Talk About The Seven Advantages Of Lithium Iron Phosphate Batteries

    The full name of lithium iron phosphate battery is lithium iron phosphate lithium ion battery, referred to as lithium iron phosphate battery, refers to the lithium ion battery with lithium iron phosphate (LFP) as the cathode material.

       As a rechargeable battery requirements are: high capacity, high output voltage, good charge and discharge cycle performance, stable output voltage, high current charge and discharge, electrochemical stability, safety in use (not due to overcharge, over discharge and short circuit and other improper operation caused by combustion or explosion), wide operating temperature range, non-toxic or less toxic, no pollution of the environment. LiFePO4 as the positive electrode of lithium iron phosphate in these performance requirements are good, especially in the large discharge rate discharge (5 ~ 10C discharge), smooth discharge voltage, safety (no combustion, no explosion), life (number of cycles), no pollution to the environment, it is the best, is the best high-current output power battery.

Structure and working principle

    LiFePO4 is used as the positive end of the battery, which is connected to the positive end of the battery by an aluminum foil. In the middle is a polymeric diaphragm, which separates the positive end from the negative end, but the lithium ion Li can pass through but not the electron e-. On the right side is the negative end of the battery, which consists of carbon (graphite) and is connected to the negative end of the battery by a copper foil. Between the upper and lower ends of the cell is the electrolyte of the cell, which is hermetically sealed by a metal shell.

       LiFePO4 battery during charging, the lithium ion Li in the positive electrode migrates to the negative electrode through the polymer diaphragm; during discharge, the lithium ion Li in the negative electrode migrates to the positive electrode through the diaphragm. Li-ion batteries are named after the lithium ions that migrate back and forth during charging and discharging.

Main performance

       The nominal voltage of LiFePO4 battery is 3.2V, the termination charging voltage is 3.6V, and the termination discharging voltage is 2.0V. Due to the different quality and process of positive and negative electrode materials and electrolyte materials used by each manufacturer, there are some differences in its performance. For example, the same model (standard battery in the same package) has a large difference (10% to 20%) in its battery capacity.

       It should be noted here that different factories produce lithium iron phosphate batteries in the various performance parameters will have some differences; in addition, there are some battery performance is not included, such as internal resistance of the battery, self-discharge rate, charge and discharge temperature, etc..

       Lithium iron phosphate batteries have a wide range of capacity, can be divided into three categories: small zero point a few to a few mAh, medium-sized tens of mAh, large hundreds of mAh. Similar parameters of different types of batteries also have some differences.

Advantages of lithium iron phosphate batteries

1、Improvement of safety performance

       Lithium iron phosphate crystals in the P-O bond is stable, difficult to decompose, even at high temperatures or overcharge will not be like lithium cobalt acid structure collapse and heat or the formation of strong oxidizing substances, so it has a good safety.

2、Improvement of life time

       Long-life lead-acid battery cycle life of about 300 times, up to 500 times, while lithium iron phosphate batteries, cycle life of more than 2000 times, the standard charge (5-hour rate) use, can reach 2000 times. The same quality of lead-acid batteries are "new half year, old half year, maintenance and maintenance and half year", at most 1 to 1.5 years, while lithium iron phosphate batteries used under the same conditions, the theoretical life will reach 7 to 8 years. Considered together, the performance-to-price ratio is theoretically more than four times that of lead-acid batteries. High-current discharge can be high-current 2C rapid charge and discharge, in a special charger, 1.5C charging within 40 minutes can make the battery full, starting current up to 2C, while the lead-acid batteries do not have this performance.

3, high temperature performance

       Lithium iron phosphate electric heat peak up to 350 ℃ -500 ℃, while lithium manganate and lithium cobalt acid only in about 200 ℃.

4, no memory effect

       The battery is often in the full not put out of the conditions of work, the capacity will quickly fall below the rated capacity value, this phenomenon is called the memory effect. Like nickel-metal hydride, nickel-cadmium batteries have memory, while lithium iron phosphate batteries do not have this phenomenon, no matter what state the battery is in, can be used as it is charged, no need to first put out and then recharge.

5, light weight

       The same capacity of lithium iron phosphate battery volume is the volume of lead-acid batteries 2 / 3, the weight of lead-acid batteries 1 / 3.

6. environmental protection

       Lithium iron phosphate batteries are generally considered to be free of any heavy metals and rare metals (NiMH batteries require rare metals), non-toxic (SGS certification through), non-polluting, for the absolute green battery certificate.