How to store lithium-ion batteries is extremely important from both a safety and efficiency perspective. Therefore, to protect batteries from overheating and lead to a sensation known as thermal runaway, we should pay more attention to the way that your batteries are stored in the short or long term.
To ensure you store your lithium-ion batteries safely and correctly, we explain more details from the aspects as below:
Temperature
The optimal storage temperature for lithium-ion batteries is 15°C (59°F). The higher the storage temperature of your lithium-ion battery, the faster it will self-discharge, but this is not always the case . Therefore, please thoroughly read the labels for proper storage of specific battery types before storing lithium batteries.
In most cases, temperatures below freezing will not seriously damage lithium-ion batteries because they do not contain water. However, in no case should you store them at temperatures below freezing. If you want to store lithium-ion batteries for a long period of time, make sure the best conditions are available.
Humidity
The optimum storage humidity for lithium-ion batteries is 50%. When the air is too humid, condensation can build up between the terminals, which can cause the battery to short-circuit.
In the worst case scenario, a short circuit can cause the battery to overheat and possibly even catch fire, as you should provide a separate cover for each terminal and do everything possible to prevent moisture from damaging the lithium-ion battery.
Charge
Every battery self-discharges when it is stored in the long term. Typically, most lithium-ion batteries will self-discharge at around 5% in the first 24 hours of being charged. Thereafter, each battery will discharge at a rate of 1-2% per month. If your lithium-ion battery comes with a safety circuit, this alone will contribute to a self-discharge rate of around 3%.
It’s best to store your lithium-ion batteries at around a 40-50% state of charge if you plan to use them immediately. You should also be mindful that lithium-ion batteries can suffer damage if you overcharge them for too long.
Trickle, Fast, and Constant Charge
When you check the charge of a lithium-ion battery, you need to remove it from storage and leave it at room temperature for a few hours. Then you can test it. If you find that your lithium-ion battery appears heavily discharged, you will need to do the following:
Trickle charge: (0.1C) until the cell voltage reaches 2.8 volts. If you don’t see this occur within an hour, your battery is probably damaged beyond repair.
Fast charge: (1C) until the cell voltage reaches 4.2 volts. This should occur within 2 hours.
Constant charge: until the charge current drops below 0.07C.
Maintenance and Handling Precautions
- Monitor battery charge status while charging
- Ensure temperature controls are set to specified temperatures
- Observe run time with a fully-charged battery
- Lithium Ion Batteries Stored on Shelves
- If you drop a battery, inspect closely for damage and isolate that battery if possible until fully test
- Check batteries before placing them in storage for irregularities in charge status
- Avoid exposing Li-Ion batteries to excessive vibration
- Do not keep batteries in excessively high OR low temperatures
- Always handle batteries with caution
- Place batteries in storage after the building reaches recommended temperature levels
- Do not use damaged batteries
- In case of contact with fluid, do not rub your eyes. Immediately flush eyes at an eyewash station
- Wash hands after handling batteries