What Causes a Decline in LiFePO4 Battery Capacity?

The decline of the LiFePO4 battery capacity is a natural occurrence. Whatever type of battery you use, there will inevitably be a decrease in capacity after a long period of use. This is determined by the nature of the battery itself. But what causes a decline in LiFePO4 battery capacity?

Why Does The Capacity of LiFePO4 Batteries Decrease?

The Cathode Material's Structure Changes

The cathode material is an important component of lithium iron phosphate batteries. When lithium ions are removed from the cathode, the metal elements are inevitably oxidized in order to maintain the electrical neutrality of the material, accompanied by a change in composition. The end result is mechanical damage to the cathode material structure, resulting in a decrease in electrochemical performance, i.e., a decrease in the capacity of the lithium iron phosphate battery.

The Anode Material's Structure Changes

Graphite is a common anode material for LiFePO4 batteries. SEI is formed on the surface of the negative electrode during the electrochemical reaction, which consumes part of the lithium ions. The capacity of the battery will gradually decrease over time due to the change in the graphite structure.

Battery Overcharge

When a battery is overcharged, electrochemically inert substances like Co3O4 and Mn2O3 are produced. The presence o these substances disrupts the capacity balance between the electrodes. As a consequence, the capacity of the LiFePO4 battery decreases, and this reaction cannot be reversed.

The LiFePO4 battery capacity decline is actually caused by a number of factors, not just those we've already mentioned. The LiFePO4 battery is a whole, and if any of the substances inside it change, the capacity will change as well.

How to Prevent LiFePO4 Battery Capacity Decrease?

We should use LiFePO4 batteries in accordance with regulations and avoid overcharging and overdischarging, which will result in irreversible, massive battery losses.

Furthermore, the battery terminals of the LiFePO4 battery should be checked on a regular basis. If oxidation occurs, it should be cleaned as soon as possible to avoid affecting the battery's power output. Oxidation will also raise the battery's operating temperature, resulting in a reduction in capacity.

Conclusion

Although the decrease in LiFePO4 battery capacity cannot be completely avoided, it is possible to delay this process by either taking good care of the batteries or purchasing LiFePO4 battery products from reputable manufacturers who will provide expert assistance.