JPS63114078A - Charging method for lead acid battery - Google Patents

Abstract

PURPOSE:To make it possible to charge a battery left after overdischarge by passing current in a direction opposite to the usual charge until the voltage of a battery becomes negative, then performing the usual charge. CONSTITUTION:When an a.c. power source 1 is turned on, the output of a transformer-rectifier assembly 2 is sent to a lead-acid battery 11 through a current controller 3, a diode 9, and a relay 10. A controller 6 is operated by the input from the first voltage detector 7 and the second voltage detector 8, and connected to a timer 5, and also connected to the current controller 3 to which a resistance 4 is connected in parallel. When a battery is normally charged, the controller 6 detects the voltage in the final charging stage by the output of the first voltage detector 7, and controls the current controller 3 to perform trickle charge. The second voltage detector 8 which has detecting voltage higher than the first voltage detector 7 operates when a battery left after overdischarge is connected, and the controller 6 operates the timer 5, and the relay 10 is switched over to reversely pass the current for a specified time.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a charging method for lead-acid batteries.

BACKGROUND OF THE INVENTION Conventionally, lead-acid batteries have generally been charged by passing a charging current from the anode to the cathode of the battery.

Problems to be Solved by the Invention In the above charging method, when a lead-acid battery that has been left unattended after being over-discharged (hereinafter referred to as an "over-discharged battery") is charged, the internal resistance of the over-discharged battery is high. Therefore, the charging current is small and it is difficult to charge. This tendency is remarkable in cathode absorption type sealed lead-acid batteries with a small amount of electrolyte, and in particular, sealed lead-acid batteries use a method in which charging with a minute current (hereinafter referred to as ``trickle charging'') is started after detecting the end-of-charge voltage. Since many chargers are used, when an over-discharged battery is charged with this type of charger, the internal resistance of the over-discharged battery is high, so the charging voltage reaches the end-of-charge voltage immediately after charging starts, i.e. There was a major problem in that the battery entered trickle charge, resulting in almost no charge.

Means for Solving the Problems The present invention solves the above problems, and after the start of charging,
This is characterized in that a current in the opposite direction to normal charging is passed for a predetermined period of time until the battery voltage becomes negative, and then normal charging begins.

Function: The present invention has the above-mentioned characteristics, so that it is possible to charge a battery that has been left over-discharged. This is thought to be because the internal resistance is reduced by passing a current in the opposite direction to the normal direction through the overdischarged battery.

Also, when charging an overdischarged MN battery with a conventional charger that enters trickle charging after detecting the end-of-charge voltage,
As described above, the battery enters trickle charging immediately after charging, but since the internal resistance of the overdischarged battery is high, the charging voltage during trickle charging is higher than the normal trickle charging voltage. Therefore, if this voltage is detected and a current is passed in the opposite direction to normal charging for a predetermined period of time until the battery voltage becomes negative, normal charging is started, both over-discharged batteries and normally discharged batteries. Can be charged.

Example An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration diagram of a charger according to the present invention, which normally performs charging with a quasi-constant current and enters trickle charging after detecting the voltage at the end of charging.

This charger starts normal charging after flowing a current in the reverse direction for a predetermined period of time when an MN over-discharged battery is connected. That is, the output of the transformer rectifier 2 which receives the AC power source 1 as input is connected to the lead-acid battery 11 through the current controller 3, the backflow prevention diode 9, and the relay contact IO. Further, the control section 6 receives the first voltage detection section 7 and the second voltage detection section 8 as inputs, and outputs the current control section 3 connected to the timer 5 and connected to the resistor 4 in parallel.

During normal charging, the control unit 6 calculates the voltage at the end of charging from the output of the first voltage detection unit 7, and operates when ffl+battery is connected.The control unit 6 operates the timer 5 and switches the relay contact 10. An operation is performed in which current is passed in the opposite direction for a predetermined period of time.

According to the present invention, a sealed lead-acid battery (4V, 4V) after being left overdischarged
Fig. 2 shows the charging characteristics when a battery (Ah, internal resistance 682Ω) is connected. In this example, the reverse charging time is 60 minutes, the set voltage of the first voltage detecting section 7 is 4.9 V, and the set voltage of the second voltage detecting section is 6.0 V. This is the charging characteristic when set to OV. After charging begins, the internal resistance of the sealed lead-acid battery is high, so a relay is activated and reverse charging is performed for 60 minutes before normal charging begins, allowing sufficient charging for recovery.

Effects of the Invention As described above, the charging method of the present invention can charge over-discharged batteries, which has been difficult to charge up until now, or can be done by simply applying a reverse charging current for a predetermined period of time without using any special means. , the effect is enormous.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a charging characteristic curve diagram when charging according to the charging method of the present invention. 1 is an AC power supply, 2 is a transformer rectifier, 3 is a current control unit, 4 is a resistor, 5 is a timer, 6 is a control unit, 7 is a first voltage detection unit,
8 is a second voltage detection section, 9 is a backflow prevention diode, 10
is a relay contact, 11 is a lead-acid battery

Claims (1)

[Scope of Claims] 1. A method for charging a lead-acid battery, which is characterized in that after charging starts, a current in the opposite direction to normal charging is passed for a predetermined period of time until the battery voltage becomes negative, and then normal charging begins. 2. The lead-acid battery according to claim 1, wherein after the start of charging, when the charging voltage reaches a predetermined voltage higher than the normal charging voltage, a current flows in the opposite direction to normal charging. Charging method.