Battery Pack for PHEV segmentation by type distinguishes three principal chemistries: lithium‑ion (including NMC, NCA, LFP), nickel‑metal hydride (NiMH), and emerging solid‑state configurations. Lithium‑ion dominates due to its superior gravimetric energy density (150–250 Wh/kg) and declining cost, accounting for roughly 80 % of total pack volume in the PHEV market. Within lithium‑ion, NMC/NCA variants are preferred for high‑performance models, while LFP gains share in cost‑sensitive segments because of lower material expense and enhanced thermal stability. NiMH, once prevalent, now represents less than 10 % of shipments, confined to legacy platforms where legacy battery management systems persist. Solid‑state packs, still in pilot production, contribute under 5 % but are projected to influence future market composition as automotive OEMs target higher energy density and safety thresholds. The relative weight of each type directly shapes overall market size, as pack cost, performance envelope, and lifecycle affect OEM adoption rates and total units sold.