What is a Lithium Iron Phosphate(LiFePO4) battery?
In 1996, the University of Texas (and other contributors) discovered phosphate as cathode material for rechargeable lithium batteries. Li-phosphate offers good electrochemical performance with low resistance. This is made possible with nano-scale phosphate cathode material. The key benefits are high current rating and long cycle life, besides good thermal stability, enhanced safety and tolerance if abused.
Li-phosphate is more tolerant to full charge conditions and is less stressed than other lithium-ion systems if kept at high voltage for a pronged time. As trade-off, the lower voltage of 3.2V/cell reduces the specific energy to less than Li-manganese. In addition, cold temperature reduces performance, and elevated storage temperature shortens the service life but is still better than lead acid, NiCd or NiMH. Li-phosphate has a higher self-discharge than other Li-ion batteries, which can cause balancing issues with aging.
Figure 1: Snapshot of a typical Li-phosphate battery
Li-phosphate has excellent safety and long life span but moderate specific energy and a lower voltage than other lithium-based batteries. LFP also has higher self-discharge compared to other lithium-ion systems.
(Source: Cadex via Battery University Apr 21, 2015)