Intracellular device for lithium ion batteries

A battery module comprising:

• a first prefabricated thermally conductive substrate having a top surface;
• an array of wells disposed on at least one side of the first substrate;
• a plurality of battery cells each of which is at least partially enveloped within each of said well of the plurality of wells to propagate heat away from said plurality of battery cells;
• a dielectric sealant disposed between each of said plurality of battery cells and each of said respective well to electrically insulate a wall of each battery cell from the first prefabricated thermally conductive substrate;
• a first cell interconnect disposed above the first substrate and is electrically connected to the plurality of battery cells;
• wherein the first substrate is comprised of an electrically conductive material, and both the first terminal and the first cell interconnect are electrically coupled to the first substrate;
• a venting space disposed above the plurality of battery cells;
• and
• a first terminal electrically coupled to the first cell interconnect.