Lithium battery maintenance circuit knowledge -Lithium - Ion Battery Equipment

Lithium battery maintenance circuit knowledge -Lithium - Ion Battery Equipment

Li-ion battery maintenance circuit:

The charge and discharge maintenance circuit of two lithium-ion batteries consists of two FETs and a special maintenance integrated block S8232. The overcharge control tube FET2 and the overdischarge control tube FET1 are connected in series, and the battery voltage is monitored by the maintenance IC. When the battery voltage rises to 4.2v, the overcharge maintenance tube FET1 stops charging. In order to prevent misoperation, a delay capacitor is usually added to the external circuit. When the battery is in discharge state and the battery voltage drops to 2.55v, the over-discharge control tube FET1 fails and the load power supply stops. Over-current maintenance refers to the operation in which FET1 cuts off and stops discharging to the load when there is a large current flow on the load in order to maintain the battery and the FET. Overcurrent detection is to use the on-resistance of the FET as a detection resistor to monitor its voltage drop, and stop discharging when the voltage drop exceeds the set value. A delay circuit is also generally added to the circuit to distinguish between inrush current and short-circuit current. The circuit has perfect functions and reliable performance, but it is highly professional, and the dedicated chip is not easy to buy and not easy for laymen to copy.(Lithium - Ion Battery Equipment)

Simple charging circuit:

There are many businesses that sell lithium-ion batteries without a charging pad. Its superior performance and low price can be used for repair and replacement of self-made products and lithium-ion batteries, so it is loved by the majority of electronics enthusiasts. Interested readers can refer to Figure 2 to make a charging pad. The idea is to charge the battery at a constant voltage to make sure it doesn't overcharge. The input DC voltage is 3 volts higher than the rechargeable battery voltage. R1, Q1, W1, TL431 constitute a fine adjustable voltage regulator circuit, Q2, W2, R2 constitute an adjustable constant current circuit, Q3, R3, R4, R5, LED as a charging indicator circuit. As the rechargeable battery voltage increases, the charging current gradually decreases. When the battery is fully charged, the voltage on R4 drops, causing Q3 to stop and the LED to drop. To keep the battery fully charged, please continue charging for 1-2 hours after the indicator light goes out. Please install the radiator suitable for Q2 and Q3 when using. The advantages of this circuit are: simple fabrication, easy purchase of components, safe charging, intuitive display, and no damage to the battery. After replacing W1, multiple lithium-ion batteries can be charged in series, and replacing W2 can adjust a wide range of charging current. The disadvantage is: there is no over-discharge control circuit.



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