JPH09215221A - Battery charging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a battery charging method in which the contact failure of a terminal is eliminated and in which a charger can be miniaturized. SOLUTION: First, a constant charging current is supplied to a battery which is mounted and attached. Then, when the supply of the charging current is started, the voltage of the battery is measured at every prescribed time. After that, the time which elapses until the measured voltage of the battery reaches a predetermined voltage is computed. Then, the computed time and a predetermined reference time are compared. After that, on the basis of a comparison result, the capacity of the battery is judged. Then, on the basis of the judged capacity of the battery, the charging current is controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charging method for controlling charging by identifying a difference in battery capacity in a charger for charging a secondary battery as a power source for a mobile phone or the like. .

[0002]

2. Description of the Related Art FIG. 2 is a block diagram of a circuit of a conventional charger. Conventionally, two types of batteries (S-battery (small capacity) L-battery (S-battery (small capacity) L-battery ( Depending on the large capacity)), the method of controlling the charging current when charging is different. Therefore, it is necessary to identify the type of these batteries, and the SL detection terminal is provided in the charger for the identification. The SL detection terminal distinguishes between the S-battery and the L-battery depending on the presence or absence of the negative electrode terminal of the battery. The negative terminal of the battery is SL
The microcomputer determines that the L-battery is attached when it is in contact with the detection terminal and the S-battery is attached when it is not in contact with the SL detection terminal. In FIG. 2, T is a thermal sensor, which is a terminal used when measuring the temperature of the nickel hydrogen battery. Therefore, this terminal is not used for a nickel-cadmium battery or the like.

[0003]

However, as described above, in the conventional battery charging method using the charger, the charger is provided with the SL detection terminal, and the S-battery and the L-battery are connected in hardware.
Since the battery is distinguished from the battery, the provision of the SL detection terminal on the charger increases the possibility of poor contact between the terminal portion and the battery. In addition, since a space has to be secured for the SL detection terminal, there is a problem in that it is an obstacle to downsizing the charger.

Therefore, there has been a demand for a battery charging method capable of eliminating contact failure and downsizing the charger.

[0005]

SUMMARY OF THE INVENTION A battery charging method according to the present invention comprises a step of supplying a constant charging current to an installed battery, and a step of supplying the charging current to the battery to start charging the battery at predetermined intervals. The step of measuring the voltage, the step of calculating the time until the measured voltage reaches the predetermined voltage, the step of comparing the calculated time with the predetermined reference time, and the comparison result Based on the determined capacity of the battery, a step of controlling the charging current based on the determined capacity of the battery is included. The time required to reach a predetermined voltage is measured, and the capacity of the installed battery is detected based on the measured time. Even if there is no capacity detection terminal, it determines the type of battery and controls the charging current.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a flowchart of a battery identification and charging procedure according to an embodiment of the present invention. FIG.
FIG. 3 is a configuration block diagram according to an embodiment of the present invention. In FIG. 3, reference numeral 1 denotes a calculation control unit, which calculates or compares data such as input voltage, and gives instructions such as control of charging current. The memory unit 2 holds an operation program of the control unit and a reference value for comparison with measured values. In addition, the measured voltage value data of the battery and the like are also temporarily stored. Clock oscillator 5
Provides a timer with a periodic synchronization signal, and the timer counter 3 is about to count based on the signal of the clock oscillator 5. The display unit 9 is a place for visually teaching the user of the charging status and the like by means of LEDs or the like. A /
The D converter 4 is about to convert a signal to be sent to the display unit 9 or the like. The input / output port 6 is where the data inside and outside the microcomputer is connected. 7 is a charging terminal. The charging current supply unit 8 is a place where electric charges are supplied to the battery according to an instruction from the calculation control unit 1. The charge supplied by the instruction of the arithmetic control unit 1 is controlled. In addition,
In the present embodiment, the battery (battery pack) used for charging is three nickel hydrogen batteries connected in series, and each comparison value is based on that.

Next, a battery identification and charging procedure will be described with reference to FIG. When the arithmetic control unit 1 determines that the battery is attached to the charging terminal 7 based on the voltage change (S1), the battery voltage V
The measurement of b is started (S2). The charger is in the pre-charging mode, and the calculation control unit 1 has the battery voltage Vb of 0.6V.
It is determined whether or not it is above (S3). If Vb is 0.6V
If it is smaller, it is determined that there is an abnormality due to poor contact of the battery or initial failure of the battery (S4), and the charging is terminated without being performed. When it is determined that Vb is 0.6 V or more, the charging is set (S5), the LED of the display unit 9 is lit and displayed, and it is instructed to start charging (S6). Next, the arithmetic control unit 1 determines whether or not the battery voltage Vb is within the range of 3.5 <Vb <5.4 which is the normal range of the battery voltage (S7). If Vb is within this range, charging is started (S8). If Vb is not within this range, it is determined that the battery is abnormal (S9), and charging is terminated. In this case, the display unit 9
Is displayed in some form, it can be distinguished from the battery abnormality of S1.

Within the range of 3.5 <Vb <5.4, the voltage Vb
If the arithmetic control unit 1 determines that there is a Vb of 4.5,
It is determined whether or not Vb is within the range of <Vb <5.4 (S10), and if Vb is within the range, there is a large amount of charge stored in the battery when the battery is attached, When it is determined that the battery voltage is high, the charging current supply unit 8 is instructed to adjust the current flowing to the charging terminal 7 to start trickle charging (S1).
1). Trickle charging is to send a current smaller than the charging current that is normally supplied to a battery for charging. When trickle charging, it is not necessary to distinguish between different battery capacities.

At S10, Vb is 4.5 <Vb <
When it is not within the range of 5.4, it is determined whether it is within the range of 3.5 <Vb <3.6 (S12). If it is not within this range, that is, if the voltage Vb is within the range of 3.6 ≦ Vb ≦ 4.5, it means that some electric charge still remains in the battery. In this case, the time required for Vb to rise by 0.1 V is TiM (min), and its initial value is TiM = 0 (S13). Since the voltage of the battery being charged and the time due to a constant charging current are in a substantially proportional relationship, how much time it takes for the voltage Vb of the battery to rise by 0.1 V is determined as the measured voltage. It is calculated from the rate of change over time. The voltage and time are measured several times to calculate TiM, and if the range is 0 <TiM <10 (S14), the arithmetic control unit 1 determines that the attached battery is the S-battery ( S15). If TiM is within the range of 10 ≦ TiM <20 (S
16), it is determined that the attached battery is an L-battery (S17), and the charging current supply unit 8 is instructed,
The charging current is controlled (S18). If TiM is 20
If it is above, it is judged that the battery is abnormal (S
19) and terminates charging.

At S11, the voltage Vb is 3.5 <Vb
If it is determined to be within the range of <3.6, the charging current value Io is measured. When Io ≧ 1A (S20), the arithmetic control unit 1 determines that the flowing current is too large, and forcibly terminates the charging because there is an abnormality in the power supply (S2).
1). When Io is less than 1 A, the time until Vb becomes 4.5 V is TIM (min), and its initial value is T
IM = 0 is set (S22). Since the voltage of the battery and the time during charging with a constant charging current are in a substantially proportional relationship, it is determined how long it takes for the battery voltage Vb to reach 4.5V. And calculated from the rate of change of time. If the time until Vb becomes 4.5 V is TIM (min), TIM becomes 0 <
If it is in the range of TIM <50 (S23), the arithmetic control unit 1
Determines that the attached battery is an S-battery (S24). In addition, TIM is 50 ≦ TIM <16
If it is in the range of 0 (S25), the arithmetic control unit 1 determines that the attached battery is the L-battery, and (S25).
26), the charging current is controlled (S27). TIM is 1
If it is 60 or more, it is determined that the battery is abnormal (S28), and charging is terminated.

The arithmetic and control unit 1 gives an instruction to the charging current supply unit 8 according to the judged battery capacity, controls the current supply, and performs charging (S29). Since the battery has a characteristic that the voltage decreases when the battery is fully charged, if a negative value is detected in the voltage change, the arithmetic control unit 1 determines that the battery is fully charged (S30) and completes the charging (S31). ), The LED of the display unit 9 is turned off (S32), and the operation of the charger is terminated. If the voltage change is a positive value, the arithmetic control unit 1
Determines that the battery can still store charge and continues charging.

Embodiment 2. In addition, in the above-described embodiment, it is considered that three nickel-hydrogen batteries are connected in series as the secondary battery, but the present invention is not limited thereto and, for example, another secondary battery such as a nickel-cadmium battery. May be used, and the connection method is not limited. However, in that case, each condition value of the battery voltage Vb varies.

In the above embodiment, the charging current is controlled according to the type of battery, but the present invention is not limited to this, and the charging time is controlled according to the type of battery. You may allow it.

Further, in the above-described embodiment, the display unit is turned on at the start of charging and turned off at the end of charging, but when an abnormality occurs, it blinks or changes colors. You can think of various patterns.

[0015]

As described above, according to the present invention, in a battery charger for a mobile phone or the like, the time required to rise to a predetermined voltage is measured, and the difference in battery capacity is determined based on the measured time. By making a determination, the type depending on the capacity of the battery can be identified even without the SL detection terminal of the charger. Therefore, the contact failure of the terminal can be eliminated. Further, it is not necessary to secure a space for the SL detection terminal in the charger, and the charger can be downsized.

[Brief description of drawings]

FIG. 1 is a flowchart of battery identification and charging according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional charger.

FIG. 3 is a configuration block diagram of a charger according to an embodiment of the present invention.

[Explanation of symbols]

 1 arithmetic control unit 2 memory unit 3 timer counter 4 A / D converter 5 clock oscillator 6 input / output port 7 charging terminal 8 charging current supply unit 9 display unit 10 microcomputer

Claims (3)

[Claims] 1. A step of supplying a constant charging current to a mounted battery, a step of measuring the voltage of the battery at predetermined time intervals when the supply of the charging current is started, and the measured battery. Calculating a time until the voltage of the battery reaches a predetermined voltage, comparing the calculated time with a predetermined reference time, and based on the comparison result, the capacity of the battery. And a step of controlling the charging current based on the determined capacity of the battery. 2. A step of supplying a constant charging current to a mounted battery, a step of measuring the voltage of the battery at predetermined time intervals when the supply of the charging current is started, and the measured battery. The step of calculating the time required for a constant voltage change based on the voltage of, the step of comparing the calculated time with a predetermined reference time, and the capacity of the battery based on the comparison result. And a step of controlling the charging current based on the determined capacity of the battery. 3. A step of measuring an initial voltage value of a mounted battery, a step of supplying a charging current to the battery if the initial voltage value is within a predetermined range, and a step of supplying a charging current. When started, the step of measuring the voltage of the battery at predetermined time intervals is compared with the initial voltage value and a predetermined first voltage value, and the initial voltage value is calculated from the first voltage value. Is higher, the step of controlling the charging current such that trickle charging is performed; and, if the initial voltage value is less than or equal to the first voltage value, the initial voltage value and a predetermined second voltage value. If the initial voltage value is higher than the second voltage value, the time required for constant voltage change is calculated based on the measured voltage of the battery, and the time is determined in advance. Be Based on the result of comparison with the time of the first reference, determine the type by the capacity difference of the battery, and if the initial voltage value is equal to or less than the second voltage value, the measured voltage, The time required to reach a predetermined voltage is calculated, and the time required to reach the predetermined voltage is compared with a predetermined second reference time, based on the result of the battery capacity difference. It has a step of determining the type, a step of controlling the charging current of the battery based on the type due to the capacity difference of the battery, and a step of ending the charging when the voltage change of the battery becomes negative. And how to charge the battery.