Or, rather, there is a risk of overheating and Nikon decided not to take any risk and to recall some of the EN-EL15 (batteries used on D700, D7000, D800, D800E and V1).
The only batteries that may be replaced hold the letter E or the letter F in 9th position in their serial number.
EN-EL15 Rechargeable Li-ion Battery Service Advisory (Nikon).