Lithium Iron Phosphate Batteries
Especially durable and safe
|Nominal voltage||3.3 V nominal|
|End-of-charge voltage||3.65 V|
|Energy density||90 – 120 Wh/Kg|
|Charging rate (C-rate)||Typically 0.5 – 2 C|
|Discharge rate (C-rate)||0.2 C – 5 C|
|No. of cycles||300 – 2000|
|Temperature range||-20°C ~ +60°C|
|Self-discharge||~ 3% / per month|
Lithium iron phosphate batteries are a type of lithium ion battery with a cell voltage of 3.2 V or 3.3 V. Lithium iron phosphate (LiFePO4) is used as cathode material in place of conventional lithium cobalt oxide (LiCoO2). The anode is made of graphite or hard carbon with intercalated lithium. LiFePO4 was first used in 1997 as cathode material for lithium ion batteries. It replaces the commonly used lithium cobalt cathode. The main reasons to use it as a replacement are improved environmental performance and higher reliability. The main applications of this technology include military, electric mobility, storage, and mobile devices with a focus on safety, such as in medical technology.
The charging end voltage is generally at 3.6 to 3.65 Volts, the discharge voltage is between 2.8 to 2.5 volts. The high cycle stability of this system is especially advantageous, it significantly exceeds the possible number of cycles of conventional lithium ion batteries with 1000 to 2000 cycles. Moreover, very high charge and discharge currents are possible. Unlike traditional lithium ion cells with lithium cobalt oxide (LiCoO2), no oxygen will be released in the event of an error. This can cause thermal leakage in other types of lithium-ion batteries, which can result in the burning of the cell under adverse conditions. This is less likely with lithium iron phosphate batteries. One disadvantage on the other hand is the lower voltage and lower energy density. This ultimately results in greater battery packs.