Battery　has　drawn　much　more　attention　due　to　the　accelerating　development　of　Electric　Vehicle　(EV)　and　Plug-in　Hybrid　Electric　Vehicles　(PHEV)　for　sustainable　mobility.　It　is　worthwhile　to　study　the　dynamic　model　of　battery　in　order　to　achieve　better　performance　in　power　management.　This　paper　proposes　a　nonlinear　dynamic　battery　model　for　PHEV　power　management.　First,　an　existing　RC　equivalent　circuit　is　used　to　simulate　the　dynamics　of　the　battery　states　with　respect　to　the　input　current.　Then,　a　concept　of　nonlinear　hysteresis　degree　is　introduced,　and　is　adopted　to　implement　the　mathematical　description　of　the　battery　nonlinear　boundary　and　scanning　hysteresis.　Finally,　the　dynamics　and　the　nonlinear　boundary　(scanning)　hysteresis　are　integrated　into　a　comprehensive　battery　model　with　an　affine　nonlinear　state-space　equation.　The　effectiveness　of　the　proposed　model　is　verified　using　some　simulation　tests.　Copyright　©　2009　by　ASME.