5 Best Practices for Storing Lithium-ion Batteries
One often underutilized aspect of storage management is lithium-ion batteries. While it may seem simple to just set a battery aside and forget about it, many common practices can lead to a shortened battery life or even dangerous consequences like fire. However, if you follow these best practices, you should be able to extend the life of your lithium-ion batteries and ensure safe handling.
1. Store lithium-ion batteries at the right temperature.
The typical lithium-ion battery storage temperature range in a home or storage unit is usually safe to store lithium batteries. The safe storage temperature range is wide, as shown in the figure below.
| Storage time | Storage temperature range |
| 1 months | -20°C to 45°C |
| 3 months | -20°C to 35°C |
| 1 year | -20°C to 25°C |
However, in extreme weather conditions, problems such as shortened battery life can occur. If you live in an area that is very cold or very hot, avoid storing lithium-ion batteries in an outdoor shed without taking proper precautions, such as using additional insulation, heating mats, or cooling units. These types of temperature fluctuations can cause the battery to expand and contract, resulting in reduced battery capacity and potential damage.
2. Take precautions for long-term storage.
Try not to store lithium batteries for too long without using them. If long storage is unavoidable, use an industrial thermometer and warning system to monitor temperature and charge. Check the battery charge level regularly to ensure that the battery is charged to the optimal level, which will help you avoid deep discharge that damages the battery.
Also, when storing the battery, make sure it is unplugged from the machine it is powering. Even if the machine is turned off, a small current will still be drawn when it is plugged in, which will drain the battery until it is fully discharged.
3. Adjust humidity.
The optimal humidity level for safe storage of lithium-ion batteries is 50%. When the humidity is too low, dew in the air can cause the battery terminals to rust, resulting in a short circuit or even a fire. To reduce humidity, use a desiccant or store the battery in its packaging.
4. Store at optimal charge.
When a lithium-ion battery is fully charged, it runs at a higher voltage, which can stress the battery and shorten its overall life. On the other hand, undercharging the battery before storage can cause deep discharge, which can cause serious damage. Lithium-ion batteries discharge more slowly when they are at the optimal partial charge, which prolongs the battery's life. Aim to keep the battery charge between 40% and 50% when storing.
5. Consider self-consumption.
When stored for long periods of time, batteries naturally discharge, known as self-consumption or self-discharge. When batteries are stored for long periods of time, they self-consume about 10-20% per year. When lithium-ion battery packs are equipped with a battery management system (BMS), additional power is required, causing the self-consumption rate to increase to about 20% per year.
Make sure to monitor this self-consumption to avoid deep discharge. Try using a State of Charge (SoC) LED monitor to track self-consumption and charge accordingly.