With the development of new energy vehicles, innovations in new energy vehicle batteries are also increasing. Currently, my country is vigorously developing new energy vehicles, and national and local subsidies and license plate restrictions are making them an increasingly popular choice for car buyers. Most consumers only care about the range of electric vehicles, neglecting the core power source: the battery. Today, let's look at the types of new energy vehicle batteries, their categories, and characteristics.
I. Lithium iron phosphate batteries
During charging, some lithium ions in lithium iron phosphate are released and transferred to the negative electrode via the electrolyte, where they embed into the carbon material. Simultaneously, electrons are released from the positive electrode and travel from the external circuit to the negative electrode, maintaining the chemical reaction balance. During discharging, lithium ions are released from the negative electrode and travel to the positive electrode via the electrolyte. At the same time, electrons are released from the negative electrode and travel from the external circuit to the positive electrode, providing energy to the surrounding environment.
Features of lithium iron phosphate batteries
1. High energy density. In 2019, some excellent battery manufacturers were able to achieve an energy density of approximately 175-180Wh/kg, with a few manufacturers using stacking technology reaching an energy density of 185Wh/kg;
2. Excellent safety performance: The positive electrode material of lithium iron phosphate batteries has relatively stable electrochemical performance, which determines that it has a stable charge and discharge platform. Therefore, the battery structure will not change during charge and discharge, and it will not burn or explode. Even under special conditions such as short circuit, overcharge, compression, or puncture, it is still very safe.
3. Long cycle life: Lithium iron phosphate batteries typically have a 1C cycle life of 2000 cycles, and some even exceed 3500 cycles. The energy storage market requires 4000-5000 cycles or more, ensuring a lifespan of 8-10 years. This is higher than the 1000+ cycle life of ternary lithium batteries, while the cycle life of long-life lead-acid batteries is around 300 cycles.
4. Safe and environmentally friendly: Lithium iron phosphate batteries contain no heavy metals or rare metals, making them safe, non-toxic, and pollution-free—truly green and environmentally friendly batteries. The entire production process of lithium iron phosphate materials is clean and non-toxic, with all raw materials being non-toxic and pollution-free.
II. Ternary polymer lithium batteries
Ternary polymer lithium batteries refer to lithium batteries that use ternary cathode materials such as lithium nickel cobalt manganese oxide (Li(NicoMn)O2) or lithium nickel cobalt aluminate. Ternary composite cathode materials are made from nickel salts, cobalt salts, and manganese salts, and the ratio of nickel, cobalt, and manganese can be adjusted as necessary.
Features of ternary polymer lithium batteries
1. High energy density, with a theoretical energy density of 280 mAh/g and an actual energy density exceeding 150 mAh/g;
2. It exhibits excellent cycle performance, demonstrating superior cycle stability at both room temperature and high temperature.
3. High voltage platform, stable and reliable during cycling within the voltage range of 2.5-4.3/4.4V;
4. Long cycle life; retains over 80% of capacity after 500 cycles.
5. Ideal crystal structure, low self-discharge, and no memory effect.
III. Nickel-Metal Hydride Batteries
Nickel-metal hydride (NiMH) batteries are high-performance rechargeable batteries. They are classified into high-voltage and low-voltage types. The positive electrode active material is Ni(OH)₂ (called the NiO electrode), and the negative electrode active material is a metal hydride, also known as a hydrogen storage alloy (the electrode is called the hydrogen storage electrode). The electrolyte is a 6 mol/L potassium hydroxide solution. NiMH batteries are attracting increasing attention as an important direction for hydrogen energy applications.
Features of nickel-metal hydride batteries
1. High reliability, with good over-discharge and over-charge protection, capable of withstanding high charge-discharge rates and without dendrite formation. It exhibits excellent specific characteristics. The energy density reaches 60 mAh/g.
2. Long cycle life, up to several thousand cycles.
3. Excellent low-temperature performance; the capacity does not change significantly at -10℃.
