Lithium iron phosphate (LFP) batteries are a type of lithium-ion rechargeable battery, primarily used in power batteries, and offer significant advantages over Ni-MH and Ni-Cd batteries. LFP batteries have high charge/discharge efficiency, reaching over 90% under high-rate discharge conditions, while lead-acid batteries achieve approximately 80%. Below is a brief overview of the seven major advantages of LFP batteries.
I. Improved safety performance
The PO bonds in lithium iron phosphate crystals are stable and difficult to decompose. Even at high temperatures or under overcharge, they do not collapse and generate heat or form strong oxidizing substances like lithium cobalt oxide, thus exhibiting good safety. Reports indicate that in actual operation, a small number of samples showed combustion in nail penetration or short-circuit tests, but no explosions were observed. However, in overcharge tests using voltages several times higher than their discharge voltage, explosions were still observed. Nevertheless, its overcharge safety is significantly improved compared to ordinary liquid electrolyte lithium cobalt oxide batteries.
II. Improved lifespan
Lithium iron phosphate batteries are lithium-ion batteries that use lithium iron phosphate as the positive electrode material.
Long-life lead-acid batteries have a cycle life of around 300 cycles, with a maximum of 500 cycles. Lithium iron phosphate (LFP) batteries, on the other hand, have a cycle life exceeding 2000 cycles, reaching 2000 cycles under standard charging (5-hour rate). Lead-acid batteries of the same quality typically last only 1-1.5 years – "new for six months, old for six months, and then another six months of maintenance" – while LFP batteries, under the same conditions, theoretically have a lifespan of 7-8 years. Considering all factors, the performance-price ratio is theoretically more than four times that of lead-acid batteries. LFP batteries also offer high-current discharge and fast charging/discharging capabilities, allowing for 2C fast charging and discharging. With a dedicated charger, a 1.5C charge can fully charge the battery within 40 minutes, and the starting current can reach 2C – capabilities not found in lead-acid batteries.
III. Good high-temperature performance
Lithium iron phosphate (LFP) has a peak thermal conductivity of 350℃-500℃, while lithium manganese oxide and lithium cobalt oxide are only around 200℃. It has a wide operating temperature range (-20℃ to +75℃) and high-temperature resistance.
IV. Large Capacity
It has a larger capacity than ordinary batteries (such as lead-acid batteries). The capacity of a single cell ranges from 5AH to 1000AH.
V. Memoryless effect
When rechargeable batteries are frequently left fully charged without being completely discharged, their capacity will rapidly drop below the rated value; this phenomenon is called the memory effect. Nickel-metal hydride and nickel-cadmium batteries exhibit this memory effect, while lithium iron phosphate batteries do not. These batteries can be charged and used immediately regardless of their state, without needing to be fully discharged before recharging.
VI. Lightweight
A lithium iron phosphate battery of the same capacity is 2/3 the volume of a lead-acid battery and 1/3 the weight of a lead-acid battery.
VII. Environmental Protection
Lithium iron phosphate batteries are generally considered to be free of any heavy metals and rare metals (nickel-metal hydride batteries require rare metals), non-toxic (SGS certified), pollution-free, and compliant with European RoHS regulations, making them absolutely green and environmentally friendly batteries. Therefore, the main reason lithium batteries are favored by the industry is their environmental benefits. Consequently, this type of battery was included in the "863" National High-Tech Development Program during the "15th Five-Year Plan" period, becoming a key project supported and encouraged by the state.
Of course, lithium iron phosphate batteries also have disadvantages, such as poor low-temperature performance, low tap density of the cathode material, and a larger volume for lithium iron phosphate batteries of the same capacity compared to lithium-ion batteries such as lithium cobalt oxide. Therefore, they are not advantageous in the field of micro-batteries. When used in power batteries, lithium iron phosphate batteries, like other batteries, need to address the issue of battery consistency.
