The　thermal　safety　of　lithium-ion　batteries　has　garnered　significant　attention　due　to　its　pivotal　role　in　the　field　of　new　energy.　In　this　work,　a　three-dimensional　electrochemical-thermal　coupling　model　based　on　the　P2D　model　was　established　for　predicting　the　thermal　performance.　The　charge-discharge　and　temperature　rise　experiments　via　18650　cylindrical　Li[Ni0.6Co0.2Mn0.2]O-2　/　graphite　batteries　are　designed　to　confirm　the　rationality　of　the　model.　The　simulation　results　show　that　the　highest　temperature　of　the　battery　surface　during　discharging　at　1　C　and　4　C　are　42.85　degrees　C　and　61.25　degrees　C,　and　the　experimental　results　are　42.50　degrees　C　and　62.85　degrees　C,　respectively.　The　electrode　heat　generation　mainly　comes　from　the　reaction　heat　of　cathode　and　anode　during　1　C　charge　process,　the　maximum　power　is　1.2　W　and　0.6　W,　respectively.　In　the　discharge　process,　the　cathode　dominates　the　reaction　contribution　of　1.02　W　and　the　reaction　heat　power　from　the　anode　is　only　0.016　W.　The　capacity　of　heat　dissipation　can　be　increased　by　enhancing　the　convective　heat　transfer　coefficient　and　air　velocity　within　a　reasonable　range.　The　proposed　electrochemical-thermal　coupling　model　is　valuable　to　evaluate　the　heat　behavior　and　promote　the　battery　development.