Lithium-ion power packs have become the core energy supply component for modern electric forklifts, supporting stable material handling operations across warehouses, distribution centers and manufacturing sites. During daily high-intensity operations, unexpected current surges caused by sudden load spikes, short circuit accidents or improper operation will easily lead to irreversible damage to internal hardware of the power pack, including electrode breakage, wiring harness burnout and BMS board failure. Reasonably set over-current-protection parameters are the first line of defense to avoid such unnecessary hardware loss.

The first core parameter is peak over-current cutoff threshold, which sets the maximum instantaneous current allowed to pass through the power pack within microsecond-level duration. This parameter is usually set according to the maximum discharge capacity of internal cells and the withstand current specification of main circuit wiring. Once the instantaneous current exceeds the preset value, the protection unit will trigger fast cutoff within microseconds to avoid high temperature melting of copper bars and internal short circuit caused by instant high energy release.

The second parameter is continuous over-current limiting threshold, which targets sustained high current output that lasts from several seconds to several minutes. Different from the instantaneous peak cutoff, this parameter will not directly cut off the power supply immediately, but reduce the output power properly to keep the current within the safe range of cell heat dissipation. This setting can prevent continuous high current from triggering cumulative overheating of cell cores and circuit components, while avoiding sudden power loss that affects normal forklift operation.

The third parameter is over-current response delay time, which is calibrated to avoid misoperation caused by instantaneous current fluctuation in normal scenarios such as forklift starting and sudden climbing. A scientifically calibrated delay time can distinguish between normal operation current fluctuation and dangerous harmful over-current, to balance protection safety and operation stability.

The fourth parameter is separate calibration of charge over-current and discharge over-current thresholds. Since the internal structure and chemical characteristics of lithium cells show different tolerance for charge current and discharge current, setting two independent threshold standards can avoid hardware damage caused by excessive regenerative charging current in the process of frequent forklift braking, as well as damage caused by long-time high load discharge.

Daily regular inspection of these over-current protection parameters can help operation teams keep the power pack in a safe working state for long term, reduce unnecessary hardware replacement cost, and extend the overall service life of forklift power units.