as the supply of instantaneous pulse voltage and current.

[Brief description of drawings]

FIG. 1 is a block diagram of a portable power supply device with a battery charger according to the present invention.

FIG. 2 is a voltage characteristic diagram of an electric double layer battery.

FIG. 3 is a stepping circuit diagram of the DC-DC converter.

FIG. 4 is a measured value on the output side of an electric double layer battery in a 6V standard power supply of a portable power supply device with a battery charger of the present invention.

[Explanation of symbols]

1 Cell 2 Reverse Current Prevention Parallel Voltage Control Diode 3 Secondary Battery for Fast Charging 4 DC-DC Converter 5 Reverse Current Prevention Parallel Voltage Control Diode 6 DC-DC Converter 7 Comparison Circuit 8 Step Circuit 9 Secondary Battery 10 Load 11 Step Inverter and Timing IC 12 equipped with a control circuit such as a circuit and an oscillation circuit 13 Output voltage of electric double layer battery 13 Recovery voltage by chopper type step-down inverter 14 Recovery voltage by chopper type step up inverter 15 Output voltage of electric double layer battery is below reference voltage Area that became

Claims (2)

[Claims] 1. An electric double layer battery having a voltage / current characteristic of a condenser is arranged at a rear stage of a cell that receives sunlight and generates electric power, and the next-stage constant voltage type battery is charged by a current from the electric double layer battery. A secondary battery is arranged, and is connected to the output side of the electric double layer battery between the electric double layer battery and the next-stage constant voltage secondary battery, and the output of the electric double layer battery and the electric double layer. Saturated output voltage of the battery or a voltage adjusted from this, or through a comparison circuit that compares the output voltage of the next-stage constant voltage secondary battery with the reference voltage, a stepping inverter of the chopper system is installed, and A portable power supply device with a battery charger, wherein the output of the inverter is used as the input of the next-stage constant voltage secondary battery. 2. The portable power supply device with a battery charger according to claim 1, wherein the stepping inverter uses a step-up inverter, a step-down inverter, or both.