Advantages, disadvantages and applications of lithium iron phosphate  batteries

　　Lithium iron oxide battery refers to a lithium ion battery using lithium  iron phosphate as a positive electrode material, which has great advantages over  NI-MH and Ni-Cd batteries. The nominal voltage of the LiFePO4 battery is 3.2V,  the final charge voltage is 3.6V, and the final discharge voltage is 2.0V. Due  to the different quality and process of positive and negative electrode  materials and electrolyte materials used by various manufacturers, there will be  some differences in their performance.

　　SES Power began to use lithium iron phosphate cells to make customized  lithium batteries as early as 2009, so we are very familiar with it. Let us  explain the advantages, disadvantages, applications, etc. of lithium iron  phosphate batteries for you.

　　The advantages of lithium iron phosphate batteries

　　a: safety

　　The P-O bond in the lithium iron phosphate crystal is stable and difficult  to decompose. Even at high temperature or overcharge, it will not collapse and  generate heat like lithium cobalt oxide or form strong oxidizing substances, so  it has good safety.

　　b: life

　　The cycle life of lithium iron phosphate batteries can easily reach more  than 2,000 times, or even 8,000 times. The cycle life of a lead-acid battery  with the same energy is about 300 times

　　c: can withstand high current

　　The lithium iron phosphate battery can be discharged with high current  (generally only) and fast charge and discharge, and some special high-rate  batteries can withstand the discharge of nearly 50C.

　　d: high temperature resistance

　　The working temperature range of lithium iron phosphate battery is wide  (-20C--+75C), and the high temperature resistance of lithium iron phosphate  electric heating peak can reach 350℃-500℃, while lithium manganate and lithium  cobaltate are only around 200℃.

　　Disadvantages

　　Whether a material has application development potential, in addition to  focusing on its advantages, it is more critical whether the material has  fundamental defects.

　　a: impurities

　　During the sintering process of the lithium iron phosphate material, the  iron oxide may be reduced to elemental iron in a high-temperature reducing  atmosphere. Elemental iron can cause micro-short circuit of the battery and is  the most taboo substance in the battery. This is also the main reason why Japan  has not used this material as a positive electrode material for power  lithium-ion batteries. Of course, with the improvement of processing technology,  this problem has been fundamentally solved.

　　b: poor low temperature performance

　　The experimental results of many manufacturers show that the performance of  lithium iron phosphate batteries drops sharply at low temperatures (below -20 °  C), and it is very likely that electric vehicles cannot be driven. Although some  manufacturers claim that the lithium iron phosphate battery has a good capacity  retention rate at low temperatures, this is in the case of a small discharge  current and a low discharge cut-off voltage. SES Power's low  temperature-resistant lithium iron phosphate batteries can work at the extreme  -60 degrees Celsius and work normally at -40 degrees Celsius, which is not  something ordinary manufacturers can do.

　　c: poor consistency

　　From the perspective of material preparation, the synthesis reaction of  lithium iron phosphate is a complex heterogeneous reaction, including solid  phase phosphate, iron oxide and lithium salt, plus carbon precursor and reducing  gas phase. In this complex reaction process, it is difficult to ensure the  consistency of the reaction.

　　Application of lithium iron phosphate battery

　　Because the lithium iron phosphate battery has the above characteristics,  its main application fields are: large electric vehicles: buses, electric  vehicles, sightseeing vehicles and hybrid vehicles, etc.; light electric  vehicles: electric bicycles, golf carts, small flat-panel battery cars, shovels,  etc. Cars, cleaning cars, electric wheelchairs, etc.; electric tools: electric  drills, chainsaws, lawn mowers, etc.; remote control cars, boats, airplanes and  other toys; energy storage equipment for solar energy and wind power generation;  UPS and emergency lights, warning lights and miner’s lamps ( Safety is the  best); replace the 3V primary lithium battery and 9V nickel-cadmium or  nickel-metal hydride rechargeable battery (the same size) in the camera; small  medical equipment and portable instruments, etc.

　　SES Power adopts 12V100Ah, 24V100Ah, 36V100Ah, 48V100Ah lithium iron  phosphate battery with square aluminum shell from EVE, CATL, BYD, 3KW, 5KW home  energy storage system, rack-mounted energy storage system and other products,  which are very popular with customers. Here is an application example of  replacing lead-acid batteries with lithium iron phosphate batteries. 12V/100Ah  (1280Wh) lead-acid battery, its weight is 26kg, the number of charging times is  about 300 times, and the use time is about 2 years. If the lithium iron  phosphate power battery is used, the same 320Wh energy (4 100Ah batteries  connected in series) is used, the weight is about 9kg, the number of charging  times can reach 4000 times, and the service life can reach 5 to 8 years.  Although the price of lithium iron phosphate batteries is much higher than that  of lead-acid batteries, the overall economic effect is better to use lithium  iron phosphate batteries, and it is lighter in use.