Understanding the Importance of Charging Methods: Why EV Makers Limit Charging to 80%

Our concept for a swift charging algorithm is derived from this underlying principle. The battery cell management technique, which encompasses Charge & Battery Management Systems (BMS), is pivotal during both the charging and discharging phases of the battery's life. It's essential in averting hazards such as battery fires, explosions, capacity decline, and reduced life spans.

WaterCloud Advanced Charging Methods

Our research team has discovered that when a high-nickel-based anode material for electric vehicles was subjected to a high-speed charge and discharge cycle at 4.3 volts, the upper limit of the charging voltage, there was a notable degradation in battery performance. This issue arose from nickel atoms moving to the lithium positions during charging and failing to revert to their original positions upon discharging, causing periodic cation mixing between lithium and nickel ions.

This phenomenon was absent when the charging and discharging were performed at 4.1 volts, which is under the safety upper limit for charging voltage.

The WaterCloud Solution
  • To refine the points for clarity:
  • Implement thermal management during charge and discharge cycles to prevent dendrite formation, thermal runaway, and a decline in performance.
  • Employ an efficient charging technique to minimise the increase in heat and enhance the speed of heat dissipation.
  • Ensure the selection of cells is based on the consistency of internal resistance and thermal characteristics.
  • Maintain a specific charge and discharge C-rate.
  • Design the battery pack to align with the performance characteristics of the individual cells.
  • Utilise a real-time monitoring and control system to oversee battery status during charging and discharging processes.

Dr. Seung-Min Kim from KIST observed that utilising the full safety upper limit of the charging voltage confers no significant advantages for the constant-current-constant voltage charging method, currently adopted in many devices and applications. In fact, it may hasten the degradation of battery performance over long-term cycles.

Dr. Jang Won-young, also of KIST, highlighted the recent spate of electric vehicle fires globally. He noted that attempts to maximise the safety capacity of batteries to improve driving performance have been identified as one of the contributing factors to these incidents. Their findings emphasise the importance of the charge and discharge method's design in enabling the safe, long-distance use of batteries without a heightened fire risk.

WCD Smart AI-BMS Technology