Without balancing, when one cell in a pack reaches its upper voltage limit during charging, the monitoring circuit signals the control system to stop charging, leaving the pack undercharged.
How to balance a battery pack correctly?
needs two key things to balance a battery pack correctly: balancing circuitry and balancing algorithms. While a few methods exist to implement balancing circuitry, they all rely on balancing algorithms to know which cells to balance and when. So far, we have been assuming that the BMS knows the SoC and the amount of energy in each series cell.
Without balancing, when one cell in a pack reaches its upper voltage limit during charging, the monitoring circuit signals the control system to stop charging, leaving the pack undercharged. With balancing, the Battery Management System (BMS) continuously monitors voltage differences and upper voltage limits.
What is battery cell balancing?
Battery cell balancing brings an out-of-balance battery pack back into balance and actively works to keep it balanced. Cell balancing allows for all the energy in a battery pack to be used and reduces the wear and degradation on the battery pack, maximizing battery lifespan. How long does it take to balance cells?
For battery systems that do not come with an integrated balancing feature, consider investing in a balance board or a dedicated charger that can help maintain consistent cell voltages over time. These systems actively balance the cells during charging, preventing discrepancies from growing too large.
From a State of Charge (SOC) perspective, without balancing, the SOC range is typically limited to 20% to 80% for safety reasons, providing only 60% usable capacity. With balancing, the SOC range can be expanded from 5% to 95%, increasing usable capacity to 90%. This means the battery pack's usable capacity is significantly enhanced.
What does unbalanced battery pack mean?
This unbalanced pack means that every cycle delivers 10% less than the nameplate capacity, locking away the capacity you paid for and increasing degradation on every cell. The solution is battery balancing, or moving energy between cells to level them at the same SoC.