Can Batteries Be Taken on Board?

Button cells in a key fob or 10,000 pounds of lithium ion?

The question is best answered by contacting the transport provider directly.

These restrictions can change at any time, so you need to get instructions from the airline you will be flying on....the rules vary from plane to plane, country to country and for international and domestic flights...

..."Aug 2, 2018 - The FAA forbids passengers from checking spare (uninstalled) lithium metal batteries, requiring them to be carried on. In addition, the FAA says that “all spare lithium batteries must be removed from the bag and kept with the passenger in the aircraft cabin,” when a carry-on bag is gate checked."...

https://thepointsguy.com/news/overheated-lithium-could-bring-down-plane/

https://www.swiss.com/ch/en/prepare/baggage/dangerous-goods

If they're attached to a box with a button on it, NO!

Look on the airlines website... they’ll list it there.

As both an Aero Engineer and a Pro Pilot , generally the answer has to be " No". Batteries can become electrolytically unstable too easily , especially when not stationary.

Normal Battery Operation is always switched , and heavy continuous vibration plays havoc with switches.

When a Battery Cell Short Circuits , lots of heat is produced. If it's un noticed , like in a Cargo Bay onboard an Aircraft , this can easily cause a Cargo Fire.

Generally , as a Rule , when Loading Aircraft Cargo , Batteries are separated from what device it is they power . This illiminates the short circuit / overheat problem at the source .

Many Cargo Loads of Laptop Computers have Spontaniously Ignited due to Lithium Batteries Overheating and self destructing in a Cargo Bay .

They have even blown holes in Airframes as they come apart , Lear Jets were prone to this , the early ones .

Battery Doors just exploding and leaving a huge hole , with no more Battery where there was one at Take Off .

Aircraft Rated Liquid Cells are Gell now , and highly Explosion Proof . ( GILL / CONCORDE ).

Conventional Automotive Type Wet Cells are still out there , and still very popular , but they have physical chemical limitations.

One is : They produce Hydrogen Gas , and Oxygen Gas , when they charge , and to a lesser degree , when they discharge as well'.

The Main Fuel in the NASA CHALLENGER ONE Disaster was these two Volatile Gasses

Hydrogen mixed with Oxygen . Explosively Volatile when mixed .