The impact of fast charging on battery life depends on the coupled management of three factors: rate capability (C-rate), temperature window, and state of charge (SOC) range.

I. Attenuation Mechanism (Technical Essence)

1. Lithium Plating on the Negative Electrode: When the charging speed exceeds the diffusion rate of Li⁺ intercalation into the graphite layer, metallic lithium deposits on the negative electrode surface instead of intercalating:

Irreversible capacity loss: Deposited lithium reacts with the electrolyte, consuming active lithium.

Thermal runaway risk: Lithium plating forms dendrites, which may puncture the separator (this risk requires special attention for your company's UL certification).

2. Continuous SEI Film Growth: During fast charging, the negative electrode potential is lower, and the electrolyte reduction reaction intensifies:

Each fast charging cycle increases the SEI film thickness by 0.5-2 μm,

leading to increased internal resistance (power decay) and decreased usable capacity.

3. Thermo-Mechanical Coupling Stress:

Thermal stress: Fast charging temperature rise (typically 3-5°C for LFP, up to 8-12°C for NCM) causes uneven expansion of electrode particles.

Mechanical stress: The volume change of silicon-based anodes (such as if your company develops high energy density products) can reach 300%, causing particle breakage.