Overview
- The Nature Energy study, published Sept. 10–11, 2026, analyzed more than three years of real-world data from passenger cars with NMC cells and buses with LFP cells to measure cell-level aging.
- Researchers found packs used about 80.7% of lifetime energy in cars and 72.9% in buses, meaning roughly 19.3% to 27.1% of potential energy is left unused when the fastest-aging cells force pack retirement.
- A small number of faster-aging cells set pack limits because a low-capacity cell can hit charging voltage limits or a high-resistance cell can hit safety limits during discharge, which ends pack service early.
- The team combined battery-model identification with neural networks to standardize conditions and estimate per-cell capacity and resistance changes, and they reported state-of-charge imbalance reduced usable charged capacity by less than about 2%.
- The study says practical steps—tighter manufacturing consistency, smarter cell grouping, improved balancing and thermal management, and reconfigurable pack designs—could recover energy, length pack life, lower fleet costs and change reuse or recycling economics.