Why LiFePO4 Batteries Cannot Be Charged Below 0°C but Can Still Discharge

The reason why LiFePO4 (Lithium Iron Phosphate) batteries, such as the EverExceed battery range, cannot be charged below 0°C yet can still discharge lies mainly in their electrochemical characteristics and safety considerations.

1. Why Charging Is Restricted at Low Temperatures

Lithium Plating Risk: At sub-zero temperatures, the insertion speed of lithium ions into the anode slows down significantly. This may lead to lithium metal plating on the anode surface, forming dendrites that could pierce the separator, causing short circuits, thermal runaway, or even fire and explosion.

Reduced Electrolyte Conductivity: Low temperatures reduce the ionic conductivity of the electrolyte, increasing internal resistance and reducing charging efficiency. This further elevates the risk of unsafe lithium deposition.

Weakened Electrode Activity: Both anode and cathode materials become less active at low temperatures. The slower diffusion of lithium ions may lead to uneven reactions during charging, potentially damaging the internal battery structure.

To prevent such risks, EverExceed lithium batteries come equipped with an advanced Battery Management System (BMS) that automatically disables charging under low-temperature conditions, ensuring long-term safety and performance.

2. Why Discharging Is Still Allowed

Discharge Reactions Are Less Aggressive: During discharge, lithium ions move from the anode to the cathode, a process that is less temperature-sensitive and poses a much lower risk compared to charging.

Energy Release, Not Storage: Discharging involves releasing energy, which does not require the same level of precision in lithium ion control as charging does, making it safer at lower temperatures.

BMS Control: EverExceed battery systems allow controlled discharge even in cold environments, thanks to intelligent BMS technology that actively monitors and protects the battery.

3. Practical Limitations in Low-Temperature Discharge

Reduced Power Output: Although discharging is possible, the increased internal resistance at low temperatures leads to lower output power and capacity.

Controlled Discharge Current: The BMS also limits discharge current under freezing conditions to prevent over-discharge and maintain battery health.

Conclusion

Charging LiFePO4 batteries, like those in the EverExceed battery solution portfolio, below 0°C is unsafe due to increased lithium plating and internal short-circuit risk. Discharging, however, is still permitted as it presents fewer dangers. Still, performance may degrade in extremely cold conditions, and proper battery management becomes essential.

For applications in harsh environments, EverExceed's reliable lithium battery solutions are designed to ensure safety, longevity, and intelligent protection—even when the temperature drops.