Electric powertrain system with multi-module battery pack and intermodule thermal barrier

A method for mitigating a thermal runaway event in a battery pack having a plurality of battery modules, the method comprising:

• providing a battery tray having a battery tray floor configured to support the battery modules from below, wherein the battery tray is configured as a grid formed by longitudinal outer walls extending along a length of the battery tray and intersected by equally-spaced transverse inner walls, wherein the battery tray defines multiple battery tray compartments, each of the battery tray compartments being configured to receive therein and support thereon a respective one of the battery modules;
• identifying a heat transfer path through the battery tray between an adjacent pair of battery modules;
• arranging the plurality of battery modules on the battery tray;
• fastening the plurality of battery modules to the battery tray to thereby construct the battery pack, including connecting the plurality of battery modules to a respective one of the transverse inner walls via a set of module tabs and fasteners;
• and
• arranging a thermal barrier on a respective upper surface of the transverse inner walls in the heat transfer path between the adjacent pair of the battery modules, the thermal barrier having a thickness of at least about 1 mm and a thermal conductivity of less than about 4 W/m-K, such that the thermal barrier blocks the heat transfer path, wherein the heat transfer path passes through the module tabs and the fasteners connected thereto.

An electric powertrain system comprising:

• a rotary electric machine having phase leads and an output member;
• a driven load coupled to the output member of the rotary electric machine and powered thereby;
• a multi-module battery pack having:
• a battery tray having a battery tray floor and configured as a grid formed by longitudinal outer walls extending along a length of the battery tray and intersected by equally-spaced transverse inner walls;
• a plurality of battery modules each arranged in a respective battery tray compartment of the battery tray and supported from below by the battery tray floor, such that a heat transfer path exists between an adjacent pair of the battery modules through the battery tray, wherein each respective battery module of the plurality of battery modules includes a set of module tabs connected via fasteners to a respective one of the transverse inner walls;
• and
• a thermal barrier attached to a respective upper surface of the transverse inner walls of the battery tray, arranged in a predetermined heat transfer path through the battery tray, and having a thermal conductivity of less than about 4 W/m-K, such that the thermal barrier is configured to block the heat transfer path during a thermal runaway event of one of the adjacent pair of battery modules and thereby mitigate the thermal runaway event, wherein the predefined heat transfer path passes through the module tabs and the fasteners connected thereto;
• and
• a power inverter module connected to the multi-module battery pack and to the phase leads of the rotary electric machine, wherein the power inverter module is configured to energize the rotary electric machine via the multi-module battery pack to thereby deliver motor torque to the driven load.