Analysis of Key Points for Lithium Battery Pack Storage and Maintenance

During the storage of lithium battery packs, environmental conditions, battery status management and safety protection should be comprehensively considered to avoid capacity attenuation, performance deterioration and even safety accidents. The following analysis is conducted from four dimensions: storage environment, pre-storage preparation, regular maintenance, and security precautions:

First, storage environment control

Temperature management

Recommended range: The optimal storage temperature for lithium battery packs is 15℃ to 25℃. Excessively high temperatures will accelerate the internal side reactions of the battery (such as the decomposition of the electrolyte and the thickening of the SEI film), resulting in irreversible capacity attenuation. If the temperature is too low, it may increase the viscosity of the electrolyte and affect the migration efficiency of lithium ions.

Extreme temperature impact: If the storage temperature exceeds 40℃, the annual capacity attenuation rate of the battery may double. When the temperature drops below -20℃, the internal resistance of the battery increases significantly, and it is prone to overcharging or overdischarging risks when reactivated.

Humidity control

Humidity requirement: The relative humidity of the storage environment should be less than 60%. High humidity environments can easily lead to corrosion of battery casings, oxidation of interfaces, and even cause internal short circuits.

Protective measures: Dehumidification equipment can be installed in the storage area, or the battery pack can be wrapped in moisture-proof packaging (such as aluminum foil bags).

Ventilation and cleanliness

Ventilation requirements: The storage space must maintain good ventilation to prevent the accumulation of flammable gases (such as organic solvents produced by the evaporation of electrolytes).

Cleanliness: Avoid exposing the battery pack to dust and corrosive gases (such as chlorine and hydrogen sulfide) to prevent damage to the casing and electrical interfaces.

Second, preparations before storage

Power quantity control

Recommended SOC range: Before storage, the State of Charge (SOC) of the battery pack should be adjusted to 40% - 60%. This range can balance the self-discharge rate and the risk of over-discharge.

Avoid extreme SOC: Full charge (100% SOC) storage accelerates battery aging, while low charge (such as <20% SOC) storage may lead to over-discharge, causing irreversible damage.

Health status check

Key parameter detection: Before storage, the voltage, internal resistance and insulation performance of the battery pack need to be tested to ensure that there are no abnormal voltages of individual cells (such as voltage difference >50mV) or insulation failure issues.

Isolation of faulty batteries: If performance degradation or faulty modules are detected in the battery pack, they should be replaced or isolated in advance to avoid affecting overall performance.

Physical protection

Mechanical damage prevention: Battery packs should be placed on dedicated shockproof and pressure-resistant brackets or in packaging boxes to prevent internal short circuits caused by external force squeezing during storage.

Identification management: Mark the storage date, initial SOC and maintenance cycle on the battery pack casing or packaging to facilitate subsequent tracking and management.

Third, regular maintenance measures

Power compensation

Self-discharge compensation: The self-discharge rate of lithium battery packs is approximately 2% to 5% per month. It is necessary to charge the battery pack once every 3 to 6 months to restore the SOC to 40% to 60%.

Equalization charging: If the battery pack supports active equalization function, equalization can be initiated during compensation charging to reduce the capacity difference between individual batteries.

Performance recheck

Key parameter retest: Conduct a comprehensive inspection of the battery pack every 6 to 12 months, including capacity, internal resistance, insulation resistance and charge and discharge efficiency.

Data recording and analysis: Establish a battery pack storage file, record the data from previous inspections, and predict changes in battery performance through trend analysis.

Environmental adaptability inspection

Temperature and humidity calibration: Regularly inspect the temperature and humidity monitoring equipment in the storage environment to ensure the accuracy of the data.

Ventilation system maintenance: Clean the ventilation ducts and filters to prevent dust blockage and affect air circulation.

Fourth, safety precautions

Fire prevention and explosion prevention

No smoking or fire: Open flames, smoking and the use of equipment that can produce sparks are strictly prohibited in the storage area.

Fire protection equipment: Equipped with dry powder fire extinguishers, carbon dioxide fire extinguishers or heptafluoropropane fire extinguishing systems. Avoid using water-based fire extinguishers.

Prevent short circuit

Insulation treatment: The positive and negative terminals of the battery pack should be protected with insulating rubber sleeves or terminal covers to prevent contact with metal foreign objects.

Storage distance: At least 0.5 meters should be maintained between battery packs to facilitate heat dissipation and emergency handling.

Emergency response plan

Leakage handling: If electrolyte leakage is detected, protective equipment (such as acid and alkali resistant gloves and goggles) should be worn for cleaning, and the leaked substances should be adsorbed with sand or vermiculite.

Thermal runaway response: If the battery pack shows signs of thermal runaway such as smoke or fire, the power supply should be immediately cut off, the fire extinguishing system activated, and personnel evacuated.