Power battery includes lithium ion power battery, metal hydride/nickel power battery and so on. Lithium ion power battery is usually referred to as lithium ion battery, lithium ion battery is an important category of new energy vehicle power lithium battery, the market share is also the largest.
Lithium iron phosphate battery: long cycle life and more safety
Lithium ion battery with lithium iron phosphate as cathode material. It is characterized by no cobalt and other precious elements, low price of raw materials, phosphorus, iron content is very rich. LFP battery has moderate operating voltage (3.2V), large capacity per unit weight (170mAh/g), high discharge power, fast charging and long cycle life, and high stability in high temperature and heat environment.
1, high safety, high rate of charge and discharge characteristics and long cycle life. According to the literature, under the charging condition of 1C charging rate to 3.65V, then turn to constant voltage until the current drops to 0.02C, and then discharge at 1C discharging rate to the cut-off voltage 2.0V. After 1600 cycles, the battery capacity still has 80% of the initial capacity.
2, with good fast charging characteristics. Under the condition of 3C charging rate, the LFP battery can be charged 55% in 15 minutes, and its capacity can reach 95% in 30 minutes.
3. The biggest advantage of LFP battery is its good safety. LFP has stable chemical properties and good stability at high temperature. It will not decompose until 700-800℃, and it will not release oxygen molecules and will not burn violently in the face of impact, acupuncture and short circuit.
4. The disadvantage is that its performance is greatly affected by temperature. Especially in low temperature environment, discharge capacity and capacity will be greatly reduced. The energy density is low, only 120Wh/kg.
Ternary lithium ion battery: low temperature resistance and high energy density
Ternary lithium ion battery is ternary polymer lithium ion battery. The cathode material of lithium ion battery is nickel-cobalt-manganate ternary cathode material, that is, the lithium ion battery containing nickel, cobalt, manganese three elements of transition metal embedded lithium oxide conform to the cathode of the material. This material integrates the advantages of lithium cobalt, lithium nickel and lithium manganese, forming a three-phase eutectic system of three materials. Due to the ternary synergistic effect, its comprehensive performance is better than any single compound, and its weight energy density can reach 200Wh/kg.
1. The voltage platform of ternary lithium ion battery is very high. Under the same volume or weight, the specific energy and power of ternary lithium ion battery are greater. In addition, ternary lithium ion batteries have great advantages in large rate charging and low temperature resistance.
2. The safety of ternary lithium ion batteries is slightly worse. Thermal stability is poor, 250-300℃ will occur decomposition, encounter the battery in the combustible electrolyte, carbon material after a point, the heat will further aggravate the positive decomposition, in a very short time will deflagrate.Lithium-ion iron phosphate batteries do better
Compared with terpolymer lithium ion batteries, lithium iron phosphate batteries have obvious advantages in low raw material price, high safety and long service life. Many battery manufacturers are also confident in the larger market of lithium iron phosphate. Vertical technology in the performance statement said: the company's lithium iron phosphate to continue to expand production. Byd's lithium division has also publicly expressed its belief that lithium iron phosphate batteries will make a strong comeback in a local area. The analysis points out that after the real marketization, the advantages of low cost, long life and high safety of lithium iron phosphate will gradually emerge in the fields of passenger cars, commercial vehicles and special vehicles.
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