A battery module includes a battery cell, a bus bar, and a multilayered cell sense flex circuit having a senseline tab containing a portion of a senseline. The flex circuit determines a battery cell voltage. The bus bar has surface projections, possibly with a variable height and/or width, such that the bus bar penetrates into the tab at least as far as the senseline. Adhesive material may be used on the welded joint. A method of manufacturing the battery module includes forming, in the bus bar, one or more surface projections, e.g., multiple projections having the variable height and/or width, positioning a senseline tab of the flex circuit adjacent to such projections, and joining the tab to the surface projections such that the projections penetrate at least partially into the flex circuit at least as far as the senseline.