JPH1014120A - Rechargeable battery charging method - Google Patents

Abstract

(57) [Problem] To accurately perform a charging operation of a lithium ion battery by program control. SOLUTION: In charging a secondary battery attached to an electronic device having a charging means, first, a charging voltage is output to a charging terminal of the charging means for a predetermined time, and after the predetermined time has elapsed, a charging voltage is applied. The presence or absence of a secondary battery is determined by measuring the voltage of the charging terminal in the absence of the battery, and further, after confirming that the secondary battery is attached, using a control method of charging the secondary battery, Charge the battery. If the output terminal voltage of the power supply AC adapter used for charging the secondary battery during charging is not within the predetermined range, the charging is automatically stopped and the regular AC adapter is connected. Until
The secondary battery is charged using a control method for maintaining the stopped state. [Effect] Whether the secondary battery is installed or not, the regular A
Whether or not the C adapter is connected can be determined by program control, thereby preventing a charging malfunction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for charging a secondary battery, particularly a lithium ion battery.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become more portable, there has been a demand for smaller batteries, higher capacities and recyclability, and lithium ion batteries have been used among secondary batteries to satisfy these requirements. It is becoming popular.

[0003] As a characteristic of this lithium ion battery, when the remaining amount of the battery falls below a certain level, 0 V is output to the output terminal of the battery. It is impossible to determine whether or not a lithium ion battery is installed.Therefore, conventionally, a detecting means such as a switch for detecting the presence or absence of a battery is provided, and the installation of the battery is confirmed based on the detection result. I've been charging.

However, the provision of the above-described detecting means in the electronic device leads to an increase in cost due to an increase in the number of parts and an increase in the number of assembling steps, and also from the viewpoint of the structural reliability and durability of the detecting means. However, there is a risk of causing a malfunction. In addition, when an incorrectly used AC adapter is used during charging, even if the charging is continued as it is, correct charging is not performed, and there is a possibility that the device may be damaged.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to determine whether or not a secondary battery, particularly a lithium ion battery, is present in electronic equipment without using a detecting means such as a switch. It is an object of the present invention to provide a method for judging whether or not the charging operation is performed, and performing a charging operation correctly.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in charging a secondary battery mounted on an electronic apparatus having a charging means, first, a predetermined charging terminal of the charging means is provided. The charging voltage is output, and after the predetermined time has elapsed, the voltage of the charging terminal is measured in a state where the charging voltage is not applied to determine the presence or absence of the secondary battery, and further, the secondary battery is mounted. Then, the secondary battery is charged using the charging control method.

If the output terminal voltage of the power supply AC adapter used for charging the secondary battery during charging is not within a predetermined range, the charging is automatically stopped and a regular AC adapter is used. Until is connected, the secondary battery is charged by using the control method of maintaining the stopped state, thereby solving the above-mentioned problem.

According to the present invention, whether or not a secondary battery is built-in can be determined by program control without using hardware such as a detection switch, and the lithium ion battery can be charged without malfunction. If a nonstandard AC adapter is connected, this is determined by program control.
The charging operation is stopped until a proper AC adapter is connected, so that damage to the electronic device can be prevented.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of a charging operation system for explaining a charging method of the present invention.
2 to 4 are flowcharts of the charging method of the present invention.

The meanings of the symbols used in FIGS. 2 to 4 are as follows. V _AC : AC adapter voltage level V _BAT : Battery terminal voltage level V ₁ : Minimum value of chargeable AC adapter voltage level V ₂ : Maximum value of chargeable AC adapter voltage level V ₃ : Battery terminal voltage to start charging Level V ₄ : Battery terminal voltage level for judging the presence or absence of a battery V ₅ : Minimum value of normal range of battery terminal voltage level during charging V ₆ : Maximum value of normal range of battery terminal voltage level during charging V ₇ : Charging The minimum value of the normal range of the AC adapter voltage level during the middle V ₈ : The maximum value of the normal range of the AC adapter voltage level during the charging V ₉ : The battery terminal voltage level judged to be fully charged T ₁ : The time of the trial charging T ₂ : this charging time T _3: checking cell sampling during charging, full charge detection check period T _4: Check cell sampling during charging, for checking full-charge detection, temporary charging O Time to F T _5: after the full charge detection, time to recharge for the press just in case

First, the charging operation is controlled by a central processing unit (hereinafter referred to as "CPU") 1 as shown in FIG. 1, and input ports A, B, and C of the CPU 1 are connected to an AC adapter, respectively. The presence / absence detection signal, the output voltage of the AC adapter, and the battery terminal voltage are input. Also, the control signal of the charging operation from the output port D is a secondary battery,
For example, it is applied to a charging circuit 2 for charging a lithium ion battery 3 to control a charging operation.

Next, the flow of the charging operation of the present invention will be described. First, it is determined whether or not the AC adapter is connected based on the output of the means for detecting the presence or absence of the AC adapter input to the input port A of the CPU 1 (reference numeral 10). If it is not connected, the process returns to the start. If it is connected, it is checked whether the nonstandard AC adapter detection flag is set (reference numeral 1).
1). If set, return to start.

Next, when this flag is not set, the voltage level of the voltage of the AC adapter input to the input port B of the CPU 1 can be charged, that is, V ₁ <V.
It determines whether or not the an _AC <V ₂ (reference numeral 12). If not, return to start.

If it is within the range, the charging circuit 2 is turned on by the instruction of the output port D of the CPU 1 to determine whether or not the lithium ion battery 3 is mounted (reference numeral 1).
3). Here the time of the charging circuit 2 ON lithium ion battery 3 until passage of T ₁ is charged (code 14).
This T ₁ is a time for trial charging, and may be an extremely short time. T ₁ after, to stop OFF the charging circuit 2 Charge (reference numeral 15).

After the charging circuit 2 is turned off to stop charging,
It is determined whether the voltage of the battery terminal voltage of the lithium-ion battery 3 input to the input port C of the CPU 1 is lower than a level at which full charge can be determined, that is, whether or not V _BAT <V ₃ (reference numeral 16). . If it exceeds, return to start without charging.

Next, whether the battery terminal voltage is higher than the level at which it is determined that the battery is mounted, that is, V
It is determined whether or not ₄ <V _BAT (reference numeral 17). If it is below, it is determined that the lithium ion battery 3 is not mounted, and the process returns to the start. If that is mounted to set the charging time T ₂ to timer A (reference numeral 18). Thereafter, the charging circuit 2 is turned on in response to an instruction from the output port D of the CPU 1 to start charging the lithium ion battery 3 (reference numeral 19).

Next, either not withdrawn battery, also must be turned OFF to charge with a constant period in order to check such or not fully charged, the period T ₃
Is set in the timer B (reference numeral 20).

Next, whether the battery terminal voltage during charging is within the normal range, i.e., it is determined whether or not the _{V 5 <V BAT <V 6} ( reference numeral 21). If it is out of the range, stop charging and return to start. If the voltage is within the normal range, the voltage of the AC adapter is not lower than the normal range, that is, V ₇ <
It determines whether or not the a V _AC (reference numeral 22). If it is lower, it is regarded that an AC adapter of a nonstandard is connected, a detection flag is set (reference numeral 23), and the process returns to the start. Thereafter, until the AC adapter is unplugged, this flag is set, so that the determination at reference numeral 11 is added and the charging operation does not start again. This is because charging and stopping may be repeated during charging, and this oscillation is prevented.

If V ₇ <V _AC , A
Check if the C adapter voltage does not exceed the normal range,
Determines whether or not the a V _AC <V ₈ (reference numeral 24). If it exceeds, stop charging and return to start. If not, it is determined whether or not the timer A has overflowed (reference numeral 25). If the timer A overflows, it is determined that the time of the main charging has elapsed and the CPU 1
The charging circuit 2 is turned off (reference numeral 26) according to the instruction of the output port D, and the charging is terminated.

If timer A has not overflown, it is determined whether timer B has overflowed (reference numeral 27). If the timer B has not overflown, the process returns to the reference numeral 21. If the timer B overflows, it is time to check whether the battery is not removed or not fully charged,
For these checks, the charging circuit 2 is temporarily turned off according to the instruction of the output port D of the CPU 1 (reference numeral 28).

Next, in order to inspect the full charge withdrawn battery during charging and OFF between charging time T _4, after the T ₄ has elapsed (reference numeral 29), mounted battery terminal voltage level battery It is determined whether or not the level exceeds the level determined to be satisfied, that is, whether or not V ₄ <V _BAT (reference numeral 30). If not, it is determined that the battery is not mounted, and the process returns to the start. On the other hand, if the charge is exceeded, in order to reliably charge the battery, the battery is further charged after detecting full charge, and it is checked whether or not the battery is being recharged (reference numeral 3).
1). If recharging is being performed, all checks during charging are completed, and the process returns to reference numeral 19.

If the battery is not being recharged, it is determined that the battery terminal voltage level is higher than the level determined to be fully charged, that is,
It is determined whether or not V ₉ <V _BAT (reference numeral 32). Above back to the code 19 for charging again unless, whereas, regarded as if fully charged which exceeds returns to reference numeral 19 sets the time T ₅ the timer A, to re-charge for reminds ( Reference numeral 33).

By employing the above-described charging operation, even if the remaining amount of the lithium ion battery falls below a certain level and the output terminal is at 0 V, the presence or absence of the lithium ion battery is determined by charging the battery for a very short time. You can do it. In addition, when an AC adapter that is out of specification is connected, it is detected by checking the terminal voltage during charging, and the charging operation may be stopped until an AC adapter that is out of specification is connected. it can.

Note that the charging method of the present invention is not limited to being performed in accordance with the above-described program flow, but may adopt another program configuration that embodies the technical idea of the present invention. is there.

[0025]

As described above, according to the present invention,
Lithium-ion battery is a structure that is mounted in the electronic device, even if this battery can not be seen from outside the device, whether or not the battery is built-in, regardless of the hardware such as a detection switch, It can be determined instantaneously by program control. Therefore, it is possible to reduce the number of parts and improve the reliability.

Also, when a nonstandard AC adapter is connected, this is determined by program control, and a proper AC adapter is identified.
Stop charging operation until the adapter is connected to prevent damage to electronic devices.

[Brief description of the drawings]

FIG. 1 is a block diagram of a charging operation system for explaining a charging method of the present invention.

FIG. 2 is a flowchart of a charging method according to the present invention.

FIG. 3 is a flowchart following FIG. 2;

FIG. 4 is a flowchart following FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... CPU, 2 ... Charging circuit, 3 ... Lithium ion battery

Claims (3)

[Claims] In charging a secondary battery mounted on an electronic device having a charging means, first, a charging voltage is output to a charging terminal of the charging means for a predetermined time, and after a lapse of the predetermined time, a charging voltage is output. The voltage of the charging terminal is measured in a state where no voltage is applied to determine the presence or absence of a secondary battery, and further, after confirming that the secondary battery is mounted, a control method of performing charging is used. How to charge a secondary battery. 2. When an output terminal voltage of a power supply AC adapter used for charging a secondary battery during charging is not within a predetermined range, charging is automatically stopped and a regular AC power is supplied.
A charging method for a secondary battery, wherein charging is performed using a control method for maintaining a stopped state until an adapter is connected. 3. The method according to claim 1, wherein the secondary battery is a lithium ion secondary battery.