About the Storage Method of LiFePO4 Battery when It Is Not Used for a Long Time--IMPROVE BATTERY
February 13, 2023

About the Storage Method of LiFePO4 Battery when It Is Not Used for a Long Time

Lifepo4 battery is a relatively complex electrochemical system. After prolonged storage, the internal balance will gradually change. When accumulated to a certain extent, lifepo4 battery tend to undergo the following changes:

1、Physical properties.

According to the practice of lithium battery after long-term storage, the physical characteristics (appearance, size, weight, etc.) of the battery will change to a certain extent, especially the appearance characteristics. This change trend is more obvious in the storage environment with poor temperature and humidity. In the case of high humidity, the weight gain of lifepo4 battery after long-term storage is significantly higher than that of battery placed in low humidity conditions. For example, the steel casing of a battery tends to rust in high humidity conditions, resulting in a slight increase in quality. Rust will not affect the internal state of the battery, but it will directly affect the shipment of the product and may negatively affect the electronic components that match it.

2、Electrochemical properties.

Capacity. The capacity change of long-term storage lifepo4 battery is mainly reflected in two points: one is the decrease of battery capacity, mainly caused by self-discharge; the other is the increase of irreversible capacity, which mainly depends on the irreversible consumption reaction between the internal chemical systems of the battery. Self-discharge is inevitable in all lithium-ion batteries.

Internal resistance. With the increase of storage time, the internal resistance of lifepo4 battery tends to increase. Internal resistance exceeding a certain value will cause the internal battery to exceed the reference value and be scrapped or degraded. Therefore, it is necessary to pay attention to the resistance change of the battery during long-term storage.

Discharge characteristics, the discharge characteristics of lifepo4 battery show a downward trend after long-term storage. The low temperature performance of batteries stored for a long time is significantly reduced.

IMPROVE battery charge and long time storage curve
Full charge and long time storage U-I curve

How to store lifepo4 batteries when they are not used for a long time? The life of the lifepo4 battery is affected by operating temperature and ambient humidity. High temperature and high humidity will reduce battery life. For example, when the “Improve 12V100AH lifepo4 battery” is stored for a long time, it recommend that be stored at a state of charge of 40% to 60%, placed in a clean, dry and ventilated place, avoid contact with corrosive substances, and keep away from fire and heat sources. It is recommended to charge it once every three months to avoid excessive storage time. Long-term self-discharge will lead to low battery capacity and irreversible capacity loss. If the lifepo4 battery emits odor, heat, discoloration, deformation, or any abnormality during use, storage, or charging, immediately remove the battery from the device or charger and stop using it.