Charging efficiency at high state-of-charge (SoC) levels is influenced by battery chemistry, design, and operating conditions, with variations possible between brands due to differences in cell engineering and management systems. Key findings from available data:
1. Lithium-ion Chemistry
Li-ion batteries generally achieve over 99% coulombic efficiency (CE) under optimal charging conditions, but efficiency drops at high SoC due to increased heat and charge acceptance challenges. Brands like Panasonic, LG, and Samsung demonstrate improved CE with cycling (e.g., rising from 99.1% to 99.9% over 15–30 cycles in lab tests of 18650 cells), suggesting that maturity in cell design mitigates efficiency loss.
2. High SoC Effects
Efficiency declines as batteries approach full charge due to:
- Heat generation requiring active cooling
- Increased internal resistance during voltage tapering
- Slow charge acceptance in the final saturation phase
3. Brand-Specific Variations
While direct comparisons between brands are not explicitly documented, differences may arise from:
- Thermal management systems: Better cooling in premium brands maintains efficiency at high SoC
- Charging algorithms: Custom voltage/current curves (e.g., Tesla’s 95% efficiency with Level 2 charging vs. 85% for generic 120V systems)
- Cell construction: Thicker SEI layers in lower-quality cells may accelerate efficiency loss
Practical Implications
Efficiency optimization strategies like partial charging (30–70% SoC) and moderate current levels apply universally, but high-end brands with advanced battery management systems (BMS) likely exhibit smaller efficiency drops at high SoC compared to budget alternatives.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-does-the-charging-efficiency-at-high-soc-levels-compare-between-different-brands-of-batteries/
