Do you know the difference of polymer lithium ion battery and Lithium iron phosphate battery ?

Polymer lithium ion battery

The principle of polymer lithium ion battery is the same as that of liquid lithium, but the important difference is that the electrolyte is different from liquid lithium. The important structure of the battery includes three elements: positive electrode, negative electrode and electrolyte. Lithium iron phosphate battery has the advantages of non-toxic, non-polluting, good safety performance, wide sources of raw materials, low price, and long life. It is an ideal cathode material for a new generation of lithium-ion batteries.

Advantages of polymer lithium ion battery:

1. The working voltage of single battery is as high as 3.6v~3.8v, which is much higher than the 1.2V voltage of nickel-hydrogen and nickel-cadmium batteries;
2. Large capacity density, 1.5~2.5 times or higher than nickel-hydrogen battery or nickel-cadmium battery;
3. The self-discharge is small, and its capacity loss is also small after being placed for a long time;
4. The polymer lithium ion battery has a long life, and its cycle life can reach more than 500 times in normal use;
5. The polymer lithium ion battery has no memory effect, and it is not necessary to empty the remaining power before charging, which is convenient to use;
6. The polymer lithium ion battery has good safety performance.

Disadvantages of polymer lithium ion battery:
1. The high cost of polymer lithium ion battery makes it difficult to purify the electrolyte system;
2. To protect the circuit control, overcharging or overdischarging will destroy the reversibility of the chemical substances inside the battery, which will seriously affect the life of the battery;
lithium ion battery

Lithium iron phosphate battery


Advantages of lithium iron phosphate batteries:


1. Good high temperature performance: The thermal peak of lithium iron phosphate battery can reach 350℃-500℃, while lithium manganate and lithium cobaltate are only around 200℃. Wide operating temperature range (-20C--+75C), with high temperature resistance, lithium iron phosphate electric heating peak can reach 350℃-500℃, while lithium manganate and lithium cobaltate are only around 200℃;
2. No memory effect: The capacity of rechargeable batteries will quickly fall below the rated capacity when working under conditions that are often overflowing. This phenomenon is called memory effect. Like nickel-metal hydride and nickel-cadmium batteries, there is memory, but lithium iron phosphate batteries do not have this phenomenon. No matter what state the battery is in, it can be charged and used at any time without having to discharge it before charging;
3. Light weight: The volume of the lithium iron phosphate battery of the same specification and capacity is 2/3 of the volume of the lead-acid battery, and the weight is 1/3 of the lead-acid battery;
4. Environmental protection: The battery is generally considered to be free of any heavy metals and rare metals (the nickel-hydrogen battery requires rare metals), is non-toxic, non-polluting, conforms to European RoHS regulations, and is an absolute green battery certificate;
5. High efficiency output: standard discharge is 2~5C, continuous high current discharge can reach 10C, instant pulse discharge (10S) can reach 20C;
6. The service life of lithium-ion battery is relatively long, and the service life can reach more than 6 years. The battery with lithium iron phosphate as the positive electrode is charged and discharged with 1CDOD, and there is a record that can be used for 1000 times;
7. High energy density: Lithium iron phosphate battery has a high storage density, which has reached 460-600Wh/kg, which is about 6-7 times that of lead-acid batteries;


Disadvantages of lithium iron phosphate batteries:
1. During the sintering process during the preparation of lithium iron phosphate, iron oxide may be reduced to elemental iron in a high-temperature reducing atmosphere. Elemental iron can cause micro-short circuit of the battery, which is the most taboo substance in the battery;
2. Lithium iron phosphate batteries have some performance defects, such as low tap density and compaction density, resulting in low energy density of lithium ion batteries. The low temperature performance is poor, even if it is nanometerized and carbon coated, this problem is not solved;
3. The cost of material preparation and battery manufacturing are relatively high, the battery yield is low, and the consistency is poor;
4. Poor product consistency. At present, there is no lithium iron phosphate material factory in China that can handle this problem. From the perspective of material preparation, the synthesis reaction of lithium iron phosphate is a complex multiphase 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;
5. Lithium-ion batteries need to protect the circuit and guard against overcharge and overdischarge of the battery.



The above are the advantages and disadvantages of polymer lithium ion batteries and lithium iron phosphate batteries. Lithium ion batteries are divided into capacity type and power type. Lithium iron phosphate is basically power type, and the 1C charge-discharge cycle life can reach 2000 times. Single-cell battery will not burn or explode when overcharged at 30V. Lithium iron phosphate battery is suitable for high current discharge and is also a relatively safe battery! Which one is better depends on the use case.

 

Tip:

【3.2V】Lithium-ion ferrous phosphate batteries; 3.2 V per cell.
【3.7V】Lithium ion or lithium polymer batteries; 3.7 V per cell