System and method for battery modules having terminal block assemblies with drainage channels

A battery module, comprising:

• a polymer housing defining a water-tight interior volume and a first receptacle;
• a plurality of lithium-ion battery cells disposed within the water-tight interior volume of the polymer housing;
• a first terminal block assembly sealed within the first receptacle of the polymer housing to define a first major terminal of the battery module, wherein the first terminal block comprises:
• a first terminal post having a first post portion and a first base portion that extends outward from a central axis of the first post portion;
• a first bus bar mechanically coupled to the first base portion, wherein the first bus bar includes a first U-shaped trough disposed near the first terminal post and a first hairpin bend that is disposed adjacent to the first U-shaped trough and that extends in a direction opposite the first U-shaped trough, and wherein the first bus bar is electrically coupled to the first plurality of cell terminals of the plurality of lithium-ion battery cells;
• and
• a first polymer portion overmolding at least the first hairpin bend and the first U-shaped trough to form a first drainage channel near the first terminal post, wherein the U-shaped trough is disposed near an interface between the polymer portion and an exposed base of the bus bar surrounding the terminal post, wherein the exposed base of the bus bar is not overmolded by the polymer portion.