Battery system having an external thermal management system

An xEV electric vehicle battery system, comprising:

• a battery system housing with a bottom plate having one or more apertures;
• and
• a battery module disposed in an aperture of the one or more apertures, comprising:
• a battery module housing;
• a heat sink disposed proximate the aperture and under the battery module housing;
• at least one prismatic electrochemical cell disposed within the battery module housing above the heat sink and within the aperture of the bottom plate of the battery system housing, wherein the at least one prismatic electrochemical cell comprises terminals extending from a top surface of the at least one prismatic electrochemical cell;
• and
• a thermal interface layer having a first side in contact with a bottom surface of the at least one prismatic electrochemical cell and a second side substantially opposite the first side in contact with the heat sink, wherein the bottom surface of the at least one prismatic electrochemical cell is disposed generally opposite from the top surface, and the thermal interface layer is configured to enable heat transfer from the bottom surface of the at least one prismatic electrochemical cell to the heat sink;
• and
• a clamping system having a clamping bar and at least one side clamp, wherein the clamping bar is configured to exert a clamping force to clamp the at least one prismatic electrochemical cell to the heat sink via the at least one side clamp, wherein the at least one side clamp is a part of the battery module housing, wherein the clamping system comprises a weld nut positioned on the heat sink and a fastener disposed through a hole in the clamping bar and threaded into the weld nut to couple the clamping bar to the heat sink, and wherein the fastener is configured to urge the clamping bar downwardly toward the heat sink as the fastener is tightened into the weld nut.