As a leader in lithium battery technology, lithium iron phosphate (Li-FePO4) batteries are highly regarded for their excellent performance and long life. When selecting and using LiFePO4 batteries, it is crucial to understand their cycle life and the factors that affect it. In this article, we will take an in-depth look at the cycle life of LiFePO4 batteries and the various factors that affect their life.

First, let's understand what is cycle life? Cycle life is the ability of a battery to complete how many complete charge/discharge cycles while maintaining its rated capacity. In other words, it measures the rate at which a battery gradually wears out over the course of its life. Cycle life provides a more accurate and realistic assessment of life than life measured only in years.

It is important to note that the cycle life of LiFePO4 batteries and the depth of discharge (DOD) of the battery are closely related. (DOD is the depth of discharge, DoD=100% means the battery is fully discharged, DoD=80% means the battery is discharged to 80% of its rated capacity, i.e., 20% of the remaining rated capacity) Take Vantage's IFR26650-30B cell as an example:

Cycle life (100% DOD) ≥ 3000 cycles;

Cycle life (80% DOD) ≥ 6000 times;

Cycle life (50% DOD) ≥ 8000 times.

Many battery cells on the market do not label the depth of discharge when describing the cycle life, such as this type of cycle life without labeling the depth of discharge needs to be considered carefully.

Because of the excellent cycle life of Li-FePO4 battery, Li-FePO4 battery has become the first choice for many applications, such as AGV, UPS, starter batteries, medical equipment, golf carts, home storage/solar energy storage systems, etc. However, even if the same brand of the same capacity battery has the same cycle life, Li-FePO4 batteries are not labeled with the depth of discharge.

However, there are some differences in cycle life even for users of the same brand with the same battery capacity, so the factors affecting the cycle life of the battery are worthy of our attention.

Here are some of the main factors:

Type of Battery: The cycle life of a battery depends on the battery chemistry, here are the average cycle life values for batteries with different chemistries:

Lead-acid batteries: 300 cycles;

Nickel-cadmium batteries: 500 cycles;

Nickel-metal hydride batteries: 800 cycles;

Lithium-ion batteries (cobalt): 1000 cycles;

Lithium ion battery (manganese): 800 cycles;

Lithium iron phosphate battery: 2000 cycles.

Charging and discharging methods: charging and discharging methods will affect the service life of lithium iron phosphate battery. Over-charging and over-discharging may cause permanent damage to the battery, thus shortening the battery life. Therefore, it is necessary to use the charger equipped by the manufacturer to provide the correct voltage and current for the battery.

Temperature: The life of lithium iron phosphate batteries is affected by temperature. High temperatures will accelerate the aging process of the battery, resulting in shorter cycle life; too low a temperature will also affect the reaction rate of lithium iron phosphate battery. Therefore, it is crucial to use the battery within the specified operating temperature range to extend the life of lithium iron phosphate battery.

Storage conditions: Due to the nature of lithium batteries, a slight self-discharge will occur when they are not in use for a long time, so when the batteries are not in use for a long time, they should be stored at room temperature, with the charge maintained at 40-60%, and it is recommended to recharge them every 3 months to avoid the lithium iron phosphate batteries from being in a fully discharged state to ensure their health. For more specific maintenance, please follow the operating instructions and precautions for LiFePO4 batteries provided by the manufacturer.

In summary, cycle life is an important indicator to evaluate the usage time of LiFePO4 batteries. Understanding the factors that affect cycle life, such as the type of battery, charging and discharging methods, temperature and storage conditions, can help maximize the life of LiFePO4 batteries. When selecting and using LiFePO4 batteries, be sure to follow the manufacturer's guidelines for use and maintenance to ensure optimal performance and extended life.