This　study　provides　an　alternative　solution　to　enhance　melting　performance　of　phase　change　material　by　designing　a　novel　V-shaped　fin.　Nineteen　cases　with　different　V-shaped　fins　is　designed,　the　effects　of　angle,　length,　number　and　arrangement　of　fins　on　heat　transfer　performance　of　heat　storage　unit　were　studied.　The　response　surface　method　was　used　to　optimize　the　structure.　Assessments　on　the　melting　fraction,　temperature　field,　velocity　distribution,　and　uniformity　for　melting　are　made.　Results　demonstrate　that　due　to　the　effect　of　natural　convection,　the　upper　part　melting　speed　is　accelerated,　resulting　in　a　significant　difference　in　the　heat　storage　efficiency　between　the　upper　and　lower　half　regions.　The　melting　time　of　the　lower　half　of　the　heat　storage　unit　without　fins　accounting　for　62.5　%　of　the　whole　melting　time.　Based　on　the　above　analysis,　more　and　longer　fins　should　be　considered　to　be　arranged　at　the　bottom　of　the　heat　storage　unit　to　improve　the　heat　storage　performance　of　the　system.　As　noticed,　the　structure　parameters　change　of　fins　has　a　significant　effect　on　reducing　the　melting　time　of　the　whole　phase　change　material.　It　can　be　found　that　there　are　optimal　values　for　the　structure　parameters.　The　optimal　fin　structure　parameters　(fin　angle　α　=　55°,　fin　length　L1　=　9　mm,　fin　number　N　=　5,　branch　angle　β　=　55°,　and　branch　length　L3　=　3)　obtained.　The　heat　storage　efficiency　of　the　optimal　fin　structure　was　2.57　times　that　without　fins,　and　the　heat　storage　time　was　shortened　by　61.05　%.　To　be　conclusive,　adding　fins　to　a　heat　exchanger　is　more　beneficial　than　no　fins,　saving　more　energy　storage　time.　©　2022　Elsevier　Ltd