JP2000060013A - Battery charging control device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To realize an inexpensive and highly safe storage battery charge control device which is not affected by an inrush current or the like. A switch means is provided between a main battery and a sub-storage battery so that the ON resistance of the switch means gradually decreases when the switch means changes from open to closed, and the switch means opens sharply when the switch means changes from close to open. When detecting that the terminal voltage of the main storage battery has become higher than the terminal voltage of the secondary storage battery by the first set voltage and that the terminal voltage of the main storage battery has become higher than the second set voltage, the main and sub storage batteries And the terminal voltage of at least the main storage battery decreases to a voltage higher than the terminal voltage of the sub storage battery by a first set voltage or more, or the current value detected by the current detecting means is a predetermined set value. A configuration in which control is performed so as to open between the main and sub-storage batteries when it is detected that the voltage has become higher than the above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system including a plurality of storage batteries in which a main storage battery is connected to a main storage battery, and to balance all the storage batteries while giving priority to the main storage battery. It belongs to a charging technique for charging.

[0002]

2. Description of the Related Art In a vehicle equipped with a large number of retrofitted loads, such as a camper, a single storage battery cannot cover all the loads as in a general vehicle.
Therefore, normally, a secondary storage battery called a sub-battery is mounted on the user side with respect to the main storage battery.
The plurality of batteries are connected in parallel to the alternator, and the voltage of the alternator is uniformly applied to all the storage batteries during traveling. With such a configuration, even if the storage battery is fully charged, the voltage is continuously applied and the battery is likely to be in an overcharged state, and there is a problem that the storage battery is deteriorated in a short period of time. One of the causes is considered to be a refrigerator or a microwave oven as a load covered by the storage battery in a camping car.In most cases, the owner uses the storage battery for commuting on weekdays, and the storage battery is discharged. Since there is little opportunity to charge the vehicle, it is conceivable that the vehicle will be overcharged due to charging during traveling.

In order to solve such a problem, a storage battery charging control system as described in, for example, Japanese Patent Application Laid-Open No. 6-205537 has already been proposed. For example, the above-described conventional storage battery charge control system measures the voltage of a secondary second storage battery (described in the same publication) and performs overcharge protection of the second storage battery. This is a storage battery charging control system connected between a first storage battery charged by a power generation means and a second storage battery, and detects a magnitude and direction of a current flowing between the two storage batteries. Means, voltage detection means for detecting the terminal voltage of both storage batteries,
Switch means for opening and closing between the two storage batteries, and when the voltage detection means detects that the terminal voltage of the first storage battery exceeds the first set voltage and is higher than the terminal voltage of the second storage battery, the switch means Is maintained in a closed state, and the second storage battery is controlled to be charged by the power generation means, and at least the voltage detection means detects that the terminal voltage of the second storage battery has exceeded the second set voltage, or When the detection means detects that a current has flowed from the second storage battery to the first storage battery, control is performed to maintain the switch means in an open state. In addition, there are also those described in JP-A-9-70148 and JP-A-9-107639.

[0004]

These documents disclose monitoring the terminal voltage of the engine start storage battery when the engine is running and charging the additional storage battery when the voltage exceeds a specified voltage. . Further, a current detection mechanism for setting the charging current to a safe value is disclosed. However, it does not disclose what kind of problem occurs due to a difference in operating voltage between the storage batteries and what specific means can be solved by it. Further, it does not disclose what kind of problem is substantially caused by simply opening and closing the switch means between the two storage batteries. actually,
The present inventors have found that even with the overcurrent protection function, the effect of an excessive rush current flowing between two storage batteries appears as a very serious phenomenon. And it turned out that it is one of the main factors of the deterioration factor of a secondary storage battery. They also found that the charge control system itself could be destroyed. This will be described below.

[0005] First, when the voltage of the first storage battery rises to a predetermined voltage and the switch means is closed, an excessive current flowing toward the second storage battery within a short time immediately after the switch is closed. It is a current. That is, at the moment when the switch means is closed, it is expected that a large current will flow for a moment. The internal resistance of the storage battery is on the order of milliohms, and even with a small voltage difference, the flowing current becomes extremely large. Even if the overcurrent protection is applied, there is a time lag before the protection function works, and the instantaneous large current during this time may lead to destruction of the element used as the switch means. Second, there is an effect of a large current flowing from the second storage battery to the first storage battery. That is, in the charging control as described above, while monitoring the voltage of the second storage battery, when a current from the second storage battery to the first storage battery is generated due to a decrease in the voltage of the first storage battery due to lighting of a headlight or the like. The switch means is opened, but the same large current influence as described above appears due to the time lag when the switch means is opened. This is caused not only by the capacity of the alternator but also by the voltage difference between the main storage battery and the secondary storage battery, and the current value may be as short as several thousand amps for a very short time. Such a phenomenon becomes serious not only when the switching means is destroyed but also when the influence on the storage battery is considered. In addition, the circuit configuration for the avoidance measure also requires a very high-speed switching control for large overcurrent protection, resulting in a problem that the cost becomes extremely high.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to realize an inexpensive and safer battery charging control device. Such a problem occurs in a storage battery charge control device that controls charging of a main storage battery connected to a power generation unit and a sub storage battery connected to the main storage battery, and a main voltage detection device that detects a terminal voltage of the main storage battery. Means, a dependent voltage detecting means for detecting a voltage of the storage battery,
A current detecting means for detecting a current flowing from the main storage battery side to the auxiliary storage battery side, and opens and closes between the main storage and the auxiliary storage battery, and at the time of transition from open to closed, its ON resistance gradually decreases, At the time of transition, it is configured to open sharply, the terminal voltage of the main storage battery is higher than the terminal voltage of the sub storage battery by the first set voltage or more, and the terminal voltage of the main storage battery is higher than the second set voltage. The main battery and the auxiliary battery are closed when it is detected that the terminal voltage of the main battery is lower than the terminal voltage of the auxiliary battery at least by a first set voltage or more than the terminal voltage of the auxiliary battery. And a switch means for controlling to open between the main and sub storage batteries when it is detected that the current value detected by the control unit becomes higher than a predetermined set value. It can be solved by the. Here, the current detecting means includes a resistor interposed between the main and sub storage batteries and a resistor end voltage detecting means for detecting a voltage of the main and sub storage batteries on the resistance side. It is preferable that the configuration is such that the magnitude of the current flowing from the main storage battery to the sub storage battery is detected by comparing the resistance end voltage difference of the storage battery with the third set voltage.

The operation of the present invention will be described below by taking a motor vehicle such as a camper equipped with many retrofit loads as an example. A main storage battery for running the vehicle is connected to the alternator as the power generation means. A sub storage battery is connected to the main storage battery via switch means. The main storage battery supplies power to running loads such as engine starters and headlights, and the secondary storage battery supplies power to camping car dedicated loads such as refrigerators and microwave ovens. The main storage battery is charged from the alternator during traveling, and the best charge state is maintained almost always. On the other hand, the capacity of the secondary storage battery decreases as power is supplied to the above-described camping car dedicated load. At this time, the voltages of the main storage battery and the auxiliary storage battery are detected by the main voltage detection means and the auxiliary voltage detection means, respectively, and the terminal voltage of the main storage battery becomes higher than the terminal voltage of the auxiliary storage battery by the first set voltage or more. Further, when it is detected that the terminal voltage of the main storage battery is higher than the second set voltage, the main and sub storage batteries are closed (ON) and the sub storage battery is charged. That the terminal voltage of the main storage battery is higher than the terminal voltage of the sub storage battery by the first set voltage or more
This means that the charging current of the secondary storage battery can flow from the main storage battery side to the secondary storage battery side, in other words, the secondary storage battery is charged with priority given to the main storage battery for traveling. In addition to this, by detecting whether the terminal voltage of the main storage battery is higher than the second set voltage, not only the voltage difference between the two storage batteries, but also the main storage battery having the basic function of traveling is used. It can be determined whether the battery is in a state to be charged. Thus, by comparing with the two types of set voltages,
ON / O of charging current from main storage battery to secondary storage battery
FF control is performed. The switch means for performing the ON / OFF control is configured so that the ON resistance gradually decreases when the state changes from open to closed, and prevents current destruction due to an inrush current to an element or the like used for the switch means. are doing. This is because the overcurrent protection function should be added in the present invention, but if the ON resistance is not changed as described above, even if the overcurrent protection function is provided, the same function is provided. Within a very short time before
This is because there is a risk that an instantaneous excessive current flows. This time constant of the ON resistance can be realized by increasing the gate resistance, for example, when an FET is used as the switch means.

[0008] On the other hand, when the switch means is closed, the charging power from the alternator is supplied to the auxiliary storage battery, so that the capacity of the main storage battery decreases and the terminal voltage thereof decreases depending on the load of the traveling load. In this case, the switch means is opened (OFF) to charge only the main storage battery preferentially, and when the voltage of the main storage battery decreases due to some load fluctuation, the storage battery is temporarily moved from the sub storage battery toward the main storage battery. Large flowing currents must also be prevented. For this reason, at least when the voltage of the main storage battery drops to a voltage higher than the voltage of the sub storage battery by the first set voltage or more, the switch is opened to provide protection. Further, when the switch means shifts from the closed state to the open state, the OFF resistance rapidly increases when the state changes from the open state to the closed state.

With such an operation, a protection function against an excessive current is provided while using both the main and sub storage batteries in the best condition while using both.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram for explaining the principle,
FIG. 2 is an explanatory diagram of an example of an embodiment circuit, in which some components are omitted. The illustrated example is a storage battery charging control device 7 that controls charging of a main storage battery 3 connected to a power generation unit 1 (alternator) and a sub storage battery 5 connected to the main storage battery 3. Main voltage detecting means 9 for detecting the terminal voltage; auxiliary voltage detecting means 11 for detecting the voltage of the secondary storage battery 5; current detecting means 13 for detecting a current flowing from the main storage battery 3 toward the secondary storage battery 5; In addition to opening and closing between the storage batteries 3 and 5, the ON resistance is gradually reduced when the battery changes from the open state to the closed state, and is rapidly opened when the state changes from the closed state to the open state. When it is detected that the terminal voltage of the storage battery 5 has become higher than the terminal voltage of the storage battery 5 by the first set voltage and the terminal voltage of the main storage battery 3 has become higher than the second set voltage, the connection between the main and sub storage batteries 3 and 5 is made. Closed and at least the main The terminal voltage of the battery 3, or decreases to the first set voltage of more high voltage to the terminal voltage of 従蓄 battery 5, the current detecting means 13
Battery charging control device 7 comprising: switch means 15 for controlling to open between main and sub-storage batteries 3 and 5 when it is detected that the current value detected by the control device becomes higher than a predetermined set value. It is.

The embodiment shown in FIG. 1 includes a resistor 17 and resistor-end voltage detecting means 19 for detecting the voltage of the resistor 17 on the main and sub storage batteries 3 and 5 side. The magnitude of the current flowing from the main storage battery 3 toward the sub storage battery 5 is detected by comparing the resistance end voltage difference between the storage batteries 3 and 5 with the third set voltage.

The details will be described below. The main storage battery 3 for general traveling is connected to the power generating means 1 (alternator) on the vehicle side, and a standard load of the vehicle (not shown) is connected thereto. Further, a sub storage battery 5 is connected to the main storage battery 3 via a storage battery charging control device 7 of the present invention. The storage battery charging control device 7 basically includes a switch means 15 for opening and closing the main and sub storage batteries 3 and 5, and a control circuit unit 21 thereof. The control circuit unit 21 includes a voltage detection unit 23 including the main voltage detection unit 9, the sub-voltage detection unit 11, and the current detection unit 13, a switching control unit 25 that controls opening and closing of the switch unit 15, and supply to the circuit unit. The power supply unit 27 includes a power supply unit 27 that generates power, an overdischarge protection circuit unit 29 that prevents overdischarge of the storage battery 5, and an overcharge prevention circuit unit 31 that prevents overcharge of the storage battery 5. Further, a remaining capacity detection display section 33 of the secondary storage battery 5 is additionally provided.

Hereinafter, the circuit of this embodiment will be described in detail, together with the operation of each unit. On the main storage battery 3 side, first, second, and third three voltage dividing resistors 35, 37, and 39 are provided.
Further, on the side of the secondary storage battery 5, the fourth and fifth two voltage dividing resistors 4 are provided.
1 and 43 are configured and extracted as voltages for each operation determination. The voltage from the first voltage dividing resistor 35 is supplied to the non-inverting input of the comparator 45, and the voltage from the second voltage dividing resistor 37 is supplied to the inverting input of the comparator 47, and are compared with the reference voltage V _REF. . Of these two comparators 45 and 47, the comparator 47
It is determined whether the voltage of the main storage battery 3 is equal to or higher than the second set voltage. For example, when a 12 V storage battery is used as in this example, the output of the comparator 47 may be switched at 13.0 V. The comparator 45
In order to prevent overdischarge of the main storage battery 3, it is safer to set the switch means to open at 12.5 V or less, for example. The voltage from the third voltage-dividing resistor 39 is guided to the inverting input of the comparator 49 as the current detecting means 13 and the non-inverting input of the comparator 51, respectively. Here, the divided voltage of the terminal voltage of the storage battery side of the current detecting resistor 17 is led to the non-inverting input of the comparator 49. This voltage division can be set to an arbitrary predetermined voltage by the variable resistor 53, and is defined as a third set voltage serving as a reference value for overcurrent protection. on the other hand,
The voltage from the fourth voltage-dividing resistor 41 on the side of the secondary battery 5 is guided to the inverting input of the comparator 51. The value of the two voltage-dividing resistors 39 and 41 and the operation of the comparator 51 cause the main battery to operate. The voltage difference between the battery 3 and the secondary battery 5 is determined. This voltage difference is defined as a first set voltage. Here, when the switch means 15 is closed, it depends on the operation of the comparators 47 and 51, and when it is open, it depends on the operation of the comparator 45. However, the voltage becomes lower than the second set voltage. The switch means is maintained in a closed state until this time. The voltage from the fourth voltage dividing resistor 41 is supplied to the comparator 55
The non-inverting input of the comparator 55 is compared with the reference voltage V _REF which is the inverting input of the comparator 55 to determine the voltage of the secondary battery 5. This is defined as, for example, a fourth set voltage. In this example, for example, when this voltage is 10 V or less, control is performed so as not to close the switch means. This means that if the voltage of the secondary battery 5 is abnormally low, there is a possibility that an accident such as a short circuit has occurred in the load system of the secondary battery 5, and the application of the charging voltage leads to a serious accident. It is. Then, these five comparators 45, 47, 49, 51, 55
Is output to the flip-flop circuit 57 of the switching control unit 25 as shown in the figure, and the opening and closing of the switch means 15 (here, an N-channel type power MOS FET) is controlled.

The switching control unit 25 mainly comprises the flip-flop circuit 57, the inverter unit 59, and the charge pump (boost) circuit 61.
The opening / closing control of the switch means 15 is performed by the output from the switch. The voltage difference between the main storage battery 3 and the secondary storage battery 5 is compared by the comparator 51, and it is determined that the voltage of the main storage battery 3 is higher than the voltage of the storage battery 5 than the first set voltage. When it is determined that the voltage of the main storage battery 3 is higher than the second set voltage, the transistor 63 is turned on via the flip-flop circuit 57.
It becomes FF. Then, the charge of the capacitor 65 is held, and the operation of the inverter unit 59 causes the transistor 71 to be turned off when the transistors 67 and 69 are OFF.
N, conversely, an oscillating operation in which the transistor 71 is turned off when the transistors 67 and 69 are turned on is performed. At this time, due to the operation of the charge pump circuit 61, _VBB of 2
The doubled voltage is stored in the capacitor 73, the switch means 15 is closed, and remains closed as long as the oscillation of the inverter unit 59 continues. The transition time when the switch means 15 is closed is set to about 1 millisecond by the gate delay resistor 75 to prevent an inrush current at the time of switching to the secondary battery 5. This gate delay resistor 75
Is set to about 50 kOhm in the circuit of this embodiment. This is an extremely high value as the gate resistance of the FET as compared with a resistance value used in common sense. Next, the operation of the charge pump circuit 61 in this embodiment will be described with reference to FIG. Transistor 71 is O
When the transistor 69 is OFF at N (a), V
The bias from _BB causes the resistance 77 to the diode 7
9, and the charging current flows into the capacitor 81,
The capacitor 81 is charged. Next, the transistor 71 is turned off and the transistor 69
Is turned on (b), _VBB and the capacitor 8
1 are connected in series, and the capacitor 73 is approximately 2 × V
It will be charged with the voltage of _BB . At this time, since the directions of the diodes 79 and 83 are reversed,
3,81 charges do not disappear. Due to the charge accumulated in the capacitor 73, the voltage of 2 × V _BB is continuously applied to the gate of the switch means 15, and the switch means is maintained in the closed state while the inverter section 59 continues the oscillating operation. Therefore, the power storage means 5 is charged from the power generation means 1 (alternator).

When the voltage of the secondary storage battery 5 rises due to charging, if the voltage of the primary storage battery 3 is temporarily reduced by, for example, turning a cell motor while the switch means 15 is closed, the secondary storage battery 5 side Therefore, in the present invention, the voltage of the main storage battery 3 is reduced to a voltage higher than the voltage of the sub storage battery 5 by a first set voltage or more. At this point, control is performed to open the switch means 15. Also, when it is determined that the current value to the secondary battery 5 is higher than the third set voltage determined by the variable resistance by the operation of the comparator 49,
The switch means is opened for overcurrent protection, and when the voltage of the main storage battery 3 becomes a predetermined set voltage lower than the second set voltage, the switch means 15 is opened by the operation of the comparator 45. , Of course. When the voltage of the secondary battery 5 increases, the operation of the comparator 51 is received, and the transistor 63 is turned on by the output of the flip-flop circuit 57. When the transistor 63 is turned on, the charge of the capacitor 65 is discharged, and as a result, the charge pump circuit 61 stops. At the same time, the transistor 85 is also turned on, and the gate of the switch 15 is set to the ground potential. As a result, the switch 15 is opened. The transition of the switch means from the closed state to the open state at this time is substantially governed by the rise time of the transistor 85 and has a steep fall characteristic. In the case of protection against overcurrent, the switch means 15 is opened by the operation of the comparator 49 in the same manner as described above.

In this way, the terminal voltage of the main storage battery 3 becomes higher than the terminal voltage of the sub storage battery 5 by the first set voltage and the terminal voltage of the main storage battery 3 becomes higher than the second set voltage. The main battery 3 and the sub-battery 3 are closed when it is detected that the terminal voltage of the main storage battery 3 has dropped to a voltage higher than the terminal voltage of the sub-battery 5 by a first set voltage or more. Alternatively, when it is detected that the current value detected by the current detecting means 13 has become higher than a predetermined set value, control is performed so as to open the main and sub storage batteries 3 and 5. Further, the operation of the gate delay resistor 75 and the transistor 85 having a large value allows
The switch means 15 operates such that the ON resistance gradually decreases when the state shifts from open to closed, and opens sharply when the state shifts from close to open.

Next, the overdischarge protection circuit 29 of the secondary battery 5
The overcharge prevention circuit 31 will be described. The voltage from the fifth voltage-dividing resistor 43 is led to the inverting input of the comparator 87 of the over-discharge protection circuit 29, and the reference voltage V _REF is led to the non-inverting input. The voltage from the fourth voltage-dividing resistor 41 is guided to the non-inverting input of the comparator 89, and the reference voltage V _REF is guided to the inverting input. These two comparators 87, 8
9, the comparator 87 determines whether the secondary battery 5 is at or above the fifth set voltage (for example, 12.3 V in this example), and the comparator 89 determines whether the storage battery 5 is at the sixth set voltage (for example, this example). Is determined to be 10.0 V) or less. When the voltage of the secondary battery 5 drops below the sixth set voltage, the output of the flip-flop circuit 91 turns off the transistor 93. As a result, the switch to the load 97 is opened by the relay (coil) 95, and the power supply from the secondary battery 5 to the load 97 is stopped. This is because a lead storage battery is usually used for the secondary storage battery 5 of the camper, but when the lead storage battery is completely discharged,
This is because the life is significantly shortened. When the voltage becomes equal to or higher than the fifth set voltage (generally, a value equal to or higher than the sixth set voltage as in this example), the power supply to the load 97 is restored by the reverse operation. On the other hand, overcharge protection is prevented by the operation of the switch means 15 described above.
If the voltage of the secondary battery 5 rises abnormally for some reason, it is necessary to forcibly discharge the secondary battery 5 to protect it. When the voltage of the secondary storage battery 5 becomes abnormally high, the transistors 99 and 10 of the overcharge prevention circuit 31
The operation 1 causes the secondary battery 5 to be discharged to a predetermined voltage level.

The remaining capacity of the secondary battery 5 is monitored by a voltmeter 103.
3 and the voltmeter control circuit 105 to display the remaining capacity
3 are configured. Next, the remaining capacity detection display section 33 will be described. The basic function is to guide the voltage of the storage battery 5 to generate a constant voltage (10 V in this embodiment) by the three-terminal regulator 109, and to calculate the difference between the terminal voltage of the storage battery 5 and this constant voltage by a large capacity. Condenser 111
Is displayed on the voltmeter 103 as a buffer.
When the storage battery 5 which is in a fully charged state is first connected, the transistor 113 is turned on by a sufficient terminal voltage, and the capacitor 111 is rapidly charged by a current path passing through the resistor 115 and the transistor 113. It occurs on the plus side of the total 103. On the other hand, on the minus side of the voltmeter 103, a resistor 117 is provided.
And a voltage determined by the diode 119 is generated. The voltage difference between the plus side and the minus side is displayed on the voltmeter 103. Although the terminal voltage of the capacitor 111 increases as the voltage of the storage battery 5 increases, the voltmeter 103 takes time to respond to the time required for charging the capacitor 111. On the other hand, when the voltage of the storage battery 5 decreases due to the power supply to the load 97, the charge of the capacitor 111 is reduced to the diode 121 and the resistor 1
Since the electric current is discharged through 23, the display of the voltmeter 103 changes as the terminal voltage of the capacitor 111 decreases. Also at this time, the resistor 123 acts as a time constant of the discharge, so that the voltmeter 103 reacts for a time determined by the time constant. On the other hand, it is necessary to keep the voltmeter 103 from swinging even if the voltage in the fully charged state varies. Therefore, in this embodiment, four series diode units 125 are used. For example, storage battery 5
Is 12 V, which is the full voltage of a general automobile battery, the voltage at point A is
Due to the action of 09, the voltage becomes 2V. On the other hand, the voltage at the point B is about 0.7 V due to the effect of the diode 119. Therefore, the voltage difference between the two points AB, 1.3 V, is measured by the voltmeter 1.
03 is displayed. Here, considering the case where the secondary battery 5 whose full voltage is higher than 12 V is connected, it is desirable to display the full state without turning off the voltmeter 103. Assuming that the voltage is 16 V, the voltage at point B is 0.7 V, but the voltage at point A is 6 V if the diode unit 125 is not provided. Do you miss 103?
Or if you set it so that you can not swing it, 12V in full state
When the secondary battery 5 is connected, the remaining capacity is displayed to be extremely small. However, when the diode unit 125 is provided, the rising voltage of each diode is about 0.7 V, so that it becomes 2.8 V at the point A, and 2.1 V which is the difference between 2.8 V and 0.7 V is measured by the voltmeter 103. Will be displayed. That is, even if there is a difference of 4 V (16 V-12 V) in the voltage of the storage battery 5 in the full state, the voltmeter 10
3 is only an increase of 0.8 V (2.1 V-1.3 V). Thus, the voltage of the storage battery 5 minus -10
When V exceeds the rising voltage (here, for example, 2.8 V) of four diodes in series, the diode unit 1
Since the reference numeral 25 functions as a bypass path, when the high-voltage storage battery 5 is connected, the terminal voltage difference between the diode 119 and the diode unit 125 is reflected on the indicated value of the voltmeter 103. Moreover, by using the normal diode forward direction, the change in the indicated value of the voltmeter 103 can be made broad. Therefore, even if the full voltage of the connected storage battery 5 varies, the voltmeter 103 can always be displayed as the remaining capacity near full without the swing of the voltmeter 103.

At the time of overdischarge, the power supply to the load 97 is stopped by the relay 95 as described above.
Immediately before the power supply to the power supply is cut, the voltmeter 103 indicates a value near zero (not the voltage of 0 V but the storage battery capacity of zero). Here, when the power supply to the load 97 is cut, the terminal voltage of the storage battery 5 naturally rises. At this time, if the indication of the voltmeter 103 rises, an illusion that the capacity of the secondary battery 5 has recovered may be caused. Therefore, even when the power supply to the load 97 is stopped, the remaining capacity is not changed. It is desirable to keep it at zero. In the present embodiment, when the voltage of the secondary battery 5 drops below the sixth set voltage, the transistor 127 is turned on to discharge the charge of the capacitor 111 and clamp the indication of the voltmeter 103 near zero. Has become. And load 9
Voltmeter 1 with voltage rise when power supply to 7 is cut
In order to prevent the reaction of the battery 03, the voltage obtained from the fourth and fifth voltage-dividing resistors 41 and 43 is given a difference so that the storage battery 5 at that time differs from the load cut voltage (sixth set voltage).
Is set as a voltage (fifth set voltage) at which the load is restored, that is, the transistor 127 is turned on.

The above-described mechanism for detecting the remaining capacity based on the voltage does not respond to the gradual change in the voltage, and the accuracy of the indication is reduced by the action of the diode 119 and the diode unit 125 near the upper limit of the voltage. Therefore, it is also excellent as a control device for the voltmeter. For example, besides the remaining capacity of the storage battery as in this example, it is possible to cut off instantaneous high abnormal values such as tide level, water current, wind speed, etc. It can be said that it is suitable for applications such as monitoring the fluctuation range.

[0020]

As described above, according to the present invention, the on-resistance of the switch means for opening and closing the main and sub storage batteries gradually decreases when the switch means changes from open to closed, and the switch means sharply changes when the switch means changes from close to open. The terminal voltage of the main storage battery is higher than the terminal voltage of the sub storage battery by the first set voltage or more, and the terminal voltage of the main storage battery is higher than the second set voltage. When it is detected that the main battery and the auxiliary battery are closed, at least the terminal voltage of the main battery decreases to a voltage higher than the terminal voltage of the auxiliary battery by a first set voltage or more, or is detected by the current detecting means. When it is detected that the current value to be supplied becomes higher than a predetermined set value, the main and sub-storage batteries are controlled so as to be opened, so that both the main and sub-storage batteries supplying power to the individual loads are connected. , One from the power generation means and power supply means, at a sufficiently made the state also protection of the battery without fear of inrush current,
It is possible to charge in a safe and efficient manner. In particular, the switch means for opening and closing between the main battery and the secondary battery is FE.
By using T and setting the gate resistance to a resistance value of several tens of kilohm class, which is not commonly set in a normal electronic circuit, the above-described excellent circuit configuration can be achieved without using a complicated protection circuit. The effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of a storage battery charging control device according to the present invention.

FIG. 2 is a diagram for explaining an example of an implementation circuit of the storage battery charge control device of the present invention.

FIG. 3 is a diagram illustrating the principle of a charge pump circuit according to an embodiment of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 power generation means 3 main storage battery 5 sub storage battery 7 storage battery charging control device 9 main voltage detection means 11 sub voltage detection means 13 current detection means 15 switch means 17 resistor 19 resistance end voltage detection means 21 control circuit section 23 voltage detection section 25 switching control Unit 27 Power supply unit 29 Overdischarge protection circuit unit 31 Overcharge prevention circuit unit 33 Remaining capacity detection display unit 35, 37, 39 Dividing resistor 41, 43 Dividing resistor 45, 47, 49, 51, 55, 87, 89 Comparator 53 Variable resistor 57, 91 Flip-flop circuit 59 Inverter section 61 Charge pump circuit 63, 67, 69, 71, 85, 93, 99 Transistor 65, 73, 81, 111 Capacitor 75 Gate delay resistor 77, 115, 117 , 121, 123 Resistance 79, 83, 119, 121 De 95 Relay 97 load 101,113,127 transistor 103 voltmeter 105 voltmeter control circuit 107 remaining capacity detection display unit 109 three-terminal regulator 125 diode unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01R 31/36 G01R 31/36 A H02J 7/14 H02J 7/14 HF term (Reference) 2G016 CA03 CB11 CB12 CB31 CC01 CC04 CC06 CC08 CC12 CC15 CC23 CD04 CD06 CD07 CD09 CD10 CD14 CE00 2G035 AA16 AA21 AB03 AC01 AC02 AC16 AC19 AD02 AD03 AD04 AD05 AD08 AD10 AD11 AD16 AD17 AD20 AD23 AD50 AD54 5G003 AA07 BA02 CA01 CA11 CC02 DA07 DA11 FA04 GA04 DA01 DB01 DB03 DB05

Claims (2)

[Claims] 1. A storage battery charge control device for controlling charging of a main storage battery connected to a power generation means and a sub storage battery connected to the main storage battery, the main voltage detection means detecting a terminal voltage of the main storage battery. A secondary voltage detecting means for detecting a voltage of the secondary battery, a current detecting means for detecting a current flowing from the main storage battery toward the secondary storage battery, and opening and closing between the primary and secondary storage batteries. The ON resistance is gradually reduced, and is configured to open sharply at the time of transition from the closed state to the open state. The terminal voltage of the main storage battery becomes higher than the terminal voltage of the auxiliary storage battery by the first set voltage or more, and When detecting that the terminal voltage of the storage battery has become higher than the second set voltage, the main and sub storage batteries are closed, and at least the terminal voltage of the main storage battery is the first set voltage with respect to the terminal voltage of the storage battery. Minute Or lowered to the upper high voltage,
A storage battery charging control device, comprising: a switch device that is controlled to open the main and sub storage batteries when it detects that the current value detected by the current detection device has become higher than a predetermined set value. 2. The current detecting means comprises a resistor interposed between the main battery and the secondary battery, and a resistor end voltage detecting means for detecting a voltage of the resistor on the main battery and the secondary battery.
The magnitude of a current flowing from the main storage battery side to the sub storage battery side is detected by comparing a resistance end voltage difference between the main storage battery side and the secondary storage battery side with the third set voltage. The storage battery charge control device according to any one of the preceding claims.