Recently, the US Department of Transportation and the US Federal Aviation Administration (FAA) issued an interim regulation prohibiting the transport of lithium-ion batteries on passenger flights. It also requires that the battery on the cargo plane does not exceed 30%. In most cases, passengers can still carry battery-using equipment (including spare batteries) on the go, but not just put a separate battery pack in the aircraft cabin.
US Transportation Secretary Elaine Chao said this is a security measure, and the FAA has been urging airlines to reconsider the issue of carrying batteries because of the risk of fire with lithium-ion batteries. In theory, this ban reduces the likelihood of accidents and increases the safety of passengers on flights.
The main reason for the cargo ban is the person who orders the battery, because the batteries may need to wait for a special cargo flight.