Based　on　the　combination　of　transfer　matrix　method　and　Biot　theory,　the　acoustic　wave　reflection　and　transmission　coefficients　was　theoretically　calculated　at　the　liquid/solid　interfaces　between　two-phase　porous　lithium-ion　battery　and　liquid　media.　Meanwhile,　the　influence　of　the　swing　characteristics　of　lithium-ion　on　the　mechanical　properties　of　electrode　was　considered,　and　the　theoretical　prediction　of　electrode　density　and　elastic　modulus　under　different　states　of　charge　is　realized.　The　angle　spectrum　and　frequency　spectrum　of　reflection　and　transmission　coefficients　for　corresponding　state　lithium-ion　battery　can　be　obtained　by　the　proposed　method.　Then,　a　frequency　domain　simulation　model　of　the　multi-layered　porous　lithium-ion　battery　was　established,　and　the　reflection　and　transmission　coefficients　obtained　by　finite　element　method　for　lithium-ion　battery　are　consistent　with　those　results　by　the　proposed　approach.　For　the　case　of　multi-cell　lithium-ion　battery,　the　relationship　between　reflection/transmission　coefficients,　oblique　incident　angle　or　frequency　under　different　azimuth　angles　are　analyzed.　The　shift　law　of　the　characteristic　point　curves　in　the　angle　spectrum　and　frequency　spectrum　with　the　change　of　the　state　of　charge　of　the　lithium-ion　battery　is　analyzed.　It　provides　a　theoretical　basis　for　the　ultrasonic　measurement　of　the　state　of　charge　of　lithium-ion　batteries.　©　2023　Acta　Acustica.