Abstract: Exemplary thermal barrier systems are provided for traction battery packs. Exemplary battery thermal barrier systems may include one or more thermal barrier structures that are positioned between neighboring groupings of battery cells of a cell bank and/or elsewhere within a battery array of the traction battery pack. The thermal barrier structures may include a foam-insulation-foam multi-layer structure, an insulation-foam-insulation multi-layer structure, or an insulation-foam multi-layer structure. The thermal barrier structures are designed to manage cell-to-cell transfers of heat and electrical energy during battery thermal events.