Battery module having a cell assembly

A battery module comprising:

• an enclosed housing comprising a first interior surface and a second interior surface;
• a cell assembly disposed within a first interior space of the housing, the cell assembly comprising a plurality of prismatic lithium ion battery cells arranged in a cell stack, each battery cell of the plurality of prismatic lithium ion battery cells comprises a substantially inflexible packaging, the cell stack comprising:
• a first column comprising a first half of the plurality of prismatic lithium ion battery cells;
• a second column adjacent to the first column comprising a second half of the plurality of prismatic lithium ion battery cells;
• a first end;
• and
• a second end disposed opposite the first end;
• an electrically and thermally insulating wall disposed between the first end of the cell stack and a first interior surface of the housing, the electrically and thermally insulating wall comprising a first surface adjacent to the first end of the cell stack and a second surface opposite the first surface, the second surface being adjacent to a second interior space of the housing defined at least in part by the second surface of the electrically and thermally insulating wall and the first interior surface of the housing;
• a circuit board disposed in the second interior space of the housing;
• wherein the first interior space of the housing is defined at least in part by the first surface of the electrically and thermally insulating wall and the second interior surface of the housing;
• and
• wherein the electrically and thermally insulating wall comprises an intentional weak point configured to deform or break due to an uncontrolled expansion or rupture of a battery cell of the plurality of prismatic lithium ion battery cells to enable the battery cell to expand toward the second interior space of the housing.