Hazards and Impact Mechanisms of Undervoltage in Electric Forklift Batteries

1. Permanent Damage to the Battery Itself

(1.1) Lead-Acid Batteries

• Plate Sulfation

• In the undervoltage state, hard and non-conductive lead sulfate crystals form on the battery plates, which cannot be restored by regular charging, directly resulting in battery capacity fading. If a single undervoltage condition lasts more than 2 hours, the capacity fading rate can reach 10%-20%. After repeated undervoltage incidents, plate sulfation will gradually spread, eventually leading to battery scrapping.

• Plate Softening and Shedding

• During undervoltage discharge, the active material of the plates will soften and shed due to high-current impact. The shed material deposits at the bottom of the battery, which is likely to cause internal short circuits, leading to battery bulging and electrolyte leakage.

• Electrolyte Stratification

• Charging in the undervoltage state prevents sufficient electrolyte circulation, resulting in a stratification phenomenon where the upper layer is dilute and the lower layer is concentrated. This accelerates battery aging and reduces its service life by 30%-50%.

(1.2) Lithium Batteries

• Irreversible Cell Capacity Fading

• When the single-cell voltage drops below 2.8V, lithium elements inside the cell will precipitate and deposit on the electrode surface, piercing the separator and causing micro-short circuits, leading to permanent capacity loss of the cell. A single deep undervoltage event can cause cell capacity to fade by more than 15%, and repeated undervoltage incidents will directly result in cell scrapping.

• BMS Protection Failure

• Undervoltage leads to insufficient power supply for the Battery Management System (BMS), which makes it unable to accurately monitor single-cell voltage and temperature. Consequently, the overcharge and overcurrent protection functions are lost, and thermal runaway is likely to occur during charging, causing battery fire and explosion.

• Aggravated Single-Cell Voltage Imbalance

• In the undervoltage state, the difference in fading speed among different cells will be amplified. When the single-cell voltage difference exceeds 100mV, it cannot be repaired by regular charging, and disassembly for balancing maintenance is required, which significantly increases maintenance costs.

2. Damage to Forklift Equipment Systems

• Drive Motor and Electronic Control System Malfunctions

• Undervoltage causes unstable output current of the battery, leading to undervoltage operation of the drive motor. This results in overheating of the motor windings, accelerated aging of the insulation layer, and even motor burnout in severe cases. At the same time, insufficient voltage causes signal confusion in the electronic control system, triggering false alarms, program crashes, and even damage to the controller motherboard.

• Degraded Hydraulic System Performance

• Hydraulic pump motors rely on stable voltage supply. Undervoltage leads to insufficient motor speed, so the hydraulic system pressure fails to reach the rated value, resulting in slow lifting and tilting movements of the forklift and an increased probability of fork jamming. Long-term undervoltage operation also intensifies hydraulic pump wear, increasing maintenance costs by 20%-30%.

• Shortened Service Life of Electrical Components

• In the undervoltage state, components such as contactors and relays will frequently bounce due to insufficient pull-in voltage, causing contact ablation and oxidation, increased contact resistance, and intermittent power outages in the circuit, which affects the normal operation of the forklift.

3. Impact on Operational Safety and Efficiency

• Operational Safety Risks

• Sudden undervoltage power failure during driving will cause the forklift to lose power, which is prone to collision with surrounding equipment and goods due to inertia, resulting in property damage or casualties.Undervoltage during fork lifting may cause suspended goods to fall, leading to crushing accidents. The risk of undervoltage is higher in low-temperature environments, where battery capacity fades rapidly and the probability of sudden power failure increases by 50%.

• Significant Reduction in Operational Efficiency

• A single undervoltage incident will cause operation interruption. It takes 1-2 hours to transfer the forklift and restore power through charging, which directly affects the production rhythm.Frequent undervoltage incidents will increase the frequency of equipment downtime, reducing monthly operational efficiency by 15%-25%. Meanwhile, shortened battery service life leads to higher replacement costs, increasing the operational burden of enterprises.

4. Chain Reactions of Long-Term Undervoltage

• Sharp Increase in Battery Maintenance Costs: Frequent equalization charging, plate repair, and cell replacement are required, and the maintenance frequency is 3-5 times higher than that under normal conditions.
• Increased Equipment Failure Rate: The monthly failure frequency of motors, electronic control systems, and hydraulic systems increases by more than 20%, and the maintenance cycle is prolonged.
• Accumulation of Safety Accident Hidden Risks: Sudden failures caused by undervoltage are likely to lead to habitual unsafe operations (such as forced operation under undervoltage conditions), which further amplifies safety risks.