JP2525653B2 - Charger - Google Patents

Description

The present invention relates to a charging device for charging a battery.

[Conventional technology]

Conventionally, there is a charging device having a function of discharging electric energy remaining in the battery before starting charging the battery and then starting charging. That is,
If the battery is charged with electric energy remaining, the so-called memory effect of the battery causes deterioration of the battery. Therefore, the charging is started after the discharging process is performed once.

FIG. 2 shows a conventional example. In the figure, reference numeral 1 denotes a battery mounting detecting means, which turns on the main switch SW1 when detecting that the battery 2 is mounted on the charging device, thereby connecting the terminal of the battery 2 to the charging circuit side. 3 is a charging circuit, which is wired so as to be connected to the battery 2 via a first control switch SW2 connected in series to the output side contact of the main switch SW1. Reference numeral 4 denotes a discharge circuit, which is wired so as to be connected to the battery 2 via a second control switch SW3 connected in series to the output side contact of the main switch SW1. Reference numeral 5 denotes a battery terminal voltage detection circuit, which is wired so as to be connected to the terminal of the battery 2 via the main switch SW1.
Reference numeral 6 is a charge / discharge switching circuit that controls the on / off operation of the first and second control switches SW2 and SW3. The switching operation is performed according to the output terminal voltage of the battery 2 detected by the battery terminal voltage detection circuit 5. . Reference numeral 7 denotes display means for displaying the operation mode of the charging device, and the display is switched according to the signal output from the charge / discharge switching circuit 6.

Next, the operation of such a conventional example will be described. When the battery is not charged, the main switch SW1 and the first and second control switches SW2 and SW3 are off, and when the battery 2 is mounted on the charging contact, the battery mounting detection means 1 is the main switch SW1. Is turned on and the second control switch SW3 is turned on, and the battery terminal voltage detection circuit 5 starts detecting the terminal voltage of the battery 2. The battery terminal voltage detection circuit 5 detects the output voltage of the battery 2 when the discharge circuit 4 is connected to the battery 2 as a load, and the output voltage drops to about 4.4 V (when nickel-cadmium battery is used as the battery). Until
The charge / discharge switching circuit 6 is instructed to continue the discharge operation by the discharge circuit 4. This 4.4 volt is battery 2
Is a threshold level for determining that the battery has been fully discharged under the load condition.

When the terminal voltage of the battery 2 drops to about 4.4 V, the battery terminal voltage detection circuit 5 instructs the charge / discharge switching circuit 6 to turn on the first control switch SW2 and turn off the second control switch SW3, and the battery 2 To start charging.

In this way, by once discharging and then starting charging, deterioration due to the memory effect of the battery is prevented.

[Problems to be Solved by the Invention]

However, in the charging device having such a function, in order to shorten the processing time until completion of charging,
The battery is forcibly discharged by the constant current source built into the discharge circuit. As a result, when a battery with a relatively large amount of residual power energy is discharged, even if the constant current source is forcibly attracted, the battery is not electrically burdened, but if the residual power energy is extremely low, the battery is Since it is in an over-discharged state, it causes damage or deterioration. Also, as is well known, a new battery that has not been used at all is not charged, so it must be charged before it is used.However, according to the conventional charging device, a new battery is used in the discharging process before the start of charging. Since the battery is always in the over-discharged state, there is a problem of promoting deterioration of the battery.

The present invention has been made in view of the above problems, and an object thereof is to provide a charging device that performs charging without causing damage or deterioration of the battery.

[Means for solving the problem]

In order to achieve this object, the present invention provides a charging device having a function of discharging and then charging according to electric power energy remaining in a battery, in a no-load state of the battery and a load state of performing the discharge. A detection means for detecting the voltage across each of the terminals is provided, and the voltage across the battery when there is no load due to the reduction of the residual power energy of the battery is
When the voltage is equal to or more than a predetermined value, the discharging is performed, when the voltage is less than the first predetermined value, the charging is performed without performing the discharging, and when the voltage across the load drops to the second predetermined value. [Characteristics] Charging is performed by stopping the discharge [Operation] In the charging device of the present invention having such a configuration, first, the output voltage of the battery in the no-load state is detected, and the detected voltage is When the voltage is lower than a first threshold voltage which is a preset first predetermined value, it is determined that the residual power energy of the battery is extremely low or the battery is new, and charging is performed without performing discharge processing, on the other hand,
When the threshold value is exceeded, discharge processing is performed assuming that a large amount of residual power energy exists, and discharge is stopped and charging is performed based on the second threshold voltage that is the second predetermined value, so the battery is deteriorated by the discharge processing. It is possible to solve such problems.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIG. First, the configuration will be described. In the figure, reference numeral 10 is a battery mounting detection means, which charges a terminal of the battery 11 by turning on a main switch SW11 that detects that the battery 11 is mounted in a charging device. Connect to the circuit side.
Reference numeral 12 denotes a charging circuit, which is wired so as to be connected to the battery 11 via the first control switch SW12 which is connected in series to the output side contact of the main switch SW11. Reference numeral 13 is a discharge circuit, which is wired so as to be connected to the battery 11 via a second control switch SW13 connected in series to the output side contact of the main switch SW11. A battery terminal voltage detection circuit 14 is wired so as to be connected to the terminal of the battery 11 via the main switch SW11. Reference numeral 15 is a no-load terminal voltage detection circuit, which detects the output voltage of the battery 11 when there is no load, via the main switch SW11. Reference numeral 16 is a charge / discharge switching circuit that controls the on / off operation of the first and second control switches SW12 and SW13, and the switching operation is the battery detected by the battery terminal voltage detection circuit 14 and the no-load terminal voltage detection circuit 15. Performed according to the output terminal voltage of 11. Reference numeral 17 is a display means for displaying the operation mode of the charging device, and the display is switched according to the signal output from the charge / discharge switching circuit 16.

Next, the operation of this embodiment will be described. When the battery 11 is not charged, the main switch SW11 and the first and second control switches SW12 and SW13 are off, and when the battery 11 is mounted on the charging contact, the battery mounting detection means 10 causes the main switch SW11 to operate. Turn on.

Next, the no-load terminal voltage detection circuit 15 generates the output terminal voltage of the battery 11 in the no-load state. Six nickel-cadmium batteries applied to this embodiment are connected in series to form 6
For a battery that produces a standard output of Volt, the no-load terminal voltage detection circuit 15 has a first threshold level for detecting whether the output voltage is less than 6.1 Volt in advance,
If the output voltage is less than 6.1 V, it is judged that the battery is a battery with a very small residual power energy or a new battery, and the second control switch SW13 is kept off and the first control switch SW12 is switched on. Instruct the charge / discharge switching circuit 16. That is, it is determined whether or not to discharge by utilizing the characteristic that the output voltage in the no-load state changes depending on the magnitude of the residual power energy of the battery. Therefore, charging of the battery 11 is started without performing discharge processing.

On the other hand, when the output voltage in the no-load state is 6.1 V or higher, the battery has a large amount of residual power energy, and the first control switch SW12 is kept off,
The charge / discharge switching circuit 16 is instructed to switch on the control switch SW13. Therefore, the battery 11 is discharged by the constant current source provided in the discharge circuit 13. The terminal voltage detection circuit 14 is the battery 11
The change in the output terminal voltage is detected, and when the output voltage drops to 4.4 V, the charge / discharge switching circuit 16 is instructed to turn off the second control switch SW13 and turn on the first control switch SW12. As a result, the discharging process is finished, and then the charging process of the battery 11 by the charging circuit 12 is started.
This 4.4 volt is a voltage which does not cause a so-called battery memory effect when sufficiently discharged, and is set in the terminal voltage detection circuit 14 in advance as a second threshold value which is a second predetermined value.

As described above, according to this embodiment, since the battery deteriorates due to damage if it is discharged before charging, the battery is started to be charged without being discharged. Therefore, it is possible to prevent the battery life from being shortened due to charging. it can.

Although the nickel-cadmium battery is used in this embodiment, the present invention can be applied to other types of batteries.

〔The invention's effect〕

As described above, according to the present invention, in the charging device having the function of discharging the electric energy remaining in the battery and then charging the battery, both ends of the battery in the unloaded state and the loaded state in which the discharging is performed. A detection means for detecting each voltage is provided, and both ends voltage detected at no load is compared with a first threshold voltage for discharging or charging, and at the same time, both ends voltage under load detected by the discharging is set to a second value. Since the configuration is such that the discharging is stopped and the charging is performed in comparison with the threshold voltage, the residual power energy of the battery is grasped in detail, and a problem such as deterioration of the battery due to the discharging process can be solved.

[Brief description of drawings]

 FIG. 1 is a block diagram of an embodiment of the present invention; FIG. 2 is a block diagram of a conventional example. In the figure: 10; battery mounting detection means 11; battery 12; charging circuit 13; discharge circuit 14; battery terminal voltage detection circuit 15; no-load terminal voltage detection circuit 16; charge / discharge switching circuit SW11; main switch SW12; First control switch SW13; Second control switch

Claims (1)

(57) [Claims] 1. A charging device having a function of discharging and then charging in accordance with electric power energy remaining in a battery, wherein a voltage between both ends of the battery in a no-load state and in a load state for discharging is detected. A detection means for
When the voltage across both ends of the battery under no load due to the reduction of the residual power energy is equal to or higher than a first predetermined value, the discharging is performed, and when the voltage is less than the first predetermined value, charging is performed without performing the discharging. The charging device is characterized in that the charging is performed by stopping the discharging when the voltage across both ends under load drops to a second predetermined value.