Lithium battery maintenance circuit knowledge

Lithium battery maintenance circuit: The charging and discharging maintenance circuit of two lithium batteries is shown in Figure 1. It consists of two field effect tubes and a dedicated maintenance integrated block S8232. The overcharge control tube FET2 and the overdischarge control tube FET1 are connected in series to the circuit. The maintenance IC monitors the battery voltage and controls it. In order to prevent malfunctions, a delay capacitor is usually added to the external circuit. When the battery is in a discharging state and the battery voltage drops to 2.55v, the over-discharge control tube FET1 is cut off and continues to supply power to the load. Over-current maintenance means that when the load has a large current flow cycle, the FET1 is controlled to turn off and continuously discharges to the load. The purpose is to maintain the battery and the field effect tube. The overcurrent detection uses the on-off resistance of the field effect tube as the detection resistance. When the voltage drop exceeds the set value, the voltage drop is monitored and the discharge continues. There is also a delay circuit to distinguish between surge current and short-circuit current. This circuit has perfect functions, reliable performance, but strong professionalism, and the special integrated block is not easy to buy, and it is not easy for laymen to copy. Simple charging circuit: Many companies now sell lithium batteries without a charging board. With its superior performance and low price, it can be used for maintenance and replacement of machineable products and lithium battery packs, so it is deeply loved by the majority of electronics enthusiasts. Readers with favorites can refer to Figure 2 to make a charging board. The principle is: Choose a stable voltage to charge the battery to ensure that it will not be overcharged. The input DC voltage is only 3 volts higher than the charged battery voltage. R1, Q1, W1, TL431 constitute a precision adjustable voltage regulating circuit, Q2, W2, R2 constitute an adjustable constant current circuit, and Q3, R3, R4, R5, and LED are used as a charging indicator circuit. As the battery voltage increases, the charging current gradually decreases. After the battery is fully charged, the voltage on R4 drops, causing Q3 to stop and the LED to drop. In order to ensure the satisfaction of the battery, please continue to charge for 1-2 hours after the indicator light is off. When using, please install the radiator on Q2 and Q3. The advantages of this circuit are: simple manufacture, easy to purchase components, safe charging, intuitive appearance, and will not damage the battery. After W1 is transformed, multiple lithium batteries can be charged in series, while W2 can be dispatched for a wide range of charging currents after transformation. The disadvantage is: no over-discharge control circuit. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: New energy vehicle battery silicon material or graphite material is better?