power bank containing a lithium ion battery must be packed in carry-on bags. Also only power bank lower than 100 Watt-hour (20 000 mAh) is allowed in carry-on. Power bank is most likely not allowed in checked baggage due to a risk of autoignition
Please note that airport security officers may decline taking an item on a plane if it may cause a threat.
Rules may slightly differ depending on the airport and circumstances.