The　performance　of　Lithium-ion　batteries　(LIBs)　is　seriously　affected　by　temperature　rise　and　mechanical　degradation　during　the　charge　or　discharge.　In　this　work,　a　fully　coupled　thermomechanical　model　with　the　total　heat　generation　rate　is　developed　to　analyze　the　mechanism　of　the　temperature　rise　and　stress　distribution.　Then　numerical　simulations　are　performed　to　show　the　evolution　of　temperature　and　stress　for　18650　LIBs.　The　comparisons　of　the　surface　temperature　evolution　between　the　present　model　and　experimental　results,　and　the　temperature　variation　with　radius　between　the　present　model　and　the　pure　thermal　model　are　made,　respectively.　Finally,　the　influences　of　some　design　parameters　upon　the　Li-ions　concentration　and　the　stress　are　discussed.　The　numerical　results　show　that　the　present　model　is　more　validated　against　the　pure　thermal　model,　and　the　temperature　and　stress　will　be　reduced　if　the　positive　electrode　particle　radius,　the　volume　fraction　of　the　positive　active　material　and　the　initial　electrolyte　salt　concentration　are　decreased,　or　the　positive　electrode　thickness　is　increased　which　will　provide　some　guides　for　the　design　of　LIBs.　©　2023　American　Society　of　Civil　Engineers.