JP2000316237A - Method for controlling charging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively obtain a charging controller which can execute charging of a battery to be charged with an arbitrary charging current, by variably adjusting the energizing pulse of the charging current so as to satisfy the charging duty corresponding to the potential difference between the voltage of the battery and an input charging voltage. SOLUTION: A control section 2 finds the potential difference between the voltage Vb of a secondary battery 1 to be charged and an input charging voltage Vin and outputs pulse-like ON/OFF control signals to a transistor Tr so as to satisfy the charging duty corresponding to the potential difference. When the battery 1 is to be charged quickly, the control section 2 starts charging with a very small charging current by outputting an ON/OFF control signal composed of a pulse having a short ON-time to the transistor at the charging starting time at which the potential difference between the voltages Vb and Vin is large. When the voltage Vb reaches a set value, the section 2 shifts the charging to quick charging using a large current by outputting another ON/OFF signal composed of a pulse having a long ON-time to the transistor Tr.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging control method for charging a battery to be charged, and more particularly to a charging control method capable of charging a battery with an arbitrary charging current.

[0002]

2. Description of the Related Art In general,
When charging a secondary battery, charging current is changed over time according to the voltage state of the secondary battery.

For example, before performing quick charging, it is predicted that a failure occurs due to some cause of a battery, and a very small current (C
/ 50 to C / 20), and when the battery voltage reaches the set voltage, rapid charging is performed with a current of about 0.5 to 1C.

Conventionally, a dedicated charge control controller has been used to perform such charging, but there has been a disadvantage that it is very expensive.

A transistor Tr as shown in FIG.
It has also been proposed to charge using a constant current circuit consisting of 1, Tr2 and resistors R1 and R2. However, the number of components such as transistors and resistors is large, the cost is high, and in order to change the charging current value, the circuit needs to be charged. There was a disadvantage that it was necessary to change the constant.

[0006] Further, it has been proposed to charge by using a forward constant current circuit comprising a diode D and a resistor R as shown in FIG. 3, but there is an advantage that the circuit is simple, but when the battery voltage fluctuates. There is a disadvantage that the charging current fluctuates and stable full charging cannot be performed.

The present invention has been made in view of these points, and a charge control method which can charge a battery to be charged with an arbitrary charge current by freely adjusting a charge current and at a low cost. And a charge control device.

[0008]

According to a first aspect of the present invention, there is provided a charge control method comprising: obtaining a potential difference between a battery voltage of a battery to be charged and a charging input voltage; The present invention is characterized in that the charging battery is charged with an arbitrary charging current by variably adjusting an energizing pulse for applying a pulse of the charging input voltage to the battery to be charged so as to satisfy a corresponding charging duty.

According to the present invention, the charging current can be freely adjusted by variably adjusting the energizing pulse, and the battery to be charged can be charged with an arbitrary charging current.

According to a second aspect of the present invention, there is provided a charge control device for controlling an energization state of supplying a charging input voltage to a battery to be charged, a battery voltage of the battery to be charged and a charging voltage. A control unit that obtains a potential difference from an input voltage and turns on / off the transistor in a pulsed manner so as to satisfy a charging duty according to the potential difference.

According to the present invention, the pulse for turning on / off the transistor is variably adjusted by the control unit, so that the charging current can be freely adjusted by applying the method of the present invention according to the first aspect of the present invention. To charge the battery to be charged.

[0012]

FIG. 1 is a block diagram showing an embodiment of the present invention.
Will be described.

FIG. 1 shows an embodiment of a charge control device according to the present invention.

In this embodiment, a secondary battery 1 to be charged is connected between terminals T1 and T2. A battery voltage Vb is obtained from one terminal T2 and detected by the control unit 2. Terminal T
A transistor Tr and a current limiting resistor R are connected in series to supply a charging current from 3 to a terminal T2. The input voltage Vin for charging is applied to the terminal T3, and its magnitude is detected by the control unit 2. ON / OFF from the control unit 2 to the base of the transistor Tr
A control signal is applied. This control unit 2
Calculates the potential difference between the battery voltage Vb of the secondary battery 1 and the input voltage Vin for charging, and sets a pulsed ON / O to the transistor Tr so as to satisfy the charging duty according to the potential difference.
It is formed to apply an FF control signal.

Hereinafter, the operation of the present embodiment will be described.

For example, a description will be given of the case of performing rapid charging. First, the control unit 2 calculates a potential difference between the battery voltage Vb of the secondary battery 1 and the input voltage Vin for charging. Predicting the occurrence of a failure of the secondary battery 1 due to some cause, it is determined that the charging duty is suppressed to a small value and the battery is charged with a very small current (0.1 C).
Apply the OFF control signal. As a result, the charging input voltage is applied to the secondary battery 1 in a pulsed manner, and charging with a minute charging current (0.1 C) is started.

The control unit 2 continuously detects a change in the battery voltage Vb of the secondary battery 1, and when the battery voltage Vb reaches the set voltage, increases the charge duty and rapidly charges with a charge current of about 1C. ON / OFF consisting of a pulse with a long ON time to the transistor Tr.
Apply control signal. Thereby, rapid charging of the secondary battery 1 with a large current (1 C) is started.

The control unit 2 continuously detects a change in the battery voltage Vb of the secondary battery 1 and applies an OFF signal to the transistor Tr when the battery voltage Vb reaches the full charge voltage to charge the battery. To end.

As described above, according to the present embodiment, the energizing pulse composed of the ON / OFF control signal for the transistor Tr is variably adjusted, so that the energizing pulse for the secondary battery 1 is variably adjusted, and the charging current is adjusted. Can be freely adjusted to charge the secondary battery with an arbitrary charging current.

It should be noted that the present invention is not limited to the above-described embodiment, but can be modified as needed.
For example, the charging current may be a constant current according to the state of the battery to be charged.

[0021]

As described above, according to the charging control method and the charging control device of the present invention, the potential difference between the battery voltage of the battery to be charged and the input voltage for charging is determined, and the charging is performed so as to satisfy the charging duty according to the potential difference. The input voltage is variably adjusted by applying a pulse to the battery to be charged, and the battery to be charged is charged with an arbitrary charging current. Therefore, the charging current is freely adjusted to provide an arbitrary charging current. Thus, it is possible to charge the battery to be charged, and it is possible to obtain excellent effects such as lower cost.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a charge control device of the present invention.

FIG. 2 is a conventional constant current circuit diagram.

FIG. 3 is a conventional forward constant current circuit diagram.

[Explanation of symbols]

 1 secondary battery 2 control unit Tr transistor

Claims (2)

[Claims] 1. A potential difference between a battery voltage of a battery to be charged and a charging input voltage is obtained, and an energizing pulse for applying a pulse to the battery to be charged with the charging input voltage so as to satisfy a charging duty according to the potential difference is determined. A charge control method comprising: variably adjusting the battery to be charged with an arbitrary charging current. 2. A transistor for controlling an energization state in which a charging input voltage is supplied to a battery to be charged, a potential difference between a battery voltage of the battery to be charged and a charging input voltage, and charging according to the potential difference is performed. A control unit for turning on / off the transistor in a pulsed manner so as to satisfy a duty.