This is called calendar aging, where the battery degrades as a function of time. Calendar aging is unavoidable because the degradation occurs even when there is zero battery usage. What happens when a lithium battery degrades? When a lithium battery degrades, end users will notice lower capacity and reduced power capability.
Capacity Loss: Over time, unused lithium batteries can lose their ability to hold a charge. This means that when you finally decide to use the battery, it might not last as long as it would have if it had been used regularly. The passivation layer that forms on the electrodes can contribute to this loss of capacity.
If left unused for months, a fully charged lithium battery can become completely depleted. Capacity Loss: Over time, unused lithium batteries can lose their ability to hold a charge. This means that when you finally decide to use the battery, it might not last as long as it would have if it had been used regularly.
You might be curious about how long you can store a lithium battery before it starts to degrade. Generally, lithium batteries can be stored for up to 6 to 12 months without significant degradation, provided they are stored under the right conditions.
If a lithium battery is left in a discharged state for too long, it can fall into a deep discharge state. In this state, the battery’s voltage drops too low, which can lead to irreversible damage and a significant reduction in capacity. To avoid this, always ensure that lithium batteries are stored with a partial charge. Risks of Deep Discharge
A battery that is only lightly discharged can often be recharged without any problems. However, if a battery is discharged below 2 volts per cell, it may be irreversibly damaged. It’s important to note that even if a lithium-ion battery is not being used, it will slowly self-discharge.