To maximize the lifespan and performance of lithium-ion batteries, proper charging habits are critical. Recent studies and industry recommendations highlight distinct charging strategies for two widely used battery types: Nickel-Cobalt-Manganese (NCM or ternary lithium) batteries and Lithium Iron Phosphate (LFP) batteries. Here’s what users need to know:
Key Recommendations
- NCM Batteries: Charge to 90% or below for daily use. Avoid full charges (100%) unless necessary for long trips.
- LFP Batteries: While daily charging to 90% or below is ideal, a weekly full
- charge (100%) is required to recalibrate the State of Charge (SOC) estimation.
Why Avoid Full Charges for NCM Batteries?
1. High Voltage Stress Accelerates Degradation
NCM batteries operate at a higher upper voltage limit compared to LFP batteries. Fully charging these batteries subjects them to elevated voltage levels, accelerating the consumption of active materials in the cathode. This irreversible process leads to capacity loss and shortens the battery’s overall lifespan.
2. Cell Imbalance Risks
Battery packs consist of numerous cells with inherent inconsistencies due to manufacturing variations and electrochemical disparities. When charging to 100%, certain cells may overcharge, causing localized stress and degradation. While Battery Management Systems (BMS) actively balance cell voltages, even advanced systems from leading brands like Tesla and BYD cannot fully eliminate this risk.
3. SOC Estimation Challenges
NCM batteries exhibit a steep voltage curve, enabling relatively accurate SOC estimation via the open-circuit voltage (OCV) method. In contrast, LFP batteries maintain a nearly flat voltage curve between 15% and 95% SOC, making OCV-based SOC readings unreliable. Without periodic full charges, LFP batteries struggle to recalibrate their SOC values. This can force the BMS into frequent protective modes, impairing functionality and long-term battery health.
Why LFP Batteries Need Weekly Full Charges
The weekly 100% charge for LFP batteries serves as a "reset" for the BMS. This process balances cell voltages and corrects SOC inaccuracies caused by their stable voltage profile. Precise SOC data is essential for the BMS to execute protective measures effectively, such as preventing over-discharge or optimizing charging cycles. Skipping this calibration may lead to premature aging or unexpected performance drops.
Best Practices for Users
- NCM Battery Owners: Prioritize partial charges (≤90%) and reserve full charges for occasional needs.
- LFP Battery Owners: Maintain daily charging below 90% but ensure a weekly full charge cycle.
- All Users: Avoid frequent deep discharges and extreme temperatures to further extend battery life.
By adopting these strategies, users can significantly enhance battery durability, reduce long-term degradation, and ensure reliable performance for electric vehicles or energy storage systems.
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Post time: Mar-13-2025
