JPH06141475A - Detecting method for battery in nonaqueous electrolyte battery charger - Google Patents

Abstract

PURPOSE:To cut down part cost and manufacture cost and surely detect a nonaqueous electrolyte battery with high reliability. CONSTITUTION:This method is one for charging the battery to fixed voltage in the final process of fully charging the battery, and fully charging it, and then, detecting the existence of a battery. A battery is detected by repeating the charge and pause of the battery at specified intervals after fully charging it, and detecting the battery voltage during pause. Since the existence of a nonaqueous electrolyte battery, where the charge current becomes almost zero, being fully charged, is judged by detecting the battery voltage at pause by repeating the charge and pause in this way, it can be detected accurately and, besides, with high reliability with an inexpensive circuit.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method of detecting whether a fully charged non-aqueous electrolyte battery has been removed from a charger.

[0002]

2. Description of the Related Art A non-aqueous electrolyte battery remarkably deteriorates in battery performance when overcharged. To prevent overcharging, when approaching full charge, constant current charging switches to constant voltage charging.
When a non-aqueous electrolyte battery is charged with a constant voltage, the charging current decreases as it approaches full charge, and almost no current flows when fully charged. The non-aqueous electrolyte battery having such charging characteristics cannot detect the presence or absence of the battery by detecting the charging current. This is because a fully charged non-aqueous electrolyte battery does not flow a charging current even when it is charged at a predetermined voltage. This state is the same as the state where no battery is set.

Therefore, the conventional charger cannot detect the presence or absence of a battery by an electrical method, but detects the presence or absence of a battery by a mechanical method. Pushbutton switches have been used to mechanically detect the presence or absence of a battery. The presence or absence of the battery can be detected by turning on the push button switch when the battery is set in the charger and turning off when the battery is taken out.

[0004]

As described above, the method of mechanically detecting the presence / absence of the battery has a drawback that the cost of the parts is increased because it is necessary to provide parts such as a push button switch in the charger. In addition, parts such as push button switches having mechanically movable parts are more likely to malfunction and lower in reliability than electrical sensors having no mechanically movable parts. Further, since a push button switch or the like is provided on the case of the charger, there are disadvantages that the number of assembling steps is large and the manufacturing cost is high.

The present invention was developed for the purpose of solving these drawbacks. The important object of the present invention is to
It is an object of the present invention to provide a battery presence / absence detection method for a non-aqueous electrolyte battery charger, which can reduce the component cost and the manufacturing cost and can reliably and reliably detect the presence / absence of a battery.

[0006]

The battery presence / absence detection method for a non-aqueous electrolyte battery charger according to the present invention detects the presence / absence of a battery in the following manner in order to achieve the above object. That is, the method of the present invention is an improved method of detecting the presence or absence of a battery after the battery is charged to a constant voltage in the final process of fully charging the battery and the battery is fully charged.

The method for detecting the presence / absence of a battery of the present invention is to charge the non-aqueous electrolyte battery to full charge, then repeatedly charge and suspend the battery at predetermined time intervals, detect the battery voltage during the suspension, and detect the non-aqueous electrolyte solution. It is characterized by detecting the presence or absence of a battery.

[0008]

The battery presence / absence detection method of the present invention is performed by fully charging the non-aqueous electrolyte battery with the voltage and current characteristics shown in FIG.
The presence or absence of a battery is electrically detected. In FIG. 1, the non-aqueous electrolyte battery is charged and the presence or absence thereof is detected in the following steps. In order to fully charge the non-aqueous electrolyte battery in the shortest time possible, first perform constant current charging. When the voltage of the non-aqueous electrolyte battery reaches the set value, constant current charging is switched to constant voltage charging. In this step, the charging current gradually decreases as the battery approaches full charge. When the non-aqueous electrolyte battery is fully charged, the charging current becomes almost zero. When the battery is fully charged, the battery is repeatedly charged and stopped at regular intervals. Set the voltage for charging the battery to the same voltage as for constant voltage charging. This is to prevent overcharge of the fully charged non-aqueous electrolyte battery. Detects battery voltage when charging is stopped. When the battery is set, the battery voltage is detected and it can be seen that there is a battery. When the battery is removed from the charger, the battery voltage becomes 0 when charging is stopped, and it is determined that there is no battery.

As described above, the method of detecting the presence / absence of the non-aqueous electrolyte battery of the present invention detects the battery voltage by detecting the presence / absence of the non-aqueous electrolyte battery in which the charging current becomes almost 0 after being fully charged. Can be determined. Therefore, the method of the present invention can detect the presence or absence of the non-aqueous electrolyte battery by electrically detecting the battery voltage without mechanically detecting the presence or absence of the battery as in the conventional case.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. However, the examples described below exemplify a method of detecting the presence or absence of a non-aqueous electrolyte battery for embodying the technical idea of the present invention, and the method of the present invention is an electric circuit of a charger. The set voltage, timing, etc. are not specified in the following states. The presence / absence detection method of the non-aqueous electrolyte battery of the present invention can be modified in various ways within the scope of the claims.

The charging circuit used in the method of the present invention is shown in FIG. The charging circuit shown in this figure is a charging power source 1
And a charge control means 2 for controlling the output of the power supply 1 to control the charge state of the battery, and a charge capacity display means 15.

The power supply 1 includes an input filter 3 for removing noise contained in a commercial power supply of 100 VAC, a rectifier circuit 4 for converting the input alternating current into direct current, and a switching for converting the direct current of the rectifier circuit 4 into high frequency alternating current. Section 5, conversion transformer 6 for converting alternating current into a predetermined voltage, and conversion transformer 6
A rectifying / smoothing circuit 7 for rectifying the AC output of the above to convert it into a smooth DC, a PWM control circuit 8 for controlling the switching unit 5 to control the DC output, and a signal from the charging control means 2.
A photo coupler 9 that electrically insulates and inputs the PWM control circuit 8 is provided.

The charging control means 2 comprises an output adjusting circuit 10 for adjusting the output of the power source 1 to control the charging current of the battery, a charging control switch SW, a computing means 11 and a voltage / current detection circuit 12.

The output adjusting circuit 10 includes a constant voltage charging circuit 13
And a constant current charging circuit 14. Constant voltage charging circuit 1
3 and the constant current charging circuit 14 include operation amplifiers 13A and 14A.

Operation amplifier 13A of constant voltage charging circuit 13
Connects the + side input terminal to the battery via a voltage dividing resistor. The-side input terminal is connected to the reference power source EV. The outputs of the operational amplifiers 13A and 14A are connected to the photocoupler 9 via diodes.

This constant voltage charging circuit 13 includes an operational amplifier 1
The voltage of the + side input terminal of 3A, that is, the divided voltage of the battery is compared with the reference voltage EV connected to the − side, and the output of the operation amplifier 13A is inverted to + −. When the battery voltage becomes higher than the set voltage, the + side voltage becomes higher than the − side reference voltage. Then, the output of the operational amplifier 13A becomes +, the current does not flow through the diode, and the light emitting diode of the photocoupler 9 stops emitting light. In this state, the PWM control circuit 8 controls the switching element of the switching unit 5 to reduce the output. The reference voltage EV of the constant voltage charging circuit 13 determines the reference voltage for charging the battery with a constant voltage.

The constant current charging circuit 14 is an operational amplifier 14A.
The + side input terminal is connected to the current detection resistor RS, and the-side input terminal is connected to the reference power source ES. This circuit operates when the charging current of the battery becomes larger than the set value.
The voltage of the + side input terminal of 4A becomes higher than the-side reference voltage ES. In this state, the operational amplifier 14A sets the output voltage to +, and the diode is reverse biased so that the light emitting diode of the photocoupler 9 does not emit light. In this state, PWM
The control circuit 8 controls the switching element of the switching unit 5 to control the output to be low, thereby reducing the charging current of the battery. Therefore, the constant current charging circuit 14 prevents the charging current of the battery from becoming larger than the set value and performs the constant current charging. The reference voltage ES of the constant current charging circuit 14 determines the charging current for the main charging of the battery and for the pulse charging.

The charge control switch SW is connected between the power source 1 and the battery and is turned off when the charging current of the battery is stopped and turned on when the battery is charged.

A microcomputer can be used as the calculating means 11.
The calculation means 11 calculates the output of the voltage / current detection circuit 12 to control the charge control switch SW, and also calculates the input signal of the voltage / current detection circuit 12 to detect the presence or absence of a battery,
The presence or absence of the battery is output to the display means 15. The display means 15 displays the presence / absence of a battery.

Further, the calculating means 11 has a timer (not shown) built therein, and switches the charge control switch SW at a constant cycle after detecting the full charge of the non-aqueous electrolyte battery. The calculation means 11 turns on the charge control switch SW when charging the fully charged non-aqueous electrolyte battery, and switches it off when charging is suspended.

The voltage / current detection circuit 12 includes a current detection resistor R
An operational amplifier 12A that amplifies the voltage drop of S, an A / D converter 12B that converts the output signal of the operational amplifier 12A into a digital quantity, and an A that converts the voltage of the battery into a digital quantity.
And / D converter 12C.

The charging circuit shown in FIG. 2 charges a non-aqueous electrolyte battery such as a lithium ion secondary battery according to the flow chart shown in FIG. 3 and determines the presence or absence of the battery. [N1] Start charging. [N2] The calculation unit 11 processes the signal from the voltage / current detection circuit 12 to determine whether or not current is flowing in the battery. [N3] If there is no current in the battery, "No battery"
To determine. The first time when charging starts, no current flows in the battery when there is no battery. This is because if there is a battery, a charging current will flow at the beginning of charging. [N4] The display means displays "no battery". [N5] When it is determined that the battery is flowing in the battery, the calculation means 11 processes the input signal from the voltage / current detection circuit 12 and determines whether or not the battery is fully charged. When the non-aqueous electrolyte battery is fully charged, the battery voltage rises to a predetermined value and the charging current hardly flows. Therefore, it can be determined from the voltage and current of the battery whether the battery is fully charged. If the battery is not fully charged, loop to [N2] to continue charging the battery. [N6] When the non-aqueous electrolyte battery is fully charged, the display means displays "full charge". It is preferable that the display means can display the full charge in addition to the display of the presence or absence of the battery. [N7] When the battery is fully charged, charging is stopped. That is, the charge control switch SW is turned off to disconnect the battery from the power supply 1. [N8] Disconnect the battery from the power supply 1 and detect the battery voltage. If there is no battery voltage, that is, 0V, it is determined that there is no battery, and the process proceeds to [N3]. [N9] When the battery voltage is detected, the timer of the calculation means 11 determines whether or not x minutes have elapsed since the charging was stopped. It loops to the step [N8] until x minutes have passed. [N10] When x minutes have passed, charging is restarted. [N11] It is determined whether or not y seconds have elapsed since resumption of charging. Charging is continued until y seconds have passed. When y seconds have elapsed after resuming charging, the process loops to the step [N7], and then the steps [N7] to [N11] are repeated to detect the presence / absence of the non-aqueous electrolyte battery at a constant cycle. Fig. 1 shows the process of charging the non-aqueous electrolyte battery.
As shown in (1), constant current charging is first performed, and then the battery is switched to constant voltage charging when the battery approaches full charge.

As shown in FIG. 1, the method for detecting the presence / absence of a non-aqueous electrolyte battery that has been fully charged in such a process is as follows. Is designed to be equal to the voltage for constant voltage charging, or designed to be approximately equal to this voltage, or designed to be slightly lower than this voltage,
It has the feature that the presence or absence can be detected without overcharging the non-aqueous electrolyte battery.

[0024]

The method for detecting the presence / absence of a battery in a non-aqueous electrolyte battery charger according to the present invention is a method of detecting a battery voltage when charging is stopped by repeating charging and stopping after the battery is fully charged. The presence or absence of is determined. For this reason, unlike the conventional method, it is possible to determine the presence or absence of a purely electrically fully charged non-aqueous electrolyte battery without using a member that determines the presence or absence of the battery in a mechanically movable part such as a push button switch. it can. Therefore, the method of the present invention does not require the use of a part such as a push button switch, has a feature that it can be mass-produced at low cost by omitting the part cost and the step of assembling this part at a predetermined position of the casing. is there.

Further, the method for detecting the presence / absence of the non-aqueous electrolyte battery of the present invention does not detect the presence / absence of the non-aqueous electrolyte battery mechanically, but electrically detects the presence / absence of the battery.
Malfunctions due to the deterioration of the detection parts over time can be reduced to a minimum, it operates accurately over a long period of time, and the presence or absence of a battery can be determined with high reliability.

[Brief description of drawings]

FIG. 1 is a graph showing the voltage and current characteristics of a battery when a non-aqueous electrolyte battery is charged by the method of one embodiment of the present invention to detect the presence or absence of the battery.

FIG. 2 is a block diagram of a charging circuit that determines the presence / absence of a non-aqueous electrolyte battery by charging the non-aqueous electrolyte battery with the voltage / current characteristics shown in FIG.

FIG. 3 is a flowchart for charging a non-aqueous electrolyte battery using the charging circuit shown in FIG. 2 and then detecting the presence or absence of the battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Power supply 2 ... Charge control means 3 ... Input filter 4 ... Rectifier circuit 5 ... Switching part 6 ... Conversion transformer 7 ... Rectification smoothing circuit 8 ... PWM control circuit 9 ... Photo coupler 10 ... Output adjusting circuit 11 ... Arithmetic means 12 ... Voltage Current detection circuit 13 ... Constant voltage charging circuit 13A ... Operational amplifier 14 ... Constant current charging circuit 14A ... Operational amplifier 15 ... Display means SW ... Charge control switch RS ... Current detection resistance

Claims (1)

[Claims] 1. A method of detecting the presence or absence of a battery after the battery is fully charged by constant voltage charging in the final process of fully charging the battery, and after the battery is fully charged, charging of the battery is performed at predetermined time intervals. A method for detecting the presence / absence of a battery in a non-aqueous electrolyte battery charger, characterized in that the presence / absence of a battery is detected by repeating a pause and detecting the battery voltage during the pause.