Flexible voltage nested battery module design

A battery module comprising:

• a cell casing;
• a plurality of battery cells disposed within the cell casing, the battery cells each having its own terminal, the terminals having top and peripheral sides portions;
• and
• at least one buss bar segment that provides an electrical connection between a group of the battery cells, the at least one buss bar segment being extended across longitudinal ends of the group of battery cells to contact the tops of the terminals, and
• wherein the peripheral sides of the terminals are unobstructed by the at least one buss bar segment such that a laser can be pointed towards the peripheral sides to weld the terminals to the at least one buss bar segment, and
• wherein the terminals each comprise at least two peripheral sides, and the buss bar segment comprises protrusions that contact the terminals, each protrusion having a first side and a second side that are substantially aligned with the at least two peripheral sides of the respective terminals.