JPH0633649Y2 - Charger - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a charger that charges a storage battery such as a Ni-Cd battery in a short time.

[Conventional technology]

Ni-Cd battery is a camera-integrated type as a rechargeable secondary battery
The production volume is increasing year by year with the spread of portable equipment such as VTRs. Ni-Cd batteries have the drawback of low voltage, but they are suitable for driving motors, etc., because they can draw large currents. In addition, it has the advantages of being resistant to overcharging and overdischarging, and having a long service life, making it a highly usable power source.

Recently, there is an increasing demand for rapid charging in order to effectively use such Ni-Cd batteries. In the past, many devices required charging for a long time, but the number of devices capable of charging in an hour or even shorter due to rapid charging is increasing. Therefore, a rechargeable secondary battery having a large capacity such as a Ni-Cd battery has come to be used as a driving power source.

A charger that performs such rapid charging is, for example, a commercial 100V
It is equipped with a rectification / stabilization circuit that rectifies and stabilizes the AC voltage of the rechargeable battery. The DC voltage stabilized by this rectification / stabilization circuit is used to charge secondary batteries (hereinafter referred to as storage batteries). There is.

When charging for 1 hour with such a charger, when the terminal voltage of the storage battery reaches the full charge voltage, rectification
The stabilizing circuit is controlled to flow about 1/3 of the charging current.

[Problems to be solved by the device]

However, in the above-mentioned conventional charger, for example, when charging is performed by further shortening the time to about 30 minutes, the charging current becomes large, and at the positive and negative charging terminals that supply the charging current to the storage battery, contact is made. Since a voltage is generated by the resistance and this voltage is added to the charging voltage, the terminal voltage of the storage battery cannot be accurately determined. For this reason, there is a problem in that the stabilization circuit is not accurately controlled and an excess or deficiency of charging occurs.

[Means for Solving the Problems]

The charger according to the present invention is made in order to solve the above-mentioned problems, and by determining the charging state of the storage battery during the charging suspension, the contact resistance between the storage battery and the charging terminal of the charger is determined. It is intended to be charged accurately without being affected.

That is, the charger according to claim 1 includes a charging current generation unit that generates a charging current to be supplied to the storage battery, a charging current supply unit that supplies the charging current generated by the charging current generation unit to the storage battery, and a charging circuit. Rapid charging means for performing rapid charging for a predetermined time on a storage battery for operating the current supply means,
A charge suspension means for stopping the operation of the charging current supply means and suspending the charging of the storage battery for a predetermined time with the end of the quick charging by the quick charging means, and a supplementary charge for operating the charging current supply means and performing the supplementary charge for the storage battery for the predetermined time. Means for determining whether the terminal voltage of the storage battery is higher than a predetermined level or lower than the predetermined level immediately before the termination of the charging suspension by the charging suspension means, and the terminal voltage determination means determines the terminal voltage of the storage battery at a predetermined level. When it is determined to be lower, the quick charging means is selected, while when it is determined to be higher than a predetermined level, the auxiliary charging means is selected to charge the storage battery.

Further, the charger according to claim 2 includes auxiliary charging control means for performing auxiliary charging by the auxiliary charging means when rapid charging by the rapid charging means and charging suspension by the charging suspension means are repeated a predetermined number of times. It is characterized by having.

[Action]

In the structure of claim 1, the rapid charging means operates the charging current supply means to supply the charging current generated by the charging current generating means to the storage battery to perform rapid charging for a predetermined time. When the rapid charging is completed, the charging suspension means stops the charging current supply to the storage battery and suspends the charging for a predetermined time. The charging suspension is set to be performed for a very short time with respect to rapid charging.

Immediately before the end of the charging suspension time, the terminal voltage determination means determines whether the terminal voltage of the storage battery is higher than or lower than a predetermined level. This predetermined level is set to the full charge voltage, for example. When the terminal voltage of the storage battery is higher than a predetermined level, the charging is completed by operating the auxiliary charging means by the charging selection means and performing auxiliary charging for a predetermined time. Supplementary charging is performed to the extent that the storage battery supplements the power lost due to self-discharge. On the other hand, when the terminal voltage is lower than the predetermined level, the charge selecting means operates the quick charging means to perform the quick charging for a predetermined time. After the rapid charging, the charging suspending means suspends the charging, and immediately before the end of the charging suspending period again, the terminal voltage determining means determines the terminal voltage, and the charging selecting means selects the rapid charging or the supplementary charging.

In this way, during charging pause, the charging current is not supplied to the storage battery, and conversely only a small amount of self-discharge current flows from the storage battery, so contact resistance between the storage battery terminal and the charging terminal of the charger The voltage drop that occurs is negligible. Therefore, by determining the level of the terminal voltage of the storage battery by the terminal voltage determination means during the charging suspension, accurate voltage determination can be performed with almost no influence of the above voltage drop.

Further, according to the structure of claim 2, during the charging suspension, the terminal voltage determining means determines the level of the terminal voltage of the storage battery, and after the termination of the charging suspension, the charging selecting means performs quick charging or supplementary charging. However, since the auxiliary charging control means is provided, when the rapid charging and the charging suspension are repeated a predetermined number of times by the auxiliary charging control means, the auxiliary charging is performed. Is performed for a predetermined time. Therefore, if the number of repetitions is set so that the storage battery will be in a nearly fully charged state when the repetition of the rapid charging and the charging suspension is completed, the battery is continuously charged even though it is in the fully charged state during the rapid charging. It is possible to prevent the overcharge state from being caused.

[Embodiment according to Claim 1] The following will describe one embodiment according to Claim 1 of the present invention with reference to FIG.

As shown in FIG. 1, the rectification / stabilization circuit 2 is connected to the outlet 1, and the rectification / stabilization circuit 2 is connected to the emitter of the transistor Tr ₂ and via the resistor R ₁ . Connected to the emitter of the transistor Tr ₁ . The collectors of the transistors Tr ₁ and Tr ₂ are both connected to the charging terminal 3 and also to the input terminals of the comparators 4 and 5. A charging terminal 6 is provided so as to face the charging terminal 3 and is grounded. The output terminal of the comparator 4 is connected to the input terminal A of the microcomputer 7, while the output terminal of the comparator 5 is connected to the input terminal B of the microcomputer 7. The output terminals C and D of the microcomputer 7 are connected to the bases of the transistors Tr ₁ and Tr ₂ via resistors R ₂ and R ₃ , respectively.

The rectification / stabilization circuit 2 serves as a charging current generation unit that rectifies a commercial 100V AC voltage input from the outlet 1 and generates a DC voltage to be supplied to the storage battery 11. On the other hand, the transistors Tr ₁ and Tr ₂ are controlled to be turned on and off by the microcomputer 7 so as to supply the direct current output from the rectification / stabilization circuit 2 to the storage battery 11. Is working as. The charging terminals 3 and 6 respectively correspond to the positive electrode and the negative electrode of the storage battery 11, and the storage battery 11 is charged through the charging terminals 3 and 6.

When the storage battery 11 is inserted between the charging terminals 3 and 6, and the voltage of the charging terminals 3 and 6 decreases and becomes equal to or lower than a preset reference voltage, the comparator 4 outputs a high level signal to the microcomputer 7. It sends a signal to start charging.

On the other hand, the comparator 5 sends a high level signal to the microcomputer 7 when the terminal voltage of the storage battery 11 becomes equal to or higher than the preset comparison voltage (predetermined level), that is, the full charge voltage. It operates as voltage determination means and charge selection means.

The microcomputer 7 turns on the transistors Tr ₁ and Tr ₂ for a predetermined time depending on whether the high level signal from the comparator 4 or the low level signal from the comparator 5 is input. Then, a charging current is supplied to the storage battery 11, and it operates as a quick charging means. Further, when the rapid charging is completed, the transistors Tr ₁ and Tr ₂ are turned off for a predetermined time to suspend the charging, and it operates as a charging suspending means. Further, the microcomputer 7 operates as an auxiliary charging means for performing auxiliary charging by turning on only the transistor Tr _{1 for} a predetermined time to supply the charging current to the storage battery 11, and the high level from the comparator 5 When the signal of is input, auxiliary charging is performed.

In the above configuration, the rectification / stabilization circuit 2 rectifies a commercial 100V AC voltage supplied through the outlet 1 to obtain a stabilized DC voltage, which is about 4 to 5V. It appears as an open circuit voltage at the charging terminal 3. At this time, the comparator 4 does not output a high level signal because a voltage equal to or higher than the reference voltage set to about 2V is input.

Here, when the storage battery 11 is inserted between the charging terminals 3 and 6, the voltage of the charging terminal 3 drops to about 1.5 V and the input voltage of the comparator 4 becomes equal to or lower than the reference voltage. Is output. The microcomputer 7 is a comparator 4
Upon receiving the high level signal from causes ON and bias Tr ₁ · Tr _2. When the transistors Tr ₁ and Tr ₂ are turned on, the storage battery 11 is supplied with a charging current via the transistors Tr ₁ and Tr ₂ to perform rapid charging. Then, when charging is performed for a predetermined time, the microcomputer 7 causes the transistor Tr
It is OFF the ₁ · Tr ₂ to terminate the rapid charge.

After the rapid charging is completed, the transistors Tr ₁ and Tr ₂ are kept in the OFF state for a predetermined time by the microcomputer 7, and the charging is in the resting state. Immediately before the end of the charging suspension state, the comparator 5 determines whether the terminal voltage of the charging terminal 3 is equal to or lower than the full charge voltage. If the voltage of the charging terminal 3 is equal to or lower than the full charge voltage, the microcomputer 7 turns on the transistors Tr ₁ and Tr ₂ to perform rapid charging again for a predetermined time. If the voltage of the charging terminal 3 is higher than the full charge voltage, the microcomputer 7 causes the transistor Tr ₁
Only this is turned on, and supplementary charging is performed with a charging current of about 30% of the charging current for rapid charging so as to supplement the electric power lost due to self-discharge during the charging suspension of the storage battery 11.

Here, a charging control procedure by the microcomputer 7 will be described.

As shown in FIG. 2, first, the rapid charging time Ta, the charging suspension time Tb, and the auxiliary charging time Tc are set (S1), and the storage battery is set.
When 11 is inserted between the charging terminals 3 and 6, the comparator 4 detects the uncharged state of the storage battery 11 due to the voltage drop of the charging terminal 3 (S2). When the uncharged state of the storage battery 11 is detected, Tr ₁
· Tr ₂ is turned ON quick charge is carried out (S3), the quick charge is determined whether being performed time Ta (S4).

In S3, if the rapid charging is not performed for the time Ta, the rapid charging is continuously performed, while if the rapid charging is performed for the time Ta, Tr ₁ and Tr ₂ are turned off and the charging is stopped (S5). Is maintained for a time Tb (S6). In S6, if the charging suspension is not maintained, it is continuously maintained, while if the charging suspension is maintained for the time Tb, the comparator 5 determines the terminal voltage of the storage battery 11 (S7).
In S7, if the terminal voltage of the storage battery 11 has not reached the full charge voltage, the process returns to S3 and rapid charging is performed again.On the other hand, if the terminal voltage of the storage battery 11 is equal to or higher than the full charge voltage, only Tr ₁ turns ON. Supplementary charge is performed (S8), and it is determined whether or not this supplementary charge is performed at time Tc (S9). In S9,
If the supplementary charge has not been performed for the time Tc, the supplementary charge is continuously performed. On the other hand, if the supplementary charge is performed for the time Tc, the charging of the storage battery 11 ends (S10).

In the present embodiment, one storage battery 11 is charged, but when a plurality of storage batteries 11 are charged in series, the charging voltage differs depending on the number of storage batteries 11, so comparison is made accordingly. It is necessary to set the reference voltage of the units 4 and 5.

[Embodiment according to claim 2] An embodiment according to claim 2 of the present invention is shown in Figs.
It will be described below with reference to the drawings.

The members having the same functions as those of the embodiment according to claim 1 are designated by the same reference numerals, and the description thereof will be omitted.

In the charger shown in this embodiment, auxiliary charging control means is added to the microcomputer 7 shown in FIG.

The auxiliary charging control means drives Tr ₁ and Tr ₂ so as to alternately repeat the rapid charging and the charging suspension for each predetermined time, and when the preset number of repetitions is reached, the repetition is stopped and Tr ₁ Only by turning it on, supplementary charging is performed for a predetermined time. The number of repetitions is set in consideration of the magnitude of the charging current supplied to the storage battery 11 at the time of rapid charging, the time for performing the rapid charging and the charging suspension, and the like so that the battery is almost fully charged when the repetition is completed. It
In this way, the auxiliary charging control means operates so as to repeatedly perform the rapid charging and the charging suspension for a predetermined number of times, so that the terminal voltage of the storage battery 11 becomes the full charge voltage by the comparator 5 during the charging suspension. Even if it is determined that it has not reached, supplementary charging is performed.

Here, a charging control procedure by the microcomputer 7 will be described.

As shown in FIG. 3, first, the rapid charging time Ta, the charging suspension time Tb, and the supplementary charging time Tc are set together with the number of times the rapid charging and the charging suspension are repeatedly performed (S11).
Is inserted between the charging terminals 3 and 6, the comparator 4 detects the uncharged state of the storage battery 11 due to the voltage drop of the charging terminal 3 (S12). When the uncharged state of the storage battery 11 is detected, Tr ₁
Tr ₂ turns on and quick charge is performed (S13)
It is determined whether Ta is being performed (S14).

In S13, while continuing rapid charging if rapid charging is not being performed time Ta is performed, the quick charge is carried out time Ta, Tr ₁ · Tr ₂ is charged to OFF is paused (S15), the charging suspension It is determined whether or not is maintained for time Tb (S16). In S16, if the charging suspension is not maintained, it is continuously maintained, while if the charging suspension is maintained for the time Tb, the comparator 5 determines the terminal voltage of the storage battery 11 (S1
7) If the terminal voltage of the storage battery 11 is higher than the full charge voltage, S
After shifting to 19, only Tr ₁ is turned on and auxiliary charging is performed. In S17, if the terminal voltage of the storage battery 11 has not reached the full charge voltage, it is determined whether or not the repetition of rapid charging and charging suspension has reached the set number of times (S18). That is, in S18, it is determined whether or not the repetition of the rapid charging and the charging suspension is ended, and if the repetition is not completed because the set number of times is not reached, the process returns to S13 and the rapid charging is performed.

On the other hand, when the repetition of the rapid charging and the charging suspension is completed in S18 after reaching the set number of times, the process proceeds to S19, supplementary charging is performed, and it is determined whether or not this supplementary charging is performed for the time Tc (S20). In S20, if the supplementary charge has not been performed for the time Tc, the supplementary charge is continuously performed. On the other hand, if the supplementary charge is performed for the time Tc, the charging of the storage battery 11 ends (S2
1).

[Effect of device]

The charger according to claim 1 of the present invention is as described above.
A charging current generating unit that generates a charging current to be supplied to the storage battery, a charging current supplying unit that supplies the charging current generated by the charging current generating unit to the storage battery, and a charging current supply unit are operated to rapidly charge the storage battery. The rapid charging means for performing the time, the charging suspension means for stopping the operation of the charging current supply means and stopping the charging of the storage battery for a predetermined time when the rapid charging by the rapid charging means is completed, and the charging current supply means for operating the supplementary battery. A supplementary charging means for charging for a predetermined time, a terminal voltage determination means for determining whether the terminal voltage of the storage battery is higher than a predetermined level or lower than a predetermined level immediately before the termination of the charging suspension by the charging suspension means, and the terminal voltage determination means. When the terminal voltage of the storage battery is determined to be lower than the predetermined level, the quick charging means is selected, while it is determined to be higher than the predetermined level A configuration in which a charge selecting means for charging the battery by selecting the supplemental charging means when.

As a result, the charging suspension means suspends charging, and the terminal voltage determination means determines the terminal voltage of the storage battery immediately before the termination of the charging suspension, so that the charging current is not supplied to the storage battery and the terminals of the storage battery are charged. The voltage drop caused by the contact resistance with the charging terminal of the battery is only due to the current flowing when the storage battery self-discharges,
It is almost negligible.

Therefore, it is possible to accurately determine the terminal voltage of the storage battery, prevent overcharging and undercharging, and achieve efficient charging.

Further, the charger according to claim 2 includes auxiliary charging control means for performing auxiliary charging by the auxiliary charging means when rapid charging by the rapid charging means and charging suspension by the charging suspension means are repeated a predetermined number of times. This is the configuration provided.

Thereby, in addition to the above effects, since the auxiliary charging control means is provided, if the rapid charging and the charging suspension are repeated a predetermined number of times, the auxiliary charging is performed for a predetermined time, and the storage battery determines the number of repetitions of the rapid charging and the charging suspension. If you set it so that it will be almost fully charged at the end of repetition, it will be possible to prevent the storage battery from becoming overcharged by continuing to be charged even though it was fully charged during rapid charging. Has the effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing a structure of a charger, which is common to the embodiment according to the invention of claim 1 and the embodiment according to the invention of claim 2, and FIG. Is a flow chart showing a control procedure in the embodiment according to the first aspect of the invention, and FIG. 3 is a flow chart showing a control procedure in the embodiment according to the second aspect of the invention. 2 is a rectifying / stabilizing circuit (charging current generating means), 3 and 6 are charging terminals, 4 is a comparator, 5 is a comparator (terminal voltage determining means, charge selecting means), 7 is a microcomputer (quick charging means, Charging suspension means, auxiliary charging means, auxiliary charging control means), and Tr ₁ and Tr ₂ are transistors (charging current supply means).

Claims (2)

[Scope of utility model registration request] 1. A charging current generating means for generating a charging current to be supplied to a storage battery, a charging current supplying means for supplying the charging current generated by the charging current generating means to the storage battery, and a charging current supplying means for operating the storage battery. On the other hand, the rapid charging means for performing the rapid charging for a predetermined time, the charging suspension means for stopping the operation of the charging current supply means and stopping the charging of the storage battery for a predetermined time when the rapid charging by the rapid charging means is completed, and the charging current supply means are operated. A supplementary charging means for supplementary charging the storage battery for a predetermined time, and a terminal voltage determination means for determining whether the terminal voltage of the storage battery is higher than a predetermined level or lower than the predetermined level immediately before the termination of the charging suspension by the charging suspension means, When the terminal voltage determination means determines that the terminal voltage of the storage battery is lower than the predetermined level, the quick charging means is selected, while the predetermined level is selected. Charger, characterized in that it comprises a charging selecting means for charging the battery by selecting the supplemental charging means when it is determined that higher. 2. A supplementary charging control means for performing supplementary charging by the supplementary charging means when the rapid charging by the rapid charging means and the charging suspension by the charging suspension means are repeated a predetermined number of times. The charger according to claim 1.