JP3036943B2 - Charging device - Google Patents

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 performing supplementary charging for supplementing self-discharge of a storage battery.

[0002]

2. Description of the Related Art Conventionally, batteries such as nickel-cadmium batteries and nickel-metal hydride batteries have been known to self-discharge when left unattended. It is also known that the self-discharge amount of such a battery varies depending on the storage temperature. Therefore, even if the battery is fully charged, there is a problem that if the battery is left after that, the battery will self-discharge, and the capacity at the time of full charge cannot be obtained. Therefore, when the battery is left after being charged to a full charge, it is necessary to appropriately supplement the self-discharge.

[0003] By the way, many charging devices for storage batteries have been developed conventionally. For example, Japanese Unexamined Utility Model Publication No. 2-104740 discloses a method of determining whether the terminal voltage of a storage battery is equal to or higher than a reference voltage. If the terminal voltage is equal to or lower than the reference voltage, quick charging is performed for a certain period of time. It is designed to be switched. This charger charges a storage battery to near full charge in a short time by quick charge, and then performs supplementary charge by trickle charge. A charging method combining such quick charging and trickle charging,
There is a feature that the storage battery can be charged in a short time by the rapid charging and a full charge state of the storage battery can be maintained by the trickle charging. However, if trickle charging is performed continuously after rapid charging, the storage battery may eventually be overcharged, leading to deterioration of the storage battery. On the other hand, a charging device that provides timer means for trickle charging and stops trickle charging after a predetermined time has been developed. is there.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a charger for performing supplementary charging for supplementing self-discharge of a storage battery.

[0005]

SUMMARY OF THE INVENTION The present invention comprises a temperature detecting means for detecting a battery temperature, a calculating means for sequentially inputting an output of the temperature detecting means, a timer means for inputting an output of the calculating means and operating, Switch means for turning on / off the charging of the battery according to the output of the timer means; and the calculating 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 time has reached, and the timer means turns on the switch means for a predetermined time to carry out supplementary 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 corresponding to the battery temperature to the calculating means. The arithmetic means stores in advance the amount of self-discharge of the storage battery per unit time, that is, the temperature characteristics of the self-discharge rate. Therefore, the calculating means calculates the battery temperature of the storage battery from the input signal, and calculates the self-discharge rate at that temperature. The calculating means is adapted to sequentially 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 operating 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]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. In FIG. 1, reference numeral 1 denotes a commercial AC input from a household outlet. A charging power source 2 converts a commercial AC into a desired charging current. Reference numeral 3 denotes a nickel hydrogen battery as a battery to be charged. Reference numerals 4 and 5 are changeover switches connected in parallel between the charging power supply 2 and the nickel-metal hydride battery 3. A current limiting resistor 6 is connected to the changeover switch 5 in series. Therefore, when the changeover switch 4 is closed, the rapid charging current is supplied from the charging power source 2 to the nickel-metal hydride battery 3 via 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-metal hydride battery 3 via the changeover switch 5 and the current limiting resistor 6. Reference numeral 7 denotes a temperature detecting resistor which is arranged close to the nickel-metal hydride battery 3 to detect the battery temperature. On the other hand, reference numeral 8 denotes an arithmetic circuit for inputting the output of the temperature detecting resistor 7 and the charging voltage of the nickel-metal hydride 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 in the above configuration will be described. When the charging device of the present invention is connected to commercial AC and the nickel-metal hydride battery 3 is set, the arithmetic circuit 8 detects the battery voltage of the nickel-metal hydride 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, and the changeover switch 4 closes to start rapid charging. The battery voltage rises as fast charging progresses and nears full charge. When the battery voltage reaches a predetermined value, the arithmetic circuit 8 determines that the nickel-metal hydride battery 3 has reached full charge, outputs a signal to open the changeover switch 4, and ends charging.

When the charging is completed, the nickel-metal hydride battery 3 is disconnected from the charging circuit and is left unattended. The nickel-metal hydride battery 3 starts self-discharge when left unattended for a long period of time. Supplementary charge that supplements the self-discharge, which is the gist of the present invention, 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 self-discharge amount per unit time of the nickel-metal hydride battery as shown in FIG. 3, that is, the temperature characteristics of the self-discharge rate. 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 computing means 8 integrates the self-discharge rates at this time while sequentially calculating them. 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 auxiliary charging of the nickel-metal hydride battery 3 is started. This auxiliary charging is trickle charging in which the current is limited by the current limiting resistor 6. Trickle charging is continued for a predetermined time to compensate for the amount of self-discharge. After a lapse of a predetermined time, the changeover switch 5 is opened, and the nickel-metal hydride battery 3 is disconnected from the charging circuit. Thereafter, the calculating means 8 sequentially reads the battery temperature again, and this supplementary charge is repeated.
Therefore, as shown in FIG. 4, after the nickel-metal hydride battery 3 reaches the full charge by the rapid charging, the idle state and the supplementary charge for supplementing the self-discharge amount generated in the idle state are repeatedly performed.

[0010]

As described above, the gist of the charging device according to the present invention is as follows: temperature detecting means for detecting the battery temperature; calculating means for sequentially inputting the output of the temperature detecting means; and inputting the output of the calculating means. And a switch means for turning on / off the charging of the battery by the output of the timer means. The calculating means integrates the output of the temperature detecting means as a self-discharge amount per unit time according to the battery temperature. When the self-discharge amount reaches a predetermined value, the timer means is operated, and the timer means turns on the switch means for a predetermined time to perform supplementary charging of the battery. Even if self-discharge occurs in a certain storage battery, supplementary charging is performed appropriately when the self-discharge amount reaches a predetermined value, so that when used for driving electric equipment, etc., the capacity at full charge is always obtained. That. The auxiliary charge that compensates for the self-discharge can detect the temperature of the storage battery and perform the auxiliary charge in accordance with the temperature characteristics of the self-discharge rate. You can do it.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram.

FIG. 2 is a flowchart at the time of auxiliary charging.

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

FIG. 4 is a diagram showing a change over time of a battery voltage and a charging current.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Commercial alternating current 2 Charging power supply 3 Nickel-metal hydride battery 4 Changeover switch 5 Changeover switch 6 Current limiting resistor 7 Temperature detecting resistor 8 Arithmetic circuit 9 Timer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H02J ^7/ 00-7/12 H02J ⁷ /34-7/36

Claims (1)

(57) [Claims] A temperature detecting means for detecting a battery temperature; a calculating means for sequentially inputting an output of the temperature detecting means; a timer means for receiving an output of the calculating means to operate; The calculating means integrates the output of the temperature detecting means as a self-discharge amount per unit time according to the battery temperature, and when the self-discharge amount reaches a predetermined value, the timer means , And the timer means turns on the switch means for a predetermined time to perform supplementary charging of the battery.