At　present,　battery　energy　storage　systems　are　available　in　increasingly　higher　voltage　levels　and　capacities.　The　traditional　topology　cannot　meet　the　demand,　and　the　converter　needs　to　adopt　the　multilevel　voltage　topology.　In　this　paper,　an　exquisite　equivalent　modeling　method　for　energy　storage　modular　multilevel　converter　(MMC)　is　proposed.　In　this　method,　the　model　parameters　of　the　bridge　arm　and　battery　pack　are　obtained　by　the　Kalman　filtering　algorithm　and　improved　recursive　least　square　method.　Secondly,　the　whole　bridge　arm　is　equivalent　by　using　Thevenin＇s　theorem,　and　the　simplified　equivalent　modeling　of　the　whole　bridge　arm　is　realized.　Time　domain　simulation　results　show　that　this　method　can　achieve　fine　equivalent　modeling　of　energy-storage　MMC,　reduce　the　number　of　electrical　nodes　in　the　simulation　circuit,　and　greatly　reduce　the　amount　of　calculation.　©　Published　under　licence　by　IOP　Publishing　Ltd.