Effects Of Over-Discharging Lithium Ion Batteries — What's At Stake?

Causes of Capacity Loss

Over-discharging lithium ion batteries can cause capacity loss due to the degradation of the battery’s internal chemistry. When a lithium ion battery is repeatedly discharged below 20% of its capacity, it can lead to the formation of crystalline structures within the battery’s cathode, which reduces its ability to hold a charge. This can result in a loss of up to 20% of the battery’s capacity after just 300 charge/discharge cycles.

Consequences of Deep Discharge

Deep discharging a lithium ion battery can have severe consequences. If a battery is discharged below 0% and then recharged, it can cause a spike in voltage and current, which can lead to a buildup of heat within the battery. This heat can cause the battery’s internal chemistry to degrade further, leading to a reduction in its overall lifespan. In extreme cases, deep discharging can even cause the battery to catch fire or explode.

Mitigating the Risks

To mitigate the risks associated with deep discharging, it’s essential to implement proper battery management practices. This includes monitoring the battery’s state of charge and avoiding discharging it below 20% of its capacity. It’s also crucial to follow the manufacturer’s recommended charge/discharge cycles and to ensure that the battery is properly maintained and stored. By taking these precautions, you can help extend the lifespan of your lithium ion batteries and prevent costly replacements.