What is the best way to store lithium batteries long term?

Alkaline and primary lithium batteries can be stored for 10 years with moderate loss capacity. When storing it, remove the battery from the equipment and place it in a dry, cool place. Batteries freeze more easily if they are kept discharged. In general, lithium-ion (Li-ion) batteries should not be stored for long periods of time, neither charged nor fully charged.

The best storage method, as determined by extensive experimentation, is to store them at a low temperature, not lower than 0 °C, between 40 and 50% of their capacity. Storage at a temperature between 5°C and 15°C is optimal. Since lithium batteries self-discharge, it is recommended to recharge them every 12 months. We can further divide it into short-term storage and long-term storage.

When checking the voltage, make sure that the battery has not been charged or discharged recently, that it is at room temperature at all times, and that it has been in a vibration-free environment. The best way to do this is to let the battery sit at room temperature for at least an hour and a half. To lose the least amount of energy while in storage, charge the battery to 40%, disconnect it and store it in a temperature-controlled place. The following graphic (the data comes from here) describes the ideal charging point and temperature for battery storage.

According to the experiment, if there is 10% to 20% of the remaining capacity of the lithium-ion polymer battery, charge it. Do not use it with main batteries (such as dry batteries) or with batteries of different capacities, models and varieties. It probably hasn't gone unnoticed that there's more than one type of lithium-ion battery available. As a general rule, it is recommended that lithium-ion or lithium-polymer battery packs be charged to between 10 and 20 percent of the remaining capacity.

Today, lithium-ion batteries are the type of battery found in nearly 99% of all laptops and devices sold in the last five years. Since their introduction in 1991, lithium-ion (Li-ion) batteries have continued to be popular among small and large businesses because of their long lifespan and lightweight designs. The following guide is based on batteries that are kept at the right temperature and humidity and in the correct state of charge. If you store it in the fridge, you can charge it to 100% and use it immediately when you need it, while if you charge it to 40% and then need the battery without having time to charge it, you are semi-screwed.

Batteries lose energy over time, so if stored uncharged, there is a chance that they won't accept a charge again. In the case of lithium-ion batteries that need to be stored for a long time and not used, they must be kept in a 50-60% state of charge. Lithium batteries require special attention, as inadequate storage can cause units to overheat and potentially catch fire in a process known as thermal leakage. When the air is too humid, condensation can build up between the terminals, which can cause a short circuit in the batteries.

Likewise, lithium-based batteries can be damaged if overcharged, causing the cathode to break down.