The present disclosure relates to methods and systems to manage thermal runaway issues in energy storage systems. Exemplary embodiments include methods and systems having a compressible thermal barrier. The compressible thermal barrier is tailored in size (e.g., thickness, volume, etc.) to prevent thermal propagation between adjacent cells, modules and/or packs when a portion of an energy source has experienced a thermal event. The methods and systems mitigate thermal propagation such that a cell adjacent to a compromised cell (e.g., actively combusting cell) does not experience thermal runaway as it is shielded from dissipating heat and does not surpass a critical temperature. The present disclosure further relates to a battery module or pack with one or more battery cells and the compressible thermal barrier placed between adjacent cells.