If lithium batteries are stored with their electrodes fully charged or depleted for a long time, they will suffer damage to their internal electrode structure. When fully charged, the positive electrode material is prone to releasing lithium dendrites, which may pierce the separator and cause a short circuit; in a depleted state (with less than 20% battery power), the negative electrode active material will oxidize, accelerating the loss of capacity. The correct approach is to store the battery at a charge level of 50%-60% before placing it aside. This range can prevent excessive electrode reactions and also prevent the battery from losing power due to self-discharge during storage. Taking mobile phone batteries as an example, if they are to be left idle for a long time, they can be charged to around 55% first, then turned off and stored. The subsequent performance retention rate will be more than 30% higher than when stored with full power.
In terms of temperature, extreme environments of high and low temperatures should be avoided. The ideal storage temperature is 10℃ - 25℃. High temperatures will accelerate the decomposition of the electrolyte, while low temperatures may cause an increase in internal resistance of the battery. Regarding humidity, it is necessary to stay away from humid environments such as bathrooms and basements. The battery can be placed in a sealed bag or a moisture-proof box. In case of necessity, desiccant can be used to prevent moisture from seeping into the battery and causing interface corrosion or internal component short circuits. Additionally, during storage, the battery should not come into contact with metal items (such as keys and coins) to prevent accidental short circuit due to unexpected contact of the positive and negative electrodes. Also, do not squeeze the battery to avoid damage to the shell, which may lead to leakage of the electrolyte.
Even when in an idle state, lithium batteries still have a slight self-discharge phenomenon. It is recommended to check and recharge the battery once every 3 to 6 months: First, measure the battery voltage (the normal voltage should be between 3.6V and 3.8V, corresponding to 50%-60% battery charge). If the voltage is lower than 3.5V, it is necessary to use the original charger to charge it to 50%-60% and then continue storage; at the same time, observe the appearance of the battery. If you find that the shell is bulging, deformed, or leaking, stop storing immediately and handle it properly. Do not use it again. For devices such as laptops and power banks, if the entire device is idle for a long time, it is also recommended to turn it on and check the battery status according to this cycle to avoid excessive discharge of the battery due to background power consumption of the device.
