In today's era of energy crisis and energy revolution, secondary chemical power sources play a very important role. The development of the widely used secondary power source has gone through several stages such as lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and lithium-ion batteries (polymer lithium-ion batteries). The performance comparison of several different types of secondary batteries is shown in figure 1.

Figure 1 Comparison of performance parameters of different types of secondary batteries

It can be seen from the data in figure 1 that lead-acid batteries have mature technology, stable performance, and low prices. They still occupy a large proportion in the current market. However, lead-acid batteries have too low specific energy, short cycle life, and lead to environmental pollution. The influence of factors makes it at a disadvantage in the future secondary power competition; nickel-cadmium batteries have high specific power, long life, and strong ability to withstand deep discharge, but the metal cadmium is highly toxic. In many countries, nickel-cadmium The production of batteries has been banned, and is now gradually being replaced by metal hydride nickel batteries; MH-Ni batteries are a new type of green battery developed in the 1990s, with larger specific energy and good overcharge and overdischarge performance. And it has good interchangeability with nickel-cadmium batteries, but its single battery voltage is low, and the production cost of the battery is too high.

The concept of vanadium flow battery was proposed in 1986 when a patent filed by the University of New South Wales, Australia. It is a feature of using element vanadium to have various valence states of V5+, V4+, V3+ and V2+, and their chemical behavior is very active, which can form electric pairs of adjacent valence states. It is based on vanadium ions of different valence states in the solution. It is a type of battery with positive and negative active materials. Therefore, the positive and negative electrolytes of vanadium batteries use the same element-vanadium, which avoids the cross-contamination problem of the positive and negative electrolytes of general batteries during the charging and discharging process. Long-term operation of the battery. The battery has the advantages of simple structure, long cycle life, short response time, fast charge and discharge, and no environmental pollution. However, the all-vanadium redox flow battery has stringent requirements for the performance of ion exchange membranes, and its scale and commercialization are still developed by membranes. Troubled by bottlenecks. In addition, how to obtain key materials such as electrodes with good stability, low resistivity, good electrochemical activity, and stable electrolyte are also the main factors restricting the development of vanadium redox flow batteries. At present, the all-vanadium redox flow battery is in the research and development stage.

Development of lithium-ion batteries

Compared with the aforementioned other batteries, lithium-ion batteries have outstanding advantages such as higher specific energy and specific power. Since they were successfully developed in the early 1990s, they have become the current battery system with the best overall performance, especially polymer lithium-ion batteries. The development of technology, due to its lightness and thinness, the ability to design the battery into any shape and the advantages of good safety, has further broadened the application field of lithium-ion batteries. The production and sales of lithium-ion batteries have always maintained rapid growth. After 1994, production increased significantly.

Application of Lithium Ion Battery

In the 1990s, lithium-ion batteries tended to be widely used in various portable electronic products. With the improvement of battery design technology and the emergence of new materials, the application range of lithium-ion batteries has been continuously expanded. Civil use has expanded from information products [mobile phones, palm computers (PDAs), notebook computers, etc.] to energy transportation (electric vehicles, grid peak shaving, solar energy, wind energy storage power stations), and military applications have covered the sea (submarines, underwater robots) , Land (Army Soldier System, Robot Warrior), Sky (Unmanned Aircraft), Air (Satellite, Spacecraft), etc. Lithium-ion battery technology is no longer just an industrial technology. The development of the related information industry is one of the foundations for the development of the new energy industry, and it has become one of the important "food" indispensable for modern and future life and military equipment. .