Reply to post:

"Also, the airlines state, that devices with Lithium batteries should never be checked and only taken as hand luggage"

I thought that depended on whether it's installed in equipment or not. From:

https://www.faa.gov/about/office_org/headquarters_offices/ash/ash_programs/hazmat/passenger_info/media/Airline_passengers_and_batteries.pdf

Q2. What kinds of batteries does the FAA allow in checked baggage (including gate-checked bags)?

A2. Except for spare (uninstalled) lithium metal and lithium-ion batteries, all the batteries allowed in carry-on baggage are also

allowed in checked baggage. The batteries must be protected from damage and short circuit or installed in a device. Battery-powered

devices—particularly those with moving parts or those that could heat up—must be protected from accidental activation. Spare

lithium metal and lithium ion/polymer batteries are prohibited in checked baggage—this includes external battery packs. Electronic

cigarettes and vaporizers are also prohibited in checked baggage. “Checked baggage” includes bags checked at the gate or planeside.