The back clip battery is a special charging treasure for a certain model. It is equipped with ultra-thin lithium battery and charging and discharging circuit. The back clip battery and the matching model of the mobile phone can be "seamless" in appearance without affecting the camera and fingerprint functions. The installation and use of the back clip battery is to insert the mobile phone into the back clip battery, install the battery installation instructions, disassemble the top of the back clip battery, insert the mobile phone, align the tail plug of the mobile phone with the back clip battery interface, and install the battery top cover to combine the mobile phone with the back clip battery.