Disassemble the bottom shell and tighten the screws on both sides. A plastic support frame is used inside to insulate and protect the battery core and PCB board, and the battery core is also pasted with foam rubber buffer support. Hollow design on the back of the plastic support frame to avoid heat accumulation.

The plastic frame is provided with isolation boards and LED light isolation grooves, and the area where the battery cells are located is fixed with double-sided adhesive tape.

The front view of the PCB board, the capacitor is reinforced with glue, and the right side is equipped with a shielding cover for the buck-boost circuit area.

A look at the back of the PCB board. Vias are designed in many places, insulating tape is pasted at the connection between the battery cell and the circuit board, and the thermistor pad is glued for reinforcement.

Lishen battery close-up, the specifications are 3.85V, 5Ah/19.25Wh, and the charging limit voltage is 4.4V.

A thermistor is installed between the two cells for temperature monitoring.

A close-up of the nickel weld.

Screen printing 66BJM battery protection IC

Screen printing 2002 battery protection tube, double NMOS

TI BQ29200 2-string lithium battery balance IC, and has overvoltage protection function, used for the balance function of 2-string batteries in the mobile power supply.

TI BQ29200 details.

Silkscreen X19b6.

The mobile power buck-boost chip adopts SC8815 of Nanxin Semiconductor. The chip's I²C programmable charge current and charge voltage, programmable discharge output voltage, programmable input / output current limit; built-in 10-bit ADC;

with undervoltage protection, overvoltage protection, overcurrent protection, short circuit protection and thermal shutdown Various protection functions such as power-off protection; single chip completes charge/discharge control and supports various power conversions.

A close-up of the 2R2 inductor, reinforced with glue. There are a total of four screen-printed 1VA177 MOS tubes on both sides of the inductor, forming an H-bridge for synchronous buck-boost.

The other two are close-ups, four of which cooperate with Nanxin SC8815 to form an H-bridge buck-boost circuit, which is responsible for bidirectional charging and discharging of mobile power.

Silk screen 94B438KUN, from ABOV modern microcontroller, I2C interface directly communicates with Southchip SC8815 buck-boost controller, used for mobile power port control and power display and other functions.

Screen printing DDO 3A9 regulator IC.

The power switch key is soldered. Close-up of LED lights. The screen printing 2228S is actually Runshi RS2228 analog switch.

Silk screen P1 GD switch tube, used for port power switching.

USB-C port filter capacitors, all specifications are 20V 120μF, from YMIN. YMIN VPX series polymer solid aluminum electrolytic capacitors have the characteristics of high reliability, low ESR, and high allowable ripple current.

The working temperature range is -55°C-105°C, and it still has a life span of 2000 hours even in a working environment of 105°C. At the same time, this series of capacitors has the characteristics of miniaturization, and adopts the form of mounting, which can help realize the thinning and thinning of products when used in mobile power supplies.

Wuxi Lixinwei ET9539AM input overvoltage protection switch, withstand voltage 28V, CSP12 package, used for mobile power input overvoltage protection.

Silk screen M26A, TVS protection element, used to suppress voltage surge. USB-A port output filter solid capacitor. The output protection tube of the USB-A port, silk screen 8205.

3904 small signal transistor. Close-up of the USB-A female seat, sinking plate through-hole welding. All disassembled.