Case study of backup power supply for portable Bluetooth player

With the development of modern society, entertainment methods have begun to shift towards outdoor activities, and many entertainment venues have also begun to lean towards outdoor activities. Portable Bluetooth player is one of the devices that generate entertainment outdoors. With its compact and portable design, high-quality speaker effects, as well as the integration of a home electric player and special Bluetooth transmission function, it has become the first choice for outdoor entertainment equipment in modern society. Due to the requirement of portability, providing a safe, efficient, stable, portable, and sufficient backup power solution for portable Bluetooth players has become an important guarantee for people's long-term outdoor entertainment. With its unique advantages, portable Bluetooth player backup batteries have become the preferred power solution for outdoor entertainment devices.

1. Design requirements for lithium battery backup portable Bluetooth player.

The working current of the player is relatively small, but to achieve continuous operation of the device, it requires at least 8 hours of battery working time. The battery should have overheating protection function, and the finished battery should comply with UL2054 certification requirements. The weight of the battery must be controlled within 200g. For this reason, our company uses imported Samsung batteries, which have advantages such as high energy ratio, light weight, small size, long service life, high safety, high voltage, and good consistency. The overcurrent protection value of the lithium battery is 15A, the maximum continuous working current is 2.2A, and the charging capacity is 2.2Ah, fully meeting the time and power requirements of the player. The specific design requirements are as follows.

1) Lithium battery model design requirements: 18650-3S1P/2.2 Ah/11.1 V.

2) Circuit design requirements.

1.1.1.1.1.1 Overcharge protection voltage for individual batteries: 4.35± 0.25V

2. Single battery regeneration overload protection voltage: 4.15&plus 0.50V

3. Single battery overload protection voltage: 2.40± 0.08V

4. Overdischarge recovery voltage of individual batteries: 3.00 and 0.10V.

5. 10-17A

6. 70 and 5 minutes

7. The finished battery has short-circuit and reverse charging protection.

3) Design requirements for battery cycle life: 300-500 cycles (according to the national standard for charging and discharging)

4) Design requirements for battery size: refer to the size of the finished battery

2. Design diagram of a portable Bluetooth player as an alternative to lithium batteries.

1) Protective Circuit Board (PCM): This is mainly a protective circuit designed for rechargeable lithium batteries. Due to the chemical characteristics of lithium batteries themselves, it is necessary to provide intelligent power calculation, overcharging, over discharging, circuit short circuits, and overcurrent protection functions. To avoid hazards such as combustion and explosion.

2) Protection IC: The main protective function chip in the design scheme, which monitors online the functions of overcharging, discharging, overcurrent, short circuit, etc. of the battery cells, ensuring their safe operation., Stable and effective range.

3) Temperature switch: mainly designed for temperature protection function. When the temperature of the battery itself reaches the range of 70+5 ℃ due to other abnormal issues, the temperature switch will protect the temperature

4) 18650 lithium-ion battery:/18650/2200 mAh/3.7V lithium-ion battery (Samsung).

5) Field effect field-effect transistor (MOSFET): As a switch in the protective circuit, MOSFET will always prevent the voltage at both ends of the load from rising or falling, thereby ensuring voltage stability.

6) Battery packaging: shrink PCV