Balancing Strategies for Reliable Vision Lithium Battery Operation

Abstract

This paper investigates frequent operational challenges associated with Vision Lithium batteries, particularly spurious alarms indicating cell overvoltage (OV) and reductions in autonomy time. Such alarms, typically registering at a warning level but occasionally escalating to faults, have been reported both during commissioning and after extended field operation. The study categorizes these issues into four main cases: (1) unbalanced cells within a module during charging near full capacity, with voltages exceeding 3.380 V per cell, (2) unbalanced cells during discharge when the state of charge (SOC) falls below 20% (under 3.150 V per cell), (3) module-level imbalances during charging, where an entire module maintains a higher voltage relative to others, and (4) single cell voltage collapse, leading to substantial reductions in backup time, with deviations reaching several minutes below expected autonomy. Tests demonstrated that using the Equalizer Tool effectively restores balance within affected modules by equalizing cell voltages when connected at approximately 2.85 V per cell for at least 8 hours. This intervention ensures balanced performance in subsequent cycles. The findings highlight the importance of proactive balancing strategies to maintain battery system reliability and operational safety.