Everything About LiFePO4 Cycle Life

By Henry, Updated on February 5, 2024

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Part 1. LiFePO4 cycle life: 3 influencing factors

The charge and discharge cycle of the LiFePO4 battery is a complex physical and chemical reaction process, and its cycle life is affected by various factors.

Charge and discharge

When choosing a battery charger, it is best to use a charger with a correct termination device to cut off the charge, to avoid shortening the service life of the lithium iron phosphate battery due to overcharging. Generally speaking, slow charging can extend the battery’s life better than fast charging.

Discharge depth

The depth of discharge is the main factor affecting the life of lithium iron phosphate batteries. The higher the depth of discharge, the shorter the life of the lithium iron phosphate battery. In other words, as long as the depth of discharge is reduced, the service life of lithium iron phosphate batteries can be greatly extended. Therefore, over-discharging lithium battery UPS to extremely low voltages should be avoided.

Working environment

If lithium iron phosphate batteries are used at high temperatures for a long time, their electrode activity will decay, and their service life will be shortened. Therefore, trying to maintain a suitable operating temperature is a good way to extend the life of lithium iron phosphate batteries.

Part 2. LiFePO4 life cycle: normal temperature environment

If a LiFePO4 battery is used normally, its cycle life is basically more than 2,000 times.

High rate stable charge and discharge

Most high-rate discharge applications are power lithium batteries, and most of them are used in applications that provide power to motors. Since most lithium iron phosphate batteries operate under high load conditions, the battery material decay time is accelerated, and the cycle life is also about 800 times.

Unstable charge and discharge at high rates

The lithium iron phosphate battery used in this case has a shorter lifespan, only about 300 times.

Part 3. LiFePO4 life cycle: high-temperature environment

The high-temperature performance of lithium iron phosphate batteries is not very mature at present, and the operating temperature is -20 °C to 125 °C. This temperature range is a theoretical value, and the actual application temperature range is smaller.

Small current charging and discharging

In this field of application, if lithium iron phosphate batteries are used normally if the battery brand manufacturer is relatively strong and of good quality, it will basically have a cycle life of more than 1,000 times; for small lithium battery manufacturers, the cycle life of slightly inferior quality will be 500 times. The cycle life is more than ten times because use at high temperatures will cause greater damage to the battery.

High rate stable charge and discharge

Since most lithium iron phosphate batteries operate under high load conditions, the battery material decay time is accelerated, and the LiFePO4 cycle life is sharply reduced. Poor-quality batteries may only last about 300 cycles; strong battery brand manufacturers. With equipment, technology, and material application, it will be better, and the battery quality will be better, but the cycle life will only be about 500 times.

Unstable charge and discharge at high rates

Unstable operation at high temperatures and discharge rates will cause greater damage to the battery and lower cycle life. Tests of cells from several battery manufacturers found that after 250 to 300 times, the battery is basically unusable.

LiFePO4 life cycle: low temperature environment

Low-temperature environments have a greater impact on the performance of lithium iron phosphate batteries than high temperatures. Judging from the current market situation, lithium iron phosphate batteries operate from below -20 °C to -40 °C, and their lifespan is significantly reduced, with a cycle life of 300 times.

Part 4. How to test LiFePO4 cycle life

The cycle and service life of lithium iron phosphate batteries can be evaluated through a series of tests. Here are some commonly used testing methods:

Charge and discharge cycle test

This is one of the key tests to evaluate battery performance and life. In this test, the battery undergoes a series of charge and discharge cycles to simulate cyclic operation under actual use conditions. Cycling testing typically involves charging to a fully charged state and then discharging to a specified end-of-discharge voltage. Repeat this charge-discharge process multiple times to evaluate the performance stability of the battery over multiple cycles.

Capacity fading test

This test measures a battery’s capacity fade, which is the change in its ability to store and release energy over time. At the beginning of the test, the battery is charged to full charge and then discharged at a rate up to the battery’s termination voltage. Repeat this process multiple times and record the actual capacity of the battery after each cycle. By comparing the initial capacity with the capacity of subsequent cycles, the capacity fading of the battery can be evaluated.

Temperature performance test

Battery performance and life are also affected by ambient temperature. Temperature performance testing typically involves exposing the battery to different temperatures and performing charge and discharge tests. This can help determine battery performance and reliability under different temperature conditions.

Internal resistance test

The internal resistance of a battery is an important factor affecting its performance and life. Internal resistance testing can evaluate the size of the battery’s internal resistance. Common testing methods include AC impedance spectrum analysis, current pulse testing, etc.

Security performance testing

The safety performance of lithium iron phosphate batteries is very important. Safety performance tests include short circuit tests, overcharge tests, over-discharge tests, etc., to evaluate the safety and stability of the battery under abnormal conditions

Part 5. FAQs

What is the lifespan of a LiFePO4 battery?

The lifespan of a LiFePO4 battery can range from 2000 to 5000 cycles, depending on factors like depth of discharge, charging methods, and operating conditions.
Can LiFePO4 batteries last 20 years?

While LiFePO4 batteries have a long lifespan, achieving 20 years would require favorable usage patterns, proper maintenance, and optimal operating conditions.
How many cycles does a LiFePO4 have?

LiFePO4 batteries typically have a cycle life ranging from 2000 to 5000 cycles, depending on factors such as depth of discharge, charging protocols, and environmental conditions.
Is LiFePO4 better than lithium-ion cycle life?

LiFePO4 batteries generally offer better cycle life than traditional lithium-ion batteries due to their more stable chemistry and robust construction.
Does LiFePO4 Battery Cycle Life Matter?

Yes, the cycle life of a LiFePO4 battery is an important consideration as it determines the number of charge and discharge cycles it can undergo before experiencing significant capacity loss.