Extending the Service Life of Electric Forklift Batteries in Winter: A Systematic Technical Solution

The core causes of electric forklift battery life degradation in winter are reduced electrolyte activity, decreased charging efficiency, and sulfation (for lead-acid batteries)/lithium plating (for lithium-ion batteries) induced by low temperatures. A four-dimensional management system encompassing "charging optimization, environmental control, maintenance enhancement, and working condition adaptation" is required to balance immediate performance guarantee and long-term service life extension. Below are specific and implementable technical solutions (including quantitative standards and operational procedures):

I. Refined Management of Charging Systems (Core for Life Extension: Avoid "Undercharging/Overcharging")

(I) Adaptation and Upgrade of Charging Equipment

Selection of Low-Temperature Intelligent Chargers

Technical Requirements: Support wide-temperature charging from -20℃ to 45℃, equipped with "pre-charging activation + temperature compensation" function (charging termination voltage increases by 5~10mV per cell for every 1℃ decrease), and automatic charging current adjustment (initial low-temperature current of 0.05C, gradually increasing to 0.15C after temperature rise).Applicable Scenarios: Ordinary chargers are prone to premature power cutoff (undercharging) or overcharging (high temperature) at low temperatures. After upgrade, charging efficiency can be improved by 30%, and battery cycle life can be extended by 1.5 times.

Maintenance of Charging Interfaces and Cables

Operational Procedures: Inspect charging plugs and sockets monthly, remove oxide layers (polish with fine sandpaper), and apply conductive paste (contact resistance ≤ 0.01Ω); replace aged and cracked charging cables (cross-section ≥ 25mm², temperature resistance range from -40℃ to 125℃) to avoid heat loss during charging.

(II) Standardized Execution of Charging Processes

Control of Charging Timing and Duration

Core Principle: "Charge as you use, park fully charged". Start charging within 1 hour after daily operation, and prohibit parking overnight with insufficient power (sulfation/lithium plating speed accelerates 10 times when left standing at low temperatures with insufficient power).Quantitative Standards:

• Lead-acid batteries: Charge until voltage stabilizes for 1~2 hours (e.g., terminal voltage of 12V battery ≥ 13.8V) and current drops below 0.02C, avoiding overcharging (which causes electrolyte boiling and plate corrosion).
• Lithium-ion batteries: Charge until SOC ≥ 95% (BMS displays full charge), and unplug immediately after the charger automatically powers off. Prohibit long-term floating charge (which accelerates cell aging).

Linkage of Preheating and Charging at Low Temperatures

Operational Procedures: When ambient temperature ≤ -5℃, activate the battery preheating device (PTC heater 300-500W) before charging. Start charging only after the battery temperature rises above 5℃ to avoid intensified internal polarization caused by high-current charging at low temperatures.

II. Precise Control of Ambient Temperature (Reduce Low-Temperature Shock: Mitigate Activity Degradation)

(I) Optimization of Parking Environment

Indoor Constant-Temperature Storage

Control Standards: Maintain warehouse temperature between 5℃ and 15℃ (equipped with heating, insulation panels, or industrial air conditioning), avoiding temperatures below 0℃ (battery capacity decreases by approximately 15% and service life shortens by 20% for every 10℃ drop).Auxiliary Measures: Lay 5cm thick closed-cell foam insulation mats on the warehouse floor to prevent direct contact between the battery bottom and the cold ground (ground conduction accounts for 30% of heat dissipation).

Insulation Protection for Outdoor Parking

Mandatory Requirements: Install battery compartment insulation covers (flame-retardant V0 grade, thermal conductivity ≤ 0.03W/(m·K)) to fully cover the battery case; additionally wrap lithium-ion batteries with silicone rubber insulation layers (low-temperature resistance to -50℃) and reserve heat dissipation holes (for heat dissipation during charging).Temporary Solutions: For long-term outdoor parking, activate the preheating device once a week (30 minutes each time) to maintain battery core temperature ≥ 0℃.

(II) Preheating Activation Before Startup

Graded Preheating Strategy

• Mild low temperature (-5℃ ~ 0℃): Wrap the battery compartment with an insulation quilt and place a 100W explosion-proof heating pad (attached to the battery case) 1 hour before startup.
• Moderate low temperature (-15℃ ~ -5℃): Turn on the PTC heater (temperature controlled between 5℃ and 15℃) 2 hours before startup, and let it stand for 30 minutes after preheating before starting.
• Extreme low temperature (≤ -15℃): Adopt a combination of "preheating + supplementary charging" (after 1 hour of preheating, perform supplementary charging with 0.1C small current for 30 minutes) to improve battery activity.

Preheating Taboos

Prohibit direct heating with open flames (blowtorches, charcoal fires) to avoid electrolyte boiling and case deformation; prohibit pouring hot water on the battery (prone to seal failure).

III. Enhancement of Maintenance System (Reduce Fault Triggers: Slow Aging Rate)

(I) Specialized Maintenance for Lead-Acid Batteries (Performed Periodically)

Electrolyte Management

• Weekly inspection: Ensure electrolyte level is 10~15mm above the plates. Add distilled water if insufficient (strictly prohibit tap water or dilute sulfuric acid to avoid reducing electrolyte density).
• Biweekly testing: Measure electrolyte density (1.26~1.28g/cm³ at 25℃). If density < 1.24g/cm³, perform supplementary charging with 0.1C small current until density is restored to avoid increased freezing point and decreased activity due to insufficient density.

Plate and Case Maintenance

• Monthly cleaning: Remove oxide layers and corrosion from terminals and lugs with a copper wire brush, apply conductive paste (tightening torque ≥ 15N·m), and prevent insufficient charging caused by poor contact.
• Quarterly inspection: Check for cracks and leakage in the case. Repair or replace immediately if damaged (leakage leads to electrolyte loss and accelerated plate sulfation).

(II) Specialized Maintenance for Lithium-Ion Batteries (Core: Cell Consistency Control)

BMS System Monitoring

• Daily check: Monitor cell voltage (difference ≤ 0.2V), SOC value, and temperature (normal operating temperature 5℃~45℃) displayed by BMS. Immediately stop use and inspect if abnormal cell voltage occurs (<3.2V or >3.7V).
• Quarterly calibration: Calibrate BMS power display accuracy (error ≤ 2%) to avoid overcharging or over-discharging caused by incorrect SOC judgment.

Seal and Heat Dissipation Maintenance

• Monthly inspection: Check for aging and detachment of battery pack sealing strips (silicone rubber material) and moisture entry in shell gaps (frost, water droplets) to ensure tight sealing (prevent cell short circuit due to moisture).
• Semi-annual cleaning: Clear dust and debris from battery pack heat dissipation channels, ensure normal operation of cooling fans (automatically start when temperature >45℃), and avoid accelerated cell aging due to high temperatures.

(III) General Maintenance Checklist (Daily/Weekly/Monthly)

Maintenance Cycle	Inspection Items	Standard Requirements	Responsible Person
Daily	Battery SOC Value	Lead-acid ≥ 20%, Lithium-ion ≥ 30% (≥50% at low temperatures)	Operator
Daily	Parking Ambient Temperature	Indoor ≥ 5℃, outdoor with insulation cover	Administrator
Weekly	Terminal Cleanliness and Tightness	No oxidation, contact resistance ≤ 0.01Ω	Maintenance Technician
Weekly	Working Status of Insulation/Preheating Devices	Normal startup, temperature controlled between 5℃~15℃	Maintenance Technician
Monthly	Electrolyte Density (Lead-Acid)	1.26~1.28g/cm³ (at 25℃)	Maintenance Technician
Monthly	Lithium-Ion Battery Cell Voltage Consistency	Difference ≤ 0.2V	Maintenance Technician
Quarterly	Battery Case/Seal Integrity	No cracks, no leakage, intact sealing strips	Maintenance Technician

IV. Working Condition Adaptation and Operational Specifications (Avoid Human-Induced Damage: Reduce Load Impact)

(I) Load and Driving Control

Startup and Acceleration Specifications

Operational Procedures: After power-on, wait 3~5 seconds (BMS/controller self-inspection), then slowly press the accelerator pedal (starting current ≤ 1.5 times the rated current). Strictly prohibit forced startup by slamming the pedal (instantaneous high current causes shedding of active materials on plates and cell polarization).Low-Temperature Restrictions: Below -10℃, avoid full-load lifting and climbing (load current ≤ 80% of rated current). Perform light-load operations in multiple batches to reduce battery load.

Continuity Between Driving Range and Charging

Planning Principle: Winter driving range decreases by 30%~50%. Plan operation routes in advance to avoid mid-way power depletion (battery life degradation accelerates 5 times in low-power state); immediately return for charging if SOC drops below the safety threshold (lead-acid ≤ 20%, lithium-ion ≤ 30%) during operation.

(II) Maintenance During Long-Term Parking

Preparation Before Parking

• Power requirement: Charge lead-acid batteries to full capacity (SOC=100%) and lithium-ion batteries to 60%~80% SOC before parking for more than 3 days (avoid parking with full charge or insufficient power).
• Environmental requirement: Prioritize moving to indoor warehouses. For outdoor parking, install double-layer insulation covers and cover the battery pack surface with waterproof cloth (prevent rain and snow intrusion).

Regular Activation Process

• Every 7 days: Start the supplementary charging (charge lead-acid batteries to ≥80% SOC and lithium-ion batteries to ≥70% SOC), and idle the forklift for 5 minutes after charging to activate battery activity.
• Every 30 days: Perform small-current discharge (discharge to 50% SOC) followed by immediate full charging to avoid decreased cell consistency due to long-term standing.

V. Technical Upgrades (Long-Term Low-Temperature Scenarios: Fundamentally Improve Service Life)

(I) Battery Type Upgrade

Lead-Acid Batteries → Low-Temperature Lead-Acid Batteries

Technical Parameters: Discharge capacity ≥70% of rated capacity at -20℃, discharge rate ≥3C, plates made of high-purity lead-calcium alloy (sulfation resistance improved by 50%), service life 2~3 years longer than ordinary lead-acid batteries.

Ordinary Lithium-Ion Batteries → Low-Temperature Special Lithium-Ion Batteries

Selection Recommendations: Use ternary lithium batteries (discharge capacity ≥90% at -30℃) for environments below -20℃, and low-temperature lithium iron phosphate batteries (discharge capacity ≥80% at -20℃) for environments between -20℃ and 0℃, equipped with low-temperature BMS (supports startup at -40℃).

(II) Upgrade of Insulation and Heating Systems

Integrated Battery Pack Heating

Solution: Install flexible PTC heating films (power 200~300W) attached to the cell surface, linked with BMS (automatically start when temperature <5℃ and stop when ≥15℃) to maintain cell temperature within the optimal operating range.

Integrated Preheating and Charging

Solution: Upgrade the charging system to realize linkage of "preheating - charging - insulation". Automatically preheat the battery to above 5℃ before charging, maintain temperature ≥10℃ during charging, and keep insulation for 30 minutes after charging to avoid sudden temperature drop.

Summary: Core Logic for Service Life Extension

The key to extending battery life in winter lies in "reducing low-temperature shock, avoiding activity degradation, and eliminating human-induced damage":

• Charging End: Use low-temperature intelligent chargers to ensure "full charge without undercharging" and avoid overcharging/undercharging.
• Environmental End: Control temperature between 5℃ and 15℃, and preheat to activate at low temperatures to reduce decreased electrolyte/cell activity.
• Maintenance End: Perform regular cleaning and testing to maintain stable electrolyte/cell conditions and avoid fault triggers.
• Working Condition End: Start with light load to avoid high-current impact, and activate periodically during long-term parking.

Through the above solutions, the winter service life of lead-acid batteries can be extended by 1~2 years, and that of lithium-ion batteries by 2~3 years, while the reliability of winter operations is improved by over 90%.