JPH01268432A - Battery charger - Google Patents

Abstract

PURPOSE:To perform charge operation reliably by determining charge time based on a battery charge starting voltage obtained through connection with a predetermined load and a battery characteristic stored in a charge control circuit. CONSTITUTION:When a battery B is connected to a battery charger A, a discharge timer circuit 8A detects the voltage between terminals 10A, 10B and starts operation and when the timer circuit 8A expires, terminal voltage is read into a charge control circuit 5 through an A/D converter 3. The charge control circuit 5 storing a battery charge characteristic determines charge current and charge time such that the charge rate will be higher than 90% based on such information as quick charge rate, intermediate charge rate, normal charge rate and battery temperature set in a charge setter 4, then the determined charge current and charge time are fed to a charge current determining circuit 6 in order to start charge operation. When the charge time set through the charge control circuit 5 expires, a charge switch circuit 7 is turned OFF and auxiliary charge operation is carried out through an auxiliary charge resistor 7A.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a battery charging device that sets charging time according to the degree of battery consumption.

(Prior Art) Conventionally, this type of battery charging device monitors the battery terminal voltage during charging, and terminates charging when this voltage reaches a preset voltage.

However, the conventional method of charging the battery by detecting the battery voltage can only charge 70 to 80% of the battery's original capacity (see Figure 2A).
). The charging characteristics of a nickel-cadmium battery are shown in FIG. 3, and the terminal voltage due to charging temporarily increases depending on the charging rate.

When this point reaches 70~b, the voltage begins to drop. A general characteristic is that the voltage is about 90% when the voltage is 1 ΔV (for example, -5%) from the highest voltage.

Therefore, it has been found that the method of stopping charging only by monitoring the terminal voltage has problems in terms of characteristics.

An object of the present invention is to provide an excellent battery charging device that can solve the above problems.

(Means for Solving the Problems) In order to achieve the above object, the present invention has the following functions.

The present invention measures the terminal voltage when a load that flows a current suitable for the battery capacity used is connected for a certain period of time, determines which point in the battery discharge characteristics the battery is at in a charging control circuit, and charges the battery based on this. It determines the time. That is, a voltage conversion power supply circuit that converts an AC voltage to a DC voltage, a connection terminal that connects a battery to be charged, a connection terminal that connects the battery to a predetermined load for a certain period of time, and a connection terminal that connects the battery to be charged. a discharge timer circuit comprising means for obtaining the subsequent voltage characteristics and means for disconnecting the load and connecting the charging circuit; and an A/D converter for A/D converting the voltage characteristics given from the discharge timer circuit. , voltage information of the A/D converter.

A charging control circuit calculates the charging time based on the information of the charging time setter and the stored charge/discharge characteristics and provides an ON/OFF signal to the switch of the charging circuit, and the voltage conversion is performed based on the information of the charging control circuit. It is characterized by being comprised of a switch circuit that connects a power supply circuit and a connection terminal that connects to a battery.

(Function) Therefore, according to the present invention, the charging time is determined and executed according to the charging start voltage of the battery obtained by connecting it to a predetermined load and the battery characteristics stored in the charging control circuit. Therefore, charging can be performed reliably.

(Example) FIG. 1 shows the configuration of an embodiment of the present invention.

In FIG. 1, A indicates the charger of the present invention, and B indicates the battery to be charged.This also applies to a single battery.

It does not matter whether it is set in an electronic device or not.

In charger A, 1 is an AC 100V commercial power outlet, 2 is a voltage conversion power supply circuit that converts the AC 100V to a DC voltage suitable for battery charging, and 3 is an A/D converter for the battery voltage of a battery connected to a predetermined load. A/D converter,
4 is a charging time setter for setting the charging time, for example, 1 to IO time, and 5 is a charging control for setting the charging current and charging time based on information from the A/D converter 3 and the charging time setter 4. A circuit that stores the charging and discharging characteristics of the battery. 6 is a charging current determination circuit that drives the charging switch circuit, 7 is a charging switch circuit, 7A is a resistor for auxiliary charging, 8 is a battery voltage detection section, 8A is a discharge timer circuit, 8B is a charging relay, and 8C is a relay unit. terminals, 9 is a predetermined load resistance for battery discharge, 10 is a connection terminal, 10A is a (+) terminal, 10B is a (-) terminal, 10C is a thermistor output terminal,
A thermistor 11 detects the temperature of the battery case, and the charging control circuit 5 controls the charging time of the battery according to the temperature of the battery case.

Next, the operation of the above embodiment will be explained.

Battery B, which is a single battery to be charged or is built into an electronic device
Connect to battery charger A. The discharge timer circuit 8A is activated by detecting the voltage applied to the battery connection terminal 10A and IOB. The above clock time is set to an arbitrary time of 10 to 60 seconds. When this times out,
The terminal voltage of the battery B is sent to the A/D converter 3. A/D
Converter 3 provides an A/D conversion output to charging control circuit 5 .

The charging control circuit 5 stores the battery charging and discharging characteristics, and stores the rapid charging rate (LH) from the charging time setting device 4.

The charging current determination circuit 6 sets the charging current and charging time so that the charging rate is 90% or more based on the setting information such as medium-speed charging rate (3H), normal charging rate (IOH), and battery temperature.
At the same time, the discharge timer circuit 8A turns on the charging relay 8B and starts supplying current to the battery B being charged. Next, charging control circuit 5
When the charging time set in is over, the charging switch circuit 7 is turned OFF to stop charging, and
Supplementary charging is performed by the auxiliary charging resistor 7A.

(Effects of the Invention) As is clear from the above examples, the present invention has the following effects.

When the battery to be charged is connected to the terminal of the charging device.

Power is supplied to a predetermined load for a predetermined period of time, the current operating voltage of the battery is determined, and this voltage is used to determine the charging time by referring to the battery's original charging/discharging characteristics and charging conditions (time). Because it is a device to set and charge,
100 compared to those that rely only on the terminal voltage during charging.
Can charge close to %.

Moreover, it has the characteristic of not causing overcharging.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram of a battery charger according to an embodiment of the present invention, and Fig. 2 is a secondary nickel charger using a conventional charger.
Charging characteristic diagram of cadmium battery, Figure 3 shows secondary nickel battery.
It is a charge-discharge characteristic diagram of a cadmium battery. 3... Voltage A/D converter, 4... ITlf during charging
l setting device, 5...Charging control circuit, 6...Charging current determining circuit, 7...Charging switch circuit, 7A...
Auxiliary charging resistor, 8...discharge timer circuit, 9...
・Load resistance, A...Charger, B...Battery to be charged. Patent applicant Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] A voltage conversion power supply circuit that converts AC voltage to DC voltage, a connection terminal that connects the battery to be charged, and a connection terminal that connects the battery to a predetermined load for a certain period of time. a discharge timer circuit comprising means for obtaining voltage characteristics and means for disconnecting the load and connecting the charging circuit; an A/D converter for A/D converting the voltage characteristics given from the discharge timer circuit; A/D converter voltage information,
A charging control circuit calculates the charging time based on the information of the charging time setter and the stored charge/discharge characteristics and provides an ON/OFF signal to the switch of the charging circuit, and the voltage conversion is performed based on the information of the charging control circuit. A battery charging device comprising a switch circuit that connects a power supply circuit and a connection terminal that connects to a battery.