Cycle life and influencing factors of lithium iron phosphate battery
1. Lithium iron phosphate battery is used in normal temperature environment
Small current charge and discharge
In this field, if the lithium iron phosphate battery is used normally, the cycle life is basically more than 2000 times; for small lithium battery manufacturers, the quality of the lithium battery is slightly lower, and the cycle life is more than 1000 times;
High rate stable charge and discharge use
Most of the applications of high-rate discharge are power-type lithium batteries, and most of them are used in applications that provide power to motors. Because most lithium iron phosphate batteries operate under high load conditions, the decay time of battery materials is accelerated, and the cycle life is about 800 times.
High rate unstable charge and discharge use
The lithium iron phosphate battery used in this case will have a shorter lifespan, only about 300 times.
2. Lithium iron phosphate battery used in high temperature environment
The high-temperature performance of lithium iron phosphate batteries is not very mature at present. The operating temperature is -20°C to 125°C. This temperature range is the theoretical value, and the actual application temperature range is smaller.
Small current charge and discharge
In this field, if the lithium iron phosphate battery is used normally, if the battery brand manufacturer is relatively strong and the quality is good, the cycle life is basically more than 1000 times; for small lithium battery manufacturers, the quality is slightly inferior. The cycle life is more than two times; because the use of high temperature, the damage to the battery is relatively large.
High rate stable charge and discharge use
Because most lithium iron phosphate batteries operate under high load conditions, the decay time of battery materials is accelerated, and the cycle life is drastically reduced. Poor quality batteries may only have about 300 cycles; strong battery brand manufacturers, in The equipment technology and material application will be better, and the quality of the cell will be better, but the cycle life will be about 500 times.
High rate unstable charge and discharge use
Unstable operation at high temperature and discharge rate will cause greater damage to the battery and a relatively low cycle life. Tests on the cells of several battery manufacturers have found that the battery is basically unusable after 250 to 300 times.
3. Lithium iron phosphate battery used in low temperature environment
The low temperature environment has a greater impact on the performance of lithium iron phosphate batteries than high. According to the current market situation, lithium iron phosphate batteries work below -20 °C to -40 °C, and the life span is significantly reduced, and the cycle life is 300. times or so.
4. Factors affecting the cycle life of lithium iron phosphate batteries
When choosing a charger for charging and discharging, it is best to use a charger with a correct termination of the charging device to prevent the lithium iron phosphate battery from shortening its service life due to overcharging. Generally speaking, slow charging can extend the life of the battery more than fast charging. Depth of discharge The depth of discharge is the main factor affecting the life of the lithium iron phosphate battery. 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, we should avoid overdischarging lithium battery UPS to extremely low voltage. If the lithium iron phosphate battery is used at high temperature for a long time in the working environment, the electrode activity will be attenuated and the service life will be shortened. Therefore, it is a good way to prolong the life of the lithium iron phosphate battery by keeping it at a suitable operating temperature as much as possible.
Recycling of lithium iron phosphate batteries
Batteries that do not have cascade utilization value in retired lithium iron phosphate batteries and batteries after cascade utilization will eventually enter the dismantling and recycling stage. The difference between lithium iron phosphate batteries and ternary material batteries is that they do not contain heavy metals, and the recovery is mainly Li, P, and Fe. The added value of the recovered products is low, and a low-cost recovery route needs to be developed. There are mainly two recycling methods: fire method and wet method. Fire recovery process Traditional fire recovery is generally high temperature incineration of electrode sheets, burning carbon and organic matter in electrode fragments, and the remaining ash that cannot be burned is finally screened to obtain fine powder materials containing metals and metal oxides. Wet recycling process Wet recycling is mainly to dissolve the metal ions in the lithium iron phosphate battery through acid-base solution, and further use precipitation, adsorption and other methods to extract the dissolved metal ions in the form of oxides and salts. Reagents such as H2SO4, NaOH and H2O2.
