In the era of the Internet of Things, IoT, the best security is to disconnect the Internet and remove the battery?

Can they invade our privacy with a smartphone off and with a TV off?. It seems that we do believe the latest papers published by Wikileaks on the procedures of the CIA. Smart devices appear to use the battery to emit data, even if they are not turned on. That’s why I wonder if in the era of implementing internet in all the objectives of our personal and professional lives the best way to guarantee our privacy is to turn off the Internet … and now … remove the battery from the mobile. And this can not always be done, because on many smartphones and laptops the battery is soldered to the motherboard.