Power tool lithium battery low voltage protection

To safely operate such a battery, the discharge current rate and battery voltage level must be monitored. Undervoltage protection is crucial when using lithium-ion batteries because if the battery is discharged below its rated value, the battery will become damaged and potentially pose a safety hazard.

Lithium battery applications are ubiquitous, but they require good management to ensure safe and reliable use, especially to prevent the voltage from dropping below the safety line, which we call over-discharge. This requires all batteries to have a safety protection function, which is low voltage cut-off protection, abbreviated as LVC.

This requires all batteries to have a safety protection function, which is low voltage cut-off protection, abbreviated as LVC. It is like a smart safety switch. Its function is to automatically detect when the battery voltage is about to drop to a dangerous level and cut off the power supply from the battery to the device in time.

Low voltage cutoff is a key safety feature, but it is not a universal voltage value that applies to all lithium batteries. Different batteries have their own unique chemical systems and therefore have different discharge cutoff voltages.

Different batteries have their own unique chemical systems and therefore have different discharge cutoff voltages. The discharge cut-off voltage of a single-cell lipo battery is generally 2.5 ~ 3V, the safe cut-off voltage of a lifepo4 battery is 2.5V, and the minimum discharge cut-off voltage of a 18650 battery is 3V.

Combining undervoltage protection and overcurrent protection will ensure safe operation of the 48-V battery. For this design, a 48-V, 20-Ah lithium-ion battery was selected. Monitoring a 48-V lithium ion battery can be achieved using the TLV9022 device in combination with the TL431 shunt reference.