JPH079567Y2 - Lead acid battery charger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an improvement of a lead-acid battery charger.

2. Description of the Related Art Conventionally, as a problem of a lead storage battery charger, there is a charging method for a lead storage battery after being left over-discharged (hereinafter referred to as "over-discharge storage battery"). In particular, as a sealed lead-acid battery charger, a charger that uses a small current (hereinafter referred to as “trickle charge”) after detecting the end-of-charge voltage is used. In this case, since the internal resistance is high, the charging voltage reaches the end-of-charging voltage immediately after the start of charging, and there is a problem that the charging voltage shifts to trickle charging and is hardly charged.

Problems to be Solved by the Invention There are some problems in applying the above charging method for an over-discharged battery to an actual charger. The first is that only the over-discharged battery is detected and reverse charging is performed. In the case where the charger does not have this function and is configured to start reverse charging after the start of charging, reverse charging is also performed on the battery after normal discharging. Even a battery after normal discharge generally has a certain discharge capacity, and in this case, an excessive current may flow and destroy the charger. The second problem is the time for reverse charging. When the degree of over-discharging is low, the reverse charging time is short.When the degree of over-discharging is high, the reverse charging time is long, but when the degree of over-discharging is high, short reverse charging is performed. When the reverse charge is performed for a long time when the recoverability is poor and the degree of overdischarge is low, there is a problem that not only the recovery charge time becomes long but also the heat generation at the time of charging becomes large.

Table 1 shows that 4V, 4Ah sealed lead-acid battery (over-discharge left battery, internal resistance 600-800Ω) was used for reverse charging of 4.9V, 1.2A cut for 20-60 minutes, and then recovery charging ( 4.9V, 1.
The discharge duration is shown when 2V is cut and 16h). The discharge conditions are 1C (4A), F, V and 2.8V (20 ° C).

As shown in Table 1, there is a problem that the recovery rate is poor when the reverse charging time is short and the temperature rise is large when the reverse charging time is long.

The problem to be solved by the present invention is not only to recover a lead acid battery that has a high internal resistance and cannot be recovered by normal charging, but also to automatically detect it and recover it with an optimum reverse charging time. is there.

Means for Solving the Problems The present invention is to solve the above problems, and as a detection means for an over-discharged battery, a voltage detection unit for detecting an AC component of a charging voltage, and this value is a predetermined value or more. In this case, the control unit is provided with a control unit that causes a current in a direction opposite to the normal direction to flow until the AC component of the charging voltage becomes a predetermined value or less.

The present invention has the above-mentioned features, and in the case of over-discharge charging, once the battery is charged in the opposite direction to the normal charging, the internal resistance is reduced, the temperature rise of the battery is minimized, and the reverse charging is recovered. It is possible to improve the property.

This is a 4V, 4Ah sealed lead-acid battery (overdischarge left battery,
The internal resistance of 200 Ω) was used to measure the change in the AC component during reverse charging. As a result, as shown in Fig. 2, the internal resistance decreases during reverse charging. This is an application of the finding of the phenomenon that the components decrease.

Embodiment An embodiment of the present invention will be described.

FIG. 1 is a block diagram of a charger according to the present system, which is an over-discharging left-over battery, and in the case of charging a normal battery, a voltage detection unit 8
When the end-of-charge voltage is detected by, the control unit 6 controls the current control unit 5 to start trickle charging using the resistor 7. In the case of charging the over-discharged battery, the AC component included in the charging voltage is detected by the capacitor 13 and the resistor 14, rectified by the diode 12 and the capacitor 11, and input to the voltage detection unit 9 and the voltage detection unit 10. When the voltage is equal to or higher than a predetermined value, the voltage detection unit 9 operates, and the control unit 6 causes the contact of the relay to contact.
Switch 15 and perform reverse charging once. When the AC component becomes equal to or less than the predetermined value due to the reverse charging, the voltage detecting unit 10 operates, and the control unit 6 returns the contact 15 of the relay to return to the normal charging.

As described above, it is possible to perform the operation of detecting the AC component at the time of charging, starting the reverse charging, and returning to the normal charging when the AC component at the time of the reverse charging becomes equal to or less than the predetermined value.

As a result of testing using a 4V, 4Ah sealed lead-acid battery, when the AC voltage component when returning from reverse charging to normal charging is set to 0.2VP-P, it takes about 30 minutes for a battery with an internal resistance of 200Ω and an internal resistance of 1900Ω. With regard to the battery, it was possible to recover from the overcharged battery by going from reverse charge to normal charge in about 60 minutes. Further, the surface temperature of the battery was 42 ° C. or lower, and it was possible to suppress heat generation.

Effect of the Invention As described above, the present invention detects the AC component included in the charging voltage as the detection means of the over-discharged battery and once reverse charges and restores, the conditions for returning from the reverse charging to the normal charging are: The AC component at the time of reverse charging is detected. It is considered that the alternating-current component at the time of reverse charging indicates a change in internal resistance, so that the reverse charging time can be minimized and heat generation can also be minimized. Further, generally, there are few chargers that use a completely smoothed direct current as a charging current, and this method is very practical and extremely practical.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a characteristic curve diagram showing a change with time of an AC component contained in a charging voltage during reverse charging. 1 is an AC power supply, 2 is a transformer, 3 is a diode, 4 is a diode, 5 is a current controller, 6 is a controller, 7 is a resistor, 8 is a voltage detector, 9 is a voltage detector, 10 is a voltage detector. , 11 is a capacitor, 12 is a diode, 13 is a capacitor, 14 is a resistor, 15 is a relay contact, 16 is a diode, 17 is a lead acid battery

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Akio Komaki 2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo Shin-Kamido Electric Co., Ltd. Shinichi Yajima (56) Reference JP-A-55-109143 (JP , A) JP-A-55-111079 (JP, A) JP-A-48-33325 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A voltage detection unit for detecting an AC component of a charging voltage, and when this value is equal to or more than a predetermined value, once in a direction opposite to normal charging until the AC component of the charging voltage becomes equal to or less than a predetermined value. A lead-acid battery charger characterized by comprising a control unit for supplying an electric current.