When a cell phone is turned off, it cannot be tracked, as it is no longer communicating at this point.
When you search Google for:
“Can my phone be tracked when turned off?”
You will get results that are discussing location services being off, and not the phone itself.
I think this is what’s causing some confusion here.
There is no need to remove a SIM card, take out the battery, or take any other unnecessary measures.
Off is off, and there will be no further ping, other than a final one when the phone is powered down.