Lithium Iron Phosphate

Lithium iron phosphate (LiFePO4) will be the preferred technique battery for the propulsion of vehicles and other applications where high currents and a long lifetime will be of interest. Iron Phosphate lithium batteries are based on the original composition of lithium-ion, LiFePO4, however, is the cathode used in place of lithium cobalt dioxide (LiCoO2). These can be found in most laptops, cell phones, MP3 players etc.

LiFePO4 is an inherently safe material to use as cathode because exothermic reaction does not occur as in LiCoO2 can happen: LiFePO4 battery cell can ignite or explode, not even in extreme conditions. LiFePO4 cells are able to handle high discharge, they contain no toxic substances and have a very long life. These different properties have led to popularity inter alia electric vehicles (see also ‘Application’).

LiFePO4 makes the ideal chemistry for electric vehicle applications as can be seen in the table below. In almost 90% of all traction applications lead acid is still used as this is a proven technology and has a favorable price per unit. However, capacity, weight, operating temperatures and a low CO2 footprint are advantages of LiFePO4. Although the initial purchase price of LiFePO4 is higher than lead acid, the longer cycle life makes it a financially sound choice.

LITHIUM CHARACTERESTICS

Battery type

M2POWER
LIFEPO4
(Lithium battery)

LiMn2O4

LiCoO2

PbA
(lead acid

battery)

Energy storage Good Good Very good Bad
Cyclelife 1000-2000 300-800 300-500 200-300
Total Cost
of Ownership
Very good Acceptable Acceptable Acceptable
Safety Good Unsafe duringhigh discharge Unsafe duringhigh discharge Good
Size Good Good Very good Bad
Weight Good Good Very good Bad
Operating temperature Good -45 grC
to 70 grC
Bad  > 50 grC  Bad  < -20 grC >
50 grC Good
Bad < 0 grC