As electric forklifts are widely adopted in modern material handling scenarios, lithium-ion batteries have become the core power source supporting daily operation. Over long-term use, operators may notice gradual reduction of available capacity, which can influence normal working schedules if no proper adjustment is made. Understanding the root causes behind such capacity degradation can help teams make targeted optimization to maximize battery utilization value.

First, improper charge and discharge operation is one of the top contributing factors. Many frontline operators may keep using the battery until its remaining power drops to extremely low level before recharging, or frequently use a high-power fast charger that exceeds the rated current limit of the battery. Long-term over-limit discharge and high-current charge will damage the stable structure of the positive electrode material, accelerate the unnecessary decomposition of internal electrolyte, and lead to irreversible loss of active lithium ions that can no longer participate in normal charge and discharge reactions.

Second, long-term exposure to unsuitable ambient temperature will significantly speed up capacity loss. If the lithium battery is continuously operated in a high temperature environment above 45 degrees Celsius, side chemical reactions inside the battery will be intensified, leading to continuous thickening of the solid electrolyte interphase layer and reduction of available reaction space. In contrast, if the battery is used for extended periods in low temperature cold storage below -10 degrees Celsius, lithium precipitation will occur on the surface of the negative electrode, which causes permanent loss of partial active lithium. Conventional test data shows that lithium batteries working in extreme temperature scenarios without corresponding protection will have 2 to 3 times faster degradation rate than those working in 15 to 30 degrees Celsius normal temperature environment.

Third, improper static storage management also leads to non-negligible capacity degradation. When electric forklifts are left idle for weeks or even months without proper processing, if the battery is kept in full charge or zero charge state for a long time, chemical potential imbalance will appear on both sides of the electrode, leading to irreversible deposition of partial active substances. Such degradation can be avoided easily by arranging regular supplementary charge to keep battery power between 40% to 60% during long term idle period.

Even if operators follow all standard operation rules completely, lithium-ion forklift batteries will still experience slow and gradual capacity reduction after hundreds of cycles. This normal aging process comes from the natural micro-loss of active materials and slow natural thickening of the interphase layer, which aligns with the conventional design life of industrial lithium batteries. Targeted daily maintenance can help extend the actual service life obviously, reducing the overall operating cost of the whole forklift fleet.