Now, users have higher and higher requirements for batteries. Consumers aim to increase current hours and lengthen working hours. At the same time, the demand for small, light products is also strong. Batteries make up a considerable proportion of the volume and weight of any device, so manufacturers pay careful attention to reducing their size and weight.

These requirements have driven battery manufacturers to turn to battery chemistries such as Ni-MH and Li-ion for higher power density, lighter weight and faster charging. These features, especially fast charging, add to the complexity. The latest batteries require precisely controlled charging circuits not only to ensure they are fully charged, but also to maximize their life and prevent potentially dangerous overheating conditions.

Lithium-ion batteries usually use a constant current-constant voltage scheme, which still requires temperature monitoring to allow fast charging to start, and a mechanism to ensure that charging stops when the temperature exceeds a safe threshold, which requires the use of NTC thermistors.

NTC thermistors consume very little power, have excellent accuracy over a wide temperature range, and respond quickly to temperature changes.

During the lithium battery charging process, the protection function of the NTC thermistor is mainly reflected in the following aspects:

· Detect temperature changes during charging.

· Detects ambient temperature, allowing fast charging.

· Heating of the battery due to abnormal current was detected.

· Execute temperature compensation based on power display voltage measurement.

From this, it can be seen that when a lithium battery is being used, the battery's life and safety can be guaranteed. This is because the battery is protected through the NTC thermistor, since the battery cannot be overcharged or overdischarged. NTC thermistor temperature sensors are a critical component of lithium battery charging and safety.