JP2003304649A - Charging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charging device, capable of recovering the capacity of a secondary battery to such a degree that the battery can be backed up early as necessary, without decreasing the reliability of the battery. <P>SOLUTION: This charging device, having a charging control circuit 2, which charges the secondary battery BT with prescribed charging current at the initial charging by the output of an AC/DC conversion circuit 1 for converting a stepped-down commercial power source into a DC power supply and then switches it to charging of a level for compensating the self-discharge, includes a human feel sensor 3. Upon detecting a person, the human feel sensor 3 switches the initial charging current to a current higher than a prescribed preset current for charging. In place of the feel sensor, an illumination sensor or a temperature sensor may also be used. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to charge control of a secondary battery such as a nickel-cadmium battery or a nickel-hydrogen battery used in a charging device or an emergency lighting device.

[0002]

2. Description of the Related Art Conventionally, as a method of charging a device such as an emergency light or an induction light which uses a secondary battery as a backup power supply source when a commercial power source fails, as shown in FIG. / 20 CmA to ⅕ CmA charging current and then reducing to 1/50 CmA charging current to perform supplementary charging, or as shown in FIG.
There is a method of charging with a charging current of about CmA to 1/5 CmA, and then intermittently charging. (Here, "Cm
"A" means a value (current value) obtained by dividing the nominal capacity of the battery by 1 hour. )

Since these charging methods are initially charged with a relatively large current, compared to the charging method of charging with a constant current (so-called trickle charging), the capacity recovery after discharging due to a power failure or the like is performed. This is a quick charging method.

[0004]

Generally, in a backup device such as an emergency light or an induction light, it is safer for the device to have a shorter time until the capacity after discharge is restored to a backupable state. Needless to say, it has a high quality. However, if the charging current is increased to shorten the time until the capacity is restored, the temperature of the battery in the vicinity of full charge rises extremely, which causes a problem that the deterioration of the secondary battery is accelerated.

Therefore, it is necessary to charge the secondary battery with a current such that the temperature does not rise to a high temperature even during initial charging. For example, with a charging current of 1/5 CmA, it takes about 7.5 hours to reach a fully charged state. Time is required and this 7.5
If a power failure occurs again during the time, there is a problem that the lighting time required by law as an emergency light or a guide light cannot be secured.

From the above, it is needless to say that in a backup device, it is safer for the device to have a shorter time until the capacity after discharge is restored to a backupable state.

The present invention provides a charging device capable of restoring the capacity of a secondary battery to a state in which it can be backed up promptly when necessary while minimizing the influence on the reliability of the battery as much as possible. It is an issue.

[0008]

In order to solve the above-mentioned problems, according to the present invention, as shown in FIG. 1, an AC-DC conversion circuit 1 for stepping down a commercial power supply AC and converting it into a DC power supply.
And means for supplying a charging current to the secondary battery BT by the output of the AC-DC conversion circuit 1 (current limiting resistor R), and charging at a predetermined charging current at the initial stage of charging and thereafter at a level of supplementing self-discharge In a charging device having a charge control circuit 2 for switching to and a motion sensor 3, when the motion sensor 3 detects a person, charging is performed by switching an initial charging current to a current higher than a predetermined set current. It is what Instead of the human sensor 3, an illuminance sensor (FIG. 5) or a temperature sensor (FIG. 7) may be used. A nickel hydrogen battery may be used as the secondary battery BT.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a first embodiment of the present invention. Explaining the circuit configuration of FIG. 1,
A that converts the AC voltage of the commercial power supply AC into a predetermined DC voltage
A C / DC conversion circuit 1, a power failure detection circuit 4 for detecting a power failure of the commercial power supply AC, and a secondary battery B connected to the output of the AC / DC conversion circuit 1 via a resistor R and a transistor Q1.
T, a charge control circuit 2 for controlling ON / OFF of the transistor Q1, a load 6 (lamp) connected to the secondary battery BT via the transistor Q2, and an output of the power failure detection circuit 4 to turn on the transistor Q2. It is composed of a discharge control circuit 5 which is turned on to perform discharge. SW is a switch for inspection and 3 is a human sensor.

When the commercial power supply AC is energized, the commercial power supply AC is stepped down and rectified by the AC / DC conversion circuit 1 to be converted into a low DC voltage to charge the secondary battery BT. A
The C / DC conversion circuit 1 is controlled by the charging control circuit 2, and the control signal S4 of the charging control circuit 2 switches the output between a high level V2 and a low level V1 (<V2).
The charging control circuit 2 has a time measuring means (timer) for measuring the charging time inside. When a power failure occurs, the power failure detection circuit 4 detects the power failure, the charge control circuit 3 stops charging, and at the same time, the discharge control circuit 5 turns on the transistor Q2 so that the battery BT serves as a power source and supplies power to the load 6. . In this embodiment, a human sensor 3 is provided in the charging device, and the charging control circuit 2 switches the charging operation according to the output of the human sensor 3. 2 and 3 show time charts. A flowchart is shown in FIG.

First, the case where the motion sensor 3 senses a person (FIG. 2) will be described. When a person is detected by the human sensor 3 when the power is turned on, such as when power is restored after a power failure, the output S5 of the human sensor 3 outputs a high level. In the charge control circuit 2, the output S5 of the motion sensor 3 is Hi.
If it is the gh level, a high level signal is output as the control signal S4, and the output voltage of the AC / DC conversion circuit 1 is controlled to the high level V2. At the same time, the control signal S1 becomes Low level, and the output transistor Q1 becomes O.
Then, the timer provided in the charge control circuit 2 starts counting. A charging current Ic2 determined by the output V2 of the AC / DC conversion circuit 1 and the current limiting resistance R flows in the secondary battery BT to be charged.

When the timer count value becomes t = T1, the timer count is reset, and at the same time, the charge control circuit 2 sets the control signal S1 to the high level and the control signal S4 to the low level to turn off the transistor Q1 to stop the charging. Becomes Then, the timer starts counting again.

When the timer count value becomes t = T2, the timer count is reset, and at the same time, the charging control circuit 2 sets the control signal S4 to Low level and the control signal S1 to L level.
At the ow level, the transistor Q1 is turned on to start the charging operation, and the charging current Ic1 flows. Then, the timer starts counting again.

When the timer is again charged and the timer count value becomes t = T3, the charge control circuit 2 sets the control signal S1 to the high level to turn off the transistor Q1 to stop the charging operation and at the same time reset the timer count. To do.

In the subsequent operation, the charging is intermittently performed by repeating the charging suspension period T2 and the charging period T3 by the timer. The charging operation after the power is turned on is called initial charging, and the charging operation after the charging suspension operation is called auxiliary charging. The initial charging time T1 is set so that an empty battery can be fully charged, and the charging time T3 is set.
Is set to a time shorter than the charging pause time T2.

Specific setting values are shown below. The initial charge is set so that the battery will be fully charged from an empty state.
Generally, the maximum charging current of the battery is within 2C, so if the initial charging current is 2CmA, the initial charging time T
If 1 is set to about 0.75 hours, the battery can be fully charged. The charging suspension time T2 is set so as to compensate for the decrease in the capacity of the battery due to the amount of self-discharge of the battery. The self-discharge current varies depending on the battery temperature and is generally 1/500 CmA to 1
It is about / 2500 CmA. If the self-discharge amount is reduced by about 20% of the rated capacity, the down time T2 is 100
The time may be set to about 500 hours. The supplementary charging time T3 is set to a level lower than that of the initial charging with the charging current set to 0.1 CmA. Since the amount of decrease in capacity is 0.2 CmAh, the amount of supplementary charge is required to be about 1.2 to 2 times that amount, and since it is charged from about 0.24 CmA to about 0.4 CmA, the supplementary charging time T3 is about 2.4 to 4 hours. Set to.

Next, the case where the human sensor 3 does not detect a person (FIG. 3) will be described. If the human sensor 3 does not detect a person when the power is turned on, such as when power is restored after a power failure, a low-level signal is output from the output S5 of the human sensor 3. If the output S5 of the motion sensor 3 is at the low level, the charging control circuit 2 outputs Lo from the control signal S4.
A w-level signal is output, and the output voltage of the AC / DC conversion circuit 1 is controlled to a low level V1. At the same time, the control signal S1 goes low and the output transistor Q
When 1 is turned on to start charging, the timer provided in the charging control circuit 2 starts counting. Secondary battery B
The charging current Ic1 determined by the output V1 of the AC / DC conversion circuit 1 and the current limiting resistance R flows through T and is charged. Here, the level V1 of the output voltage of the AC / DC conversion circuit 1 when the person is not sensed is the level V1 when the person is not sensed.
The voltage is set to be lower than 2.

When the timer count value becomes t = T4, the charge control circuit 2 sets the control signal S1 to High level to turn off the transistor Q1 to stop the charging operation and at the same time reset the timer count. The initial charging time T4 is set to a time in which the battery BT is in a fully charged state when the charging current is Ic1. Subsequent operations are the same as when the human sensor 3 detects a person.

(Second Embodiment) FIG. 5 shows a second embodiment of the present invention.
It is a circuit diagram of. The difference from the first embodiment is that the illuminance sensor 7 is used instead of the human sensor 3 of FIG. 9, and it is presumed that a person is present when the surroundings are bright. Therefore, the charging current is increased to speed up capacity recovery. , It is presumed that there are no people when the surroundings are dark, so the operation is performed to lower the charging current. The operation of this embodiment is shown in the flowchart of FIG. In an environment where people are always present, conversely to the above, it can be said that the urgency is higher when the surroundings are dark, so even if it is operated to increase the charging current when the surroundings are dark. good.

(Third Embodiment) FIG. 7 shows a third embodiment of the present invention.
It is a circuit diagram of. The difference from the first embodiment is that the temperature sensor 8 is used in place of the human sensor 3 of FIG. 9, and the battery temperature does not increase when the ambient temperature is low, so the charging current is increased and the capacity recovery is accelerated. When the temperature is high, the battery temperature tends to be high, and therefore the charging current is reduced. The operation of this embodiment is shown in the flowchart of FIG.

As another example, there is a method of charging the auxiliary charge after the initial charge with a constant current of 1/50 CmA (called trickle charge). In short, it suffices to switch the current level of the initial charge according to the output of sensing means such as a human sensor, an illuminance sensor, and a temperature sensor.

[0022]

According to the present invention, the current level of the initial charge is switched according to the output of the sensing means such as the human sensor, the illuminance sensor, and the temperature sensor, so that the backup can be performed quickly when the urgency is high. It is possible to improve the safety by restoring the capacity of the secondary battery to the state, and to suppress the temperature rise of the secondary battery by reducing the charging current when the urgency is low in other cases. It has the effect of extending the service life.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a first embodiment of the present invention.

FIG. 2 is a time chart showing an operation at the time of detection according to the first embodiment of the present invention.

FIG. 3 is a time chart showing an operation during non-detection according to the first embodiment of the present invention.

FIG. 4 is a flowchart for explaining the operation of the first embodiment of the present invention.

FIG. 5 is a circuit diagram of a second embodiment of the present invention.

FIG. 6 is a flowchart for explaining the operation of the second embodiment of the present invention.

FIG. 7 is a circuit diagram of a third embodiment according to the present invention.

FIG. 8 is a flowchart for explaining the operation of the third embodiment of the present invention.

FIG. 9 is an operation explanatory diagram of Conventional Example 1.

FIG. 10 is an operation explanatory diagram of Conventional Example 2.

[Explanation of symbols]

1 AC / DC conversion circuit 2 Charge control circuit 3 sensor 4 Power failure detection circuit 5 Discharge control circuit 6 load 7 Illuminance sensor 8 temperature sensor BT secondary battery

Continued front page    (72) Inventor Hiroyuki Nishino             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works             Within the corporation F term (reference) 5G003 AA01 BA01 CA02 CB06 GC04                 5H030 AA00 BB03 FF00 FF21

Claims (4)

[Claims] 1. An AC-DC converting means for stepping down a commercial power source to convert it into a DC power source, a means for supplying a charging current to a secondary battery by the output of the AC-DC converting means, and a predetermined charging current at the initial stage of charging. In a charging device that has a human body sensor and a charging control means that switches to charging at a level that compensates for self-discharge after that, when the human body sensor detects a person, the initial charging current is higher than a predetermined set current. A charging device characterized by switching to and charging. 2. An AC-DC converting means for stepping down a commercial power source to convert it into a DC power source, a means for supplying a charging current to a secondary battery by the output of the AC-DC converting means, and a predetermined charging current at the initial stage of charging. In a charging device that has charging control means that switches to charging at a level that compensates for self-discharge after that, and a charging device that has an illuminance sensor, when the illuminance is high, the initial charging current is switched to a current higher than a predetermined set current for charging. Charging device characterized by performing. 3. An AC-DC converting means for stepping down a commercial power source to convert it into a DC power source, a means for supplying a charging current to a secondary battery by the output of the AC-DC converting means, and a predetermined charging current at the initial stage of charging. In a charging device that has a temperature sensor and a charging control unit that switches to charging at a level that compensates for self-discharge after that, when the temperature is low, the initial charging current is switched to a current higher than a predetermined set current for charging. Charging device characterized by performing. 4. The charging device according to claim 1, wherein a nickel-hydrogen battery is used as the secondary battery.