JPH05207671A - Charger - Google Patents

Abstract

PURPOSE:To perform suitable auxiliary charging by providing battery temperature detecting means, calculating means, timer means and switch means. CONSTITUTION:A temperature detecting resistor 7 detects a temperature of a storage battery 3, and outputs a signal corresponding to the temperature to an arithmetic circuit 8. The circuit 8 stores a self-discharging amount per unit time of the battery 3, i.e., the temperature characteristics of self-discharging ratio. Accordingly, the circuit 8 calculates the temperature of the battery 3 from the input signal, and calculates a self-discharging ratio at the temperature. The circuit 8 inputs a signal corresponding to a sequential battery temperature, integrates the self-discharging ratio at this time while sequentially calculating it, and outputs a signal for operating a timer 9 when the integrated value reaches a predetermined value. Thus, the timer 9 closes switches 4, 5 for a predetermined time to auxiliarily charge the battery 3. In this manner, it can be suitably auxiliarily charged in response to a variation in the environmental temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device, and more particularly to a charging device for supplementing the self-discharge of a storage battery.

[0002]

2. Description of the Related Art Conventionally, it has been known that batteries such as nickel-cadmium batteries and nickel-hydrogen batteries self-discharge when left standing. It is also known that the self-discharge amount of such a battery varies depending on the standing temperature. For this reason, even if the battery is fully charged, if the battery is left as it is, the battery will self-discharge and the capacity at the time of full charge cannot be obtained. Therefore, when the battery is left to stand after being fully charged, it is necessary to appropriately supplement the self-discharge.

By the way, a number of storage battery charging devices have been developed. For example, the one disclosed in Japanese Utility Model Application Laid-Open No. 2-104740 determines whether the terminal voltage of the storage battery is equal to or higher than a reference voltage, and if the terminal voltage is equal to or lower than the reference voltage, performs rapid charging for a certain period of time and then trickle charges the same. It was designed to be switched. This charger charges the storage battery to near full charge in a short time by quick charging, and then performs supplementary charging by trickle charging. A charging method that combines such quick charging and trickle charging is
There is a feature that the storage battery can be charged in a short time by the quick charge and the fully charged state of the storage battery can be maintained by the trickle charge. However, if trickle charging is continuously performed after rapid charging, the storage battery may be overcharged and deterioration of the storage battery may occur. On the other hand, a charging device has been developed in which a timer means is provided for trickle charging and the trickle charging is stopped after a predetermined time. is there.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a charger for supplementing the self-discharge of a storage battery.

[0005]

According to the present invention, there is provided temperature detecting means for detecting a battery temperature, arithmetic means for successively inputting the output of the temperature detecting means, and timer means for operating by receiving the output of the arithmetic means. It comprises switch means for turning on / off the charging of the battery by the output of the timer means, and the arithmetic means integrates the output of the temperature detecting means as a self-discharge amount per unit time according to the battery temperature, and the self-discharge amount is a predetermined value. The timer means is actuated when the temperature reaches, and the timer means turns on the switch means for a predetermined time to perform auxiliary charging of the battery.

[0006]

The present invention operates as follows. That is, the temperature detecting means detects the battery temperature. The temperature detecting means outputs a signal according to the battery temperature to the calculating means. The temperature characteristic of the self-discharge amount of the storage battery per unit time, that is, the self-discharge rate is stored in advance in the calculation means. Therefore, the calculation means calculates the battery temperature of the storage battery from the input signal and calculates the self-discharge rate at that temperature. Further, the calculating means is adapted to successively input a signal corresponding to the battery temperature, and the calculating means integrates while sequentially calculating the self-discharge rate at this time. When the integrated amount reaches a predetermined value, a signal for activating the timer means is output. The timer means turns on the switch means for a predetermined time to perform supplementary charging of the battery.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 1, reference numeral 1 is a commercial AC input from a household outlet. Reference numeral 2 is a charging power source, which converts commercial alternating current into a desired charging current. 3 is a nickel hydrogen battery as a battery to be charged. Further, 4 and 5 are changeover switches connected in parallel with each other between the charging power source 2 and the nickel hydrogen battery 3. A current limiting resistor 6 is connected in series to the changeover switch 5. Therefore, when the changeover switch 4 is closed, a quick charging current is supplied from the charging power source 2 to the nickel hydrogen battery 3 through the changeover switch 4, and when the changeover switch 5 is closed,
A trickle charging current is supplied from the charging power source 2 to the nickel hydrogen battery 3 via the changeover switch 5 and the current limiting resistor 6. Reference numeral 7 is a temperature detecting resistor, which is arranged close to the nickel hydrogen battery 3 to detect the battery temperature. On the other hand, 8 is an arithmetic circuit, which inputs the output of the temperature detecting resistor 7 and the charging voltage of the nickel hydrogen battery 3, respectively. The output of the arithmetic circuit 8 is connected to the changeover switch 4 and the timer 9,
The output of the timer 9 is connected to the changeover switch 5.

Now, the operation of the charging device according to the present invention having the above structure will be described. When the charging device of the present invention is connected to a commercial AC and the nickel hydrogen battery 3 is set, the arithmetic circuit 8 detects the battery voltage of the nickel hydrogen battery 3.
When the remaining capacity of the battery is low and the battery voltage is low, the arithmetic circuit 8 outputs a signal to the changeover switch 4, the changeover switch 4 is closed, and rapid charging is started. The battery voltage rises when the rapid charge progresses and eventually approaches the full charge. When the battery voltage reaches a predetermined value, the arithmetic circuit 8 determines that the nickel-hydrogen battery 3 has reached full charge, outputs a signal for opening the changeover switch 4, and charging is completed.

When charging is completed, the nickel-hydrogen battery 3 is disconnected from the charging circuit and left in a standing state. The nickel-hydrogen battery 3 starts self-discharging when it is left unattended for a long period of time, but the supplementary charging which is the gist of the present invention to supplement this self-discharging will be described with reference to the flowchart of FIG. When the charging is completed, the arithmetic circuit 8 inputs the output of the temperature detecting resistor 7 and sequentially reads the battery temperature. Here, the arithmetic circuit 8 stores the temperature characteristic of the self-discharge amount per unit time of the nickel-hydrogen battery, that is, the self-discharge rate, as shown in FIG. Therefore, the arithmetic circuit 8 calculates the battery temperature from the output of the temperature detecting resistor 7 and calculates the self-discharge rate at that temperature. The calculating means 8 integrates while sequentially calculating the self-discharge rate at this time. When the integrated amount, that is, the self-discharge amount reaches a predetermined value, a signal for operating the timer 9 is output. The timer 9 closes the changeover switch 5 for a predetermined time, and the supplementary charging of the nickel hydrogen battery 3 is started. This supplementary charging is trickle charging in which the current limiting resistor 6 limits the current. Trickle charging is continued for a predetermined time to supplement the self-discharge amount. After a lapse of a predetermined time, the changeover switch 5 is opened and the nickel hydrogen battery 3 is disconnected from the charging circuit. Then, the calculating means 8 successively reads the battery temperature again, and this supplementary charging is repeated.
Therefore, as shown in FIG. 4, after the nickel-hydrogen battery 3 reaches full charge by rapid charging, the state of leaving and the supplementary charging for compensating for the amount of self-discharge generated in the state of leaving are repeatedly performed.

[0010]

As described above, the gist of the charging device according to the present invention is that the temperature detecting means for detecting the battery temperature, the calculating means for successively inputting the output of the temperature detecting means, and the output of the calculating means are inputted. The operation means integrates the output of the temperature detection means as a self-discharge amount per unit time according to the battery temperature, and the switch means for turning on / off the charging of the battery by the output of the timer means. However, when the self-discharge amount reaches a predetermined value, the timer means is activated, and the timer means turns on the switch means for a predetermined time to perform supplementary charging of the battery. Even if a certain storage battery self-discharges, when the self-discharge amount reaches a predetermined value, supplementary charging is performed as appropriate, so the capacity at full charge can always be obtained when used for driving electrical equipment. That. In addition, by detecting the temperature of the storage battery, it is possible to perform supplementary charging that compensates for this self-discharge according to the temperature characteristics of the self-discharge rate, and it is also possible to perform appropriate supplementary charging in response to changes in ambient temperature. It can be done.

[Brief description of drawings]

FIG. 1 is a block circuit diagram.

FIG. 2 is a flowchart for supplementary charging.

FIG. 3 is a temperature characteristic diagram of a self-discharge amount of a nickel hydrogen battery.

FIG. 4 is a diagram showing changes over time in battery voltage and charging current.

[Explanation of symbols]

 1 Commercial AC 2 Power supply for charging 3 Nickel metal hydride battery 4 Changeover switch 5 Changeover switch 6 Current limiting resistance 7 Temperature detection resistance 8 Arithmetic circuit 9 Timer

Claims (1)

[Claims] 1. A temperature detecting means for detecting a battery temperature, an arithmetic means for successively inputting the output of the temperature detecting means, a timer means for operating by inputting the output of the arithmetic means, and an output of the timer means for outputting to the battery. The calculation means integrates the output of the temperature detection means as a self-discharge amount per unit time according to the battery temperature, and the timer means when the self-discharge amount reaches a predetermined value. And the timer means turns on the switch means for a predetermined time to perform supplementary charging of the battery.