JPH08308128A - Battery charger - Google Patents

Abstract

PURPOSE: To provide a battery charger the charging capacity of which can always be maintained at a prescribed value or higher. CONSTITUTION: When a secondary lithium ion battery 14 is charged, a timer means 11 and battery voltage detecting means 12 are actuated and the timer means 11 measures a prescribed period of time until the battery 14 is to be recharged after the battery 14 is charged. The detecting means 12 detects the charged voltage of the battery 14. When the timer means 11 detects the elapse of the prescribed time or the detecting means 12 detects that the voltage of the battery 14 drops from a preset prescribed value, a charge control means 10 executes the recharging of the battery 14 and a displaying means 13 displays the charged state of the battery 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device for charging, for example, a lithium ion secondary battery.

[0002]

2. Description of the Related Art Conventionally, in this type of charging device, in order to make up for a shortage of battery capacity due to spontaneous discharge after the end of charging, recharging is performed after a lapse of a certain period of time.

[0003]

However, in the above-mentioned conventional charging device, since recharging is not performed until a fixed time elapses after the charging is completed, the recharging is performed until the recharging is performed. In addition, there is a problem that when the current is consumed due to an incoming call from an outside line or the like, the charge capacity of the secondary battery becomes lower than a specified value.

The present invention has been made in view of the current state of the charging device of this type as described above, and an object thereof is to provide a charging device capable of always maintaining a charging capacity at a predetermined value or more. Especially.

[0005]

In order to achieve the above object, the invention according to claim 1 is a timer means for measuring a predetermined time from the end of charging until recharging, and the voltage of the charged secondary battery. Whether the predetermined time has elapsed is detected by the battery voltage detecting means for detecting the above, or the voltage of the secondary battery has become equal to or lower than a preset predetermined voltage by the battery voltage detecting means. Is detected,
A control means for recharging the secondary battery.

[0006] Similarly, in order to achieve the above object, the invention according to claim 2 is characterized in that, in addition to the invention according to claim 1, display means for indicating the charging state of the secondary battery is provided. It is what

[0007]

In the invention described in claim 1, when the charging of the secondary battery is completed, the timer means and the battery voltage detecting means operate,
The timer means measures a predetermined time from the end of charging until recharging, and at the same time, the battery voltage detecting means detects the voltage of the charged secondary battery.

When the timer means detects the passage of a predetermined time or the battery voltage detecting means detects that the voltage of the secondary battery has become equal to or lower than a preset predetermined voltage, the control means Recharges the secondary battery.

According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, the charge state of the secondary battery is displayed by the display means.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
Will be described with reference to.

FIG. 1 is a block diagram showing the configuration of this embodiment,
FIG. 2 is a time chart showing the charging operation of this embodiment.

In the present embodiment, as shown in FIG. 1, a lithium-ion secondary battery 14 to be charged is connected to a charging device 15, and the charging device 15 indicates to a charging control means 10 for controlling a charging operation after charging. Timer means 11 for counting the time of
The battery voltage detection means 12 for detecting the battery voltage of the lithium ion secondary battery 14 connected to the charging device 15 is connected. Similarly, the charging control means 10 is connected to a lithium ion secondary battery 14 to be charged and a display means 13 for displaying the charging state of the lithium ion secondary battery 14.

The operation of this embodiment having such a configuration will be described. In the present embodiment, the timer means 11 and the battery voltage detection means 12 are activated from the time when the charging of the lithium ion secondary battery 14 is completed, and the timer means 11 counts the time after completion of the charging to obtain the battery voltage. The voltage of the lithium-ion secondary battery 14 is detected by the detecting means 12, and the time signal from the timer means 11 is detected by the battery voltage detecting means 12
A voltage signal is input to the charging control means 10.

The lithium-ion secondary battery 14 is the charging device 1.
5, the charging control means 10 is started when charging is started.
When the voltage of the lithium-ion secondary battery 14 reaches 4.1 V, the display unit 13 is instructed to display “charging” by the command of No. 1, and when the voltage of the lithium ion secondary battery 14 reaches 4.1 V, the display unit 13 is instructed by the command of the charge control unit 10. A display of "full charge" indicating that the battery 14 has been charged is displayed.

From this charging completed state, when the lithium ion secondary battery 14 is used to consume a large amount of current due to an incoming external call or the like, the battery voltage detecting means 12
The voltage of the lithium-ion secondary battery 14 detected by means of a relatively steep drop as indicated by the characteristic line A in FIG. 2 and reaches the specified voltage of 3.9 V at time T1. When the detected value of the battery voltage by the battery voltage detection means 12 reaches 3.9V, the charging control means 10 starts recharging the lithium-ion secondary battery 14, and the display means 13 displays "charging". And the lithium-ion secondary battery 14
The voltage rises as indicated by the characteristic line A from time T2. Then, at time T2, the voltage of the lithium ion secondary battery 14 reaches 4.1 V and the recharging is completed, and the display unit 13 displays "full charge" according to the command from the charging control unit 10.

On the other hand, when the lithium ion secondary battery 14 discharges without consuming a large amount of current, the voltage of the lithium ion secondary battery 14 detected by the battery voltage detecting means 12 has the characteristics shown in FIG. A time signal indicating that the predetermined 6 hours have elapsed from the timer means 11 is input to the charging control means 10 at the time T3 as the line B decreases with a relatively gentle slope. By inputting this time signal, the lithium ion secondary battery 14 is recharged by the charging control means 10, the lithium ion secondary battery 14 is recharged along the characteristic line B from time T3, and the lithium ion secondary battery 14 is recharged at time T4. The recharge of the secondary battery 14 is completed. In this case, the display of the "full charge" is continued on the display unit 13 according to the instruction of the charge control unit 10.

As described above, according to this embodiment, the battery voltage detecting means 12 and the timer means 11 are connected to the charge control means 10.
The charging capacity of the lithium-ion secondary battery 14 can be constantly maintained at a certain value or more against the decrease in battery voltage due to current consumption and the decrease in battery voltage due to spontaneous discharge.

Incidentally, in FIG. 2, a characteristic line C indicated by a dotted line indicates a conventional charging operation, and conventionally, since recharging is not performed until the time T3 is reached, the lithium ion secondary battery 14 is charged at the battery voltage. Existed for a period of 3.9 V or less.

In this embodiment, the case where the lower limit battery voltage of the lithium ion secondary battery is 3.9 V and the predetermined discharge time is 6 hours has been described, but the present invention is not limited to this embodiment. .

[0020]

According to the invention described in claim 1, when the charging of the secondary battery is completed, the timer means and the battery voltage detecting means are activated, and the timer means causes the predetermined time from the end of the charging until the recharging. Measured, at the same time, the battery voltage detection means detects the voltage of the charged secondary battery, the timer means detects the passage of a predetermined time, or the battery voltage detection means detects the voltage of the secondary battery, When it is detected that the voltage becomes equal to or lower than the predetermined voltage set in advance, the control means recharges the secondary battery, so that the charge capacity of the secondary battery can be always maintained at the predetermined value or more. Become.

According to the invention of claim 2, in addition to the effect obtained by the invention of claim 1, by the display means,
Since the charge state of the secondary battery is displayed, the operator can accurately grasp the current charge state of the secondary battery.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a charging operation of the same embodiment.

[Explanation of symbols]

 10 Charge Control Means 11 Timer Means 12 Battery Voltage Detecting Means 13 Display Means 14 Lithium Ion Secondary Battery 15 Charging Device

Claims (2)

[Claims] 1. A timer means for measuring a predetermined time from the end of charging until recharging, a battery voltage detecting means for detecting a voltage of a charged secondary battery, and the timer means for determining whether or not the predetermined time has elapsed. And a control means for recharging the secondary battery when detected or when the battery voltage detecting means detects that the voltage of the secondary battery becomes equal to or lower than a preset predetermined voltage. Charging device characterized by. 2. The charging device according to claim 1, further comprising display means for indicating a charging state of the secondary battery.