A method for controlling a universal rechargeable battery constituted by employing lithium-ion battery, wherein the universal rechargeable battery comprises therein a lithium-ion battery charging/discharging control circuit comprising a lithium-ion battery charging control circuit, a lithium-ion battery detection circuit and a DC-DC step-down regulator discharging circuit;
- the method for controlling the universal rechargeable battery includes the following control conditions:
- control condition 1, after a charging power source is connected to the universal rechargeable battery, the lithium-ion battery charging/discharging control circuit performs a charging status upon detection of the charging voltage connection, and during the charging status, the lithium-ion battery charging/discharging control circuit cutoffs the regulated discharge voltage output and performs charging of the lithium-ion battery;
- control condition 2, during the charging status, the lithium-ion battery charging/discharging control circuit detects an output voltage of the lithium-ion battery and selects a charging scheme of trickling charge, constant-current charge or constant-voltage charge to charge the lithium-ion battery according to the output voltage of the lithium-ion battery, and during the charging status, the lithium-ion battery charging control circuit detects a maximum threshold output current of the charging power source, and charges the lithium-ion battery at the maximum threshold output current of the charging power source when the maximum threshold output current of the charging power source is smaller than a preset charging current value, and cutoffs the charging of the lithium-ion battery when a charging current during the constant-voltage charge is decreased to a preset fully charged determination current;
- control condition 3, when the charging power source is disconnected from the universal rechargeable battery, the lithium-ion battery charging/discharging control circuit detects the disconnection of the charging power source, and discharges remaining power stored in a filter capacitor during the charging, such that a voltage across a positive electrode and a negative electrode of the universal rechargeable battery drops rapidly to be equal to or lower than a maximum open circuit voltage and a discharging status is performed, and during the discharging status, the lithium-ion battery charging/discharging control circuit cutoffs a charging and performs a regulated voltage discharge, and performs a regulated voltage output according to control condition 4, wherein the maximum open circuit voltage ranges from 1.5V to 1.725V;
- control condition 4, during the discharging status, the lithium-ion battery charging/discharging control circuit detects the output voltage of the lithium-ion battery, and performs a regulated voltage output by:
- decreasing the output voltage of the lithium-ion battery to a first output voltage when the output voltage of the lithium-ion battery is greater than a low power voltage VL;
- decreasing the output voltage of the lithium-ion battery to a second output voltage when the output voltage of the lithium-ion battery is greater than a discharge cutoff voltage VD while equal to or lower than the low power voltage VL, and restoring the output of the lithium-ion battery to the first voltage when the output voltage of the charged lithium-ion battery is greater than VL+ΔVL, wherein VL is a preset low power voltage of the lithium-ion battery, ΔVL is a preset backlash voltage of the lower power voltage detection threshold of the lithium-ion battery, and VD is a preset discharge cutoff voltage of the lithium-ion battery, wherein the first output voltage ranges from 1.35V to 1.725V, and the second output voltage ranges from 0.9V to 1.35V;
- control condition 5, during the discharging status, the lithium-ion battery charging/discharging control circuit detects the output voltage of the lithium-ion battery, and cutoffs the regulated voltage output when the output voltage of the lithium-ion battery drops to be equal to or lower than the discharge cutoff voltage VD and restores the regulated voltage output according to control condition 4 when the output voltage of the charged lithium-ion battery is greater than VD+ΔV2, wherein ΔV2 is a preset backlash voltage of the discharge cutoff voltage detection threshold of the lithium-ion battery;
- control condition 6, during the charging of the universal rechargeable battery, the lithium-ion battery charging/discharging control circuit detects a temperature of the lithium-ion battery, and cutoffs the charging of the lithium-ion battery when the temperature of the lithium-ion battery raises to a charging upper threshold temperature TCH and restores the charging of the lithium-ion battery when the temperature of the lithium-ion battery decreases to be lower than TCH−ΔTL, wherein TCH is a preset charging upper threshold temperature of the lithium-ion battery and ΔT1 is a preset backlash temperature corresponding to a backlash voltage of the TCH detection threshold;
- control condition 7, during the discharging of the universal rechargeable battery, the lithium-ion battery charging/discharging control circuit detects the temperature of the lithium-ion battery, and cutoffs the regulated voltage output when the temperature of the lithium-ion battery raises to a discharging upper threshold temperature TDH and restores the regulated voltage output when the temperature of the lithium-ion battery decreases to be lower than TDH−ΔT2, wherein TDH is a preset discharging upper threshold temperature of the lithium-ion battery, and ΔT2 is a preset backlash temperature corresponding to a backlash voltage of the TDH detection threshold;
- the lithium-ion battery is charged according to control condition 2 when control condition 1 determines that the charging power source is connected to the universal rechargeable battery and control condition 6 allows for the charging of the lithium-ion battery, and the charging of the lithium-ion battery is cutoff when control condition 6 prohibits the charging of the lithium-ion battery;
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- output power of the lithium-ion battery is stepped-down and regulated output according to control condition 4 when control condition 3 determines that the universal rechargeable battery is disconnected from the charging power source and both control condition 5 and control condition 7 allow for the discharging output of the lithium-ion battery, and the lithium-ion battery charging/discharging control circuit cutoffs the regulated voltage output when either one of control condition 5 and control condition 7 prohibits the discharging output of the lithium-ion battery.