I’ve heard that the Galaxy Z Flip is equipped with a dual battery. Is it safe?

Samsung equipped the Galaxy Z Flip with a sophisticated dual-battery system that works as one, and intelligently powers the phone. 

The goal was to make the Galaxy Z Flip as thin as possible while accommodating two displays and a better battery capacity. To achieve this, Samsung installed a battery on each side of the display and created new battery management technology to detect remaining power and to control the flow. Each battery comes with a temperature sensor to prevent overheating. All Samsung smartphones undergo a rigorous 8-point internal inspection test, and are constantly held to Samsung’s state-of-the art quality standards.