Battery including thermally conductive filler material with thermal runaway containment function

A battery comprising:

• a housing having an inner surface that at least partially defines an interior of the housing;
• a battery cell stack disposed within the interior of the housing such that a gap exists between the battery cell stack and the inner surface of the housing, the battery cell stack including:
• a first battery cell group including at least two adjacent battery cells;
• a second battery cell group including at least two adjacent battery cells;
• and
• a partition that physically separates the first battery cell group from the second battery cell group,
• wherein each of the battery cells of the first battery cell group and the second battery cell group includes an electrode assembly sealed within a case and a positive electrode tab and a negative electrode tab electrically coupled to the electrode assembly and extending from the electrode assembly outside the case, and
• wherein the positive electrode tabs and/or the negative electrode tabs of the battery cells extend into the gap between the battery cell stack and the inner surface of the housing;
• and
• a filler material that fills the gap and provides a thermally conductive pathway between the positive electrode tabs and/or the negative electrode tabs of the battery cells and the inner surface of the housing,
• wherein the filler material includes a thermally conductive particulate component distributed throughout a polymeric matrix component,
• wherein the thermally conductive particulate component accounts for, by volume, greater than 5% and less than 50% of the filler material, and
• wherein the polymeric matrix component is configured to thermally decompose at temperatures greater than an upper operating temperature of the battery cells to form a thermal and physical barrier that inhibits heat transfer between the first battery cell group and the second battery cell group via the gap.