Case study of portable solar backup power supply

Mobile backup power supply solves the outdoor power supply problem of digital products, using renewable energy from nature to convert energy storage or household energy storage, and solves the outdoor power supply and power supply problem of mobile digital products. The product features lightweight, high efficiency, and diversity.

1. Design requirements for portable solar backup power supply.

Portable solar backup power supplies use solar energy as a conversion source, converting solar energy into electrical energy, and storing it through lithium batteries to provide outdoor power for mobile digital products. The entire product uses a single core high-capacity lithium battery as energy storage, and the charging adopts a two-layer charging mode: the solar panel is charged by sunlight, and the charger adopts a two-layer charging mode. The output terminal has a 5V output. The maximum output current can reach 2A, which can meet the power requirements of relevant digital products. Accurate LED display, in the form of LED lights, effectively displays the remaining battery power to users in an accurate percentage, achieving efficient and intuitive purposes.

1) Lithium battery model design requirements: 6535134/3.4 Ah/3.7 V.

2) Solar panel conversion parameters: 5V/350mA

3) Partial protection circuit design requirements.

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. Overcurrent protection value of 5-8A (10ms).

6. Overheat protection value (renewable): 70 and 5 degrees

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

4) Design requirements for battery cycle life: 300-500 cycles (according to national charging and discharging standards)

5) Design requirements for battery size.

2. Design diagram of portable backup power supply.

1) Protection IC: Mainly designed to protect rechargeable lithium batteries. Due to the chemical properties of lithium batteries themselves, they must provide protective functions such as overcharging, over discharging, short circuits, and overcurrent. To avoid hazards such as burns and explosions.

2) Partial voltage reduction module: Solar panel (5V/350mA), 5V charger input voltage reduction module, realizing specific pre charging, constant current and constant voltage charging modes of sequential charging function based on the characteristics of lithium batteries.

3) Boosting module part: Adopting a stable 5V output circuit, the maximum output current can reach 2A.

4) Charger module section: Use Tonghe 5V/1.5V charger

5) LED display section: Use voltage comparison to display battery level.

6) Solar panel section: converts solar energy into electrical energy, with output parameters of 5V/350mA

7) Lithium battery cells: PL6535134/3.4Ah/3.7V (ATL).