A smart watch is a smart watch with a built-in smart system. It is equipped with a smart phone system and connected to the Internet, so all functions can be used. They can synchronize calls, text messages, emails, photos, music and other phone calls. Smart watches usually use high-performance polymer batteries to ensure continuous, efficient and stable operation of the product. In order to meet the long-term reliable and safe use of users.

1. Battery design requirements for smart watches

According to customer requirements and specifications, design a battery pack that matches the host, and incorporate polymer batteries and safety protection into the solution. In the design process of the entire program, the goal is to achieve the most perfect combination with the host, to ensure the safety of the battery, battery and the entire system, and first to meet the corresponding design regulations and certification regulations. thoughtful. In order to ensure the safety and reliability of polymer batteries, multilayer protection must be integrated inside the battery pack to prevent lithium batteries from being damaged by overcharging, overdischarging, or short-circuiting.

1) Polymer battery model: 403040PL 3.7V 450mAh

2) Circuit design requirements.

1. Single battery overcharge protection voltage: 4.30±0.25V

2. 4.15 ± 0.50V

3. Single battery overload protection voltage: 2.8 ± 0.08V

4. Single battery over-discharge recovery voltage: 3.00±0.08V

5. Combined battery over-current protection value (10 milliseconds): 2~4A

6. The finished battery also has short circuit and reverse charging protection.

7. Design requirements for battery cycle life: 300~500 times (national standard charging and discharging standards

8. Design requirements for battery size: refer to the computer housing in the lobby

2. Schematic diagram of smart watch battery design

1) Protective plate (PCM): It is mainly used to protect polymer batteries. Due to the chemical characteristics of lithium batteries, it must provide protection functions such as overcharge, overdischarge, short circuit and overcurrent to prevent combustion, explosion and other hazards.

2) Protection IC (Protection IC): The main protection function chip in the design scheme, online monitoring of the battery's overcharge, overdischarge, overcurrent, short circuit and other functions , So that the battery can operate safely. , Stable and effective range. At the same time, measure battery capacity, temperature, remaining time alarm and other parameters.

3) Polymer lithium ion battery: 403040PL 3.7V 450mAh lithium polymer battery.

4) Field Effect Switch Field Effect Transistor (MOSFET): As a switch in the protection circuit, MOSFET will always prevent the voltage across the load from rising or falling to ensure voltage stability.

5) Battery packaging: sealed and connected to the host