After jailbreaking, you can install iBadteryinfoPro 2 plug-in, and you can view battery data including battery capacity, maximum capacity, charging times, battery temperature, battery serial number and so on.
If the device has escaped from prison, the method is
Open Cydia to add software Source: repo.hackyouriphone.org.
Then search and install the ibatteryinfopro2 plug-in.
Hope to adopt