1) The design requirement for smart watches Li-Polymer Battery
According to the requirements of consumers, in order to realize the Information Sharing between battery packs and the host engine, we designed a host supporting polymer battery pack to integrate the polymer Battery and Battery safety protection performance together. Based on the safety of Batteries, Battery packs, and the entire system in this whole design program, the design meets the requirements of related design and certification regulations. Thus, in order to ensure the Safety and reliability of polymer Battery, we design Multi-layer protection in internal battery pack to avoid short circuit or damage caused by Overcharge, over discharge of Lithium Battery.1. Li-Polymer Battery Model: 403040PL 3.7V 450mAh
2. Li-Polymer Battery Circuit design requirement
A.single battery overcharge protection voltage: 4.28±0.25V
B.single battery overcharge recovery voltage: 4.10±0.50V
C.single battery over discharge protection voltage: 2.80±0.08V
D.single battery over discharge recovery voltage: 3.00±0.10V
E.Combined battery over current protection (10ms):4~8A
F.Battery over heat protection (recoverable): 75±5℃
G.Finished battery can be protected from the harm of short circuit and reverse charge.
H.Battery cycle life requirement: 300~500times (national charge and discharge standards)
I.Battery dimension design requirement: Referring to the host shell，and can be customized by customers’ requirements.
2) The design for smart watches Li-Polymer Battery
1. Li-Polymer Battery Protection Board (PCM): designed for wireless oximetry polymer battery to protect circuit, the protection board needs to provide smart power calculation, overcharge, over discharge, short circuit, over current protection to avoid the hazard of burning and explosion because of its chemical properties.2. Li-Polymer Battery Protection IC: The main function of this design is to protect chip, and constantly monitor the situation of overcharge, over discharge, over current, short circuit occurring, so that the chip can operate in a safe, stable and efficient condition.
3. Li-Polymer Battery cell: 403040PL 3.7V 450mAh
4.MOSFET: MOSFET acts as a switch in the protection circuit, and balances the voltage across the load.
5. Li-Polymer Battery packaging: Sealed and fixed with high temperature adhesive tape on both sides.