1. Development status of lithium-ion batteries

Since their successful development in 1990, liquid lithium-ion batteries have unique advantages such as high specific energy, no pollution and high safety. They are known as the ideal green energy in the 21st century together with fuel cells and solar cells.

In addition to all the advantages of liquid lithium-ion batteries, polymer lithium-ion batteries can be made into ultra-thin batteries of any shape and size due to the use of a non-flowing electrolyte. They are more suitable for powering miniature appliances with safety features. And better. Since their industrialization in 1999, polymer lithium-ion batteries have become more widely used, gradually replacing liquid lithium-ion batteries.lithium ion battery assembly

Lithium-ion batteries are widely studied for use. For batteries used in cell phones alone, more than 80% are lithium-ion batteries. In the future, the development of large-capacity, high-efficiency lithium-ion batteries will gradually become China's electric new energy vehicles and electric bicycles ideal power supply.

2. Advantages of lithium-ion batteries

Greater than the energy. The specific energy of lithium-ion battery is as high as 460W-h/kg~600Wh/kg. therefore, the capacity of lithium-ion battery is 10 times of the same specification of lithium manganese battery.battery cell machine

Compared with Ni-Cd and Ni-MH batteries, when the capacity is the same, the quality is only half; the capacity is 20%-30% of Ni-Cd batteries and 35%-50% of Ni-MH batteries. Therefore, it is often said that lithium-ion batteries have the advantages of small size, small mass and large capacity.

High average output voltage. The rated voltage of a single cell is higher, 3.6V or 3.7V, which is 3 times of the rated voltage of NiCd and NiMH batteries, which improves the efficiency of lithium-ion batteries.prismatic cell assembly

Very low self-discharge rate. Lithium-ion batteries typically have a long-term storage life of 5 to 10 years because they self-discharge less than 10% annually when they are set aside. The self-discharge rate of a lithium-ion battery can be determined by its resistance value.

The lower the resistance value, the lower the self-discharge rate. This is because the resistance value of a Li-ion battery does not have a direct effect on its charge capacity.

No charge/discharge memory effect. Li-ion batteries do not need to be discharged before charging, and can be charged and discharged at any time without affecting the service life of the battery.

Long service life. Under normal circumstances, the lithium-ion battery charge/discharge cycle times more than 500 times, in fact, can reach more than 1200 times. Charging efficiency is up to 100%.

Allows high current operation. Lithium-ion batteries allow high-current discharging in a short period of time.

Contains no heavy metal elements such as cadmium, lead, mercury, etc. and does not pollute the environment, making it the most advanced and environmentally friendly battery of our time.

Allows a very wide range of operating ambient temperature variations, from -20°C to 60°C. It still exists in winter we can be used outdoors, but the capacity will be much lower. If it returns to room temperature, the capacity data can be recovered. This helps to improve the storage and use of lithium-ion batteries.

With perfect over-charging, over-discharging, ultra-high temperature, over-current, short-circuit protection, locking self-recovery and reliable balance charging function, which greatly extends the service life of the battery.

3. Disadvantages of lithium-ion battery

There is no interchangeability with dry batteries, and the working voltage varies greatly.

The discharge rate is large, and the capacity decreases rapidly.

Lithium-ion batteries need to be equipped with protection circuits to prevent the battery from overcharging or over-discharging.

There are safety hazards because LiPF6, the lithium salt of lithium-ion batteries, decomposes hydrofluoric acid (HF) in air, which has a strong corrosive effect on human bones, so the safety requirements are very high and must be strictly adhered to. For production and use.

Compared with other secondary batteries, production conditions are high, costly and more expensive.

Organic solvents often destroy the structure of graphite during the charging process, resulting in graphite flaking and the formation of a solid electrolyte film on its surface, leading to electrode passivation. Organic solvents also pose safety issues such as flammability and explosiveness.

Related Hot Topic

Why does the cathode in lithium ion batteries exist?

The cathode contributes significantly to the battery's voltage, to put it mildly. The anode substrate is entirely coated with active material, just like the cathode. Lithium ions released from the cathode are permitted to absorb and emit with a relatively modest rate.