Design ideas for lithium battery protection circuit and charging scheme

qwqwqw2088

Design ideas for lithium battery protection circuit and charging scheme [Copy link]

1. Circuit parameters

1. Charging power source: If it is a USB power source, the rated voltage is 5V.

2. Determine the capacity and voltage parameters of the battery to be used. If you use 18650, you can choose a lithium battery of 3.7V with a capacity of 2600mAh.

3. Load parameters

2. Circuit board functional requirements

1. Charging voltage protection, to prevent accidents caused by choosing the wrong charger (too high input voltage).
2. Overcharge protection, to prevent accidents caused by charging for too long.
3. Overload protection, power off when the motor is blocked (high current).
4. Over-discharge protection
5. Boost module. (Boost voltage based on battery voltage)

3. Indicator Light

1. Charging indicator light\Full indicator light
2. Working indicator light
3. Low battery voltage indicator light
4. Overload indicator light

4. Functional Description

1. Turn off the switch and all lights will go out.

2. If an abnormality occurs during load operation, the overload protection is activated and the load circuit is automatically disconnected (controlled by components and automatically restored later).

3. When charging, the red light is on, fully charged, and the green light is on

Notes
The protection board generally consumes uA level current. If the battery voltage is lower than 2.8V, the protection IC will enter sleep mode and the power consumption will be lower. If the lithium battery is not used for a long time, in addition to the protection board's self-consumption, the lithium electrons will also self-discharge, which will also cause the power to drop. It is generally recommended to charge once every 3 months. The standard is to charge a single lithium battery to about 3.8V. Why 3.8V? Because 3.8V is the most suitable voltage for long-term storage of lithium batteries. `

If the voltage is too low and the battery cannot be charged, you can bypass the protection board and charge the lithium battery directly. When the voltage reaches above the turn-on voltage, you can use the protection board to charge it directly.