Lithium Battery

Lithium Battery

Date:Nov 20, 2018

The abbreviation for lithium battery mainly refers to a type of battery in which lithium element is used as a main active material in an electrode material. In view of this definition, a lithium battery refers to a type of battery, including a lithium primary battery (primary battery) and a lithium secondary battery.

Lithium batteries have the advantages of being light and durable (compared to the lead storage batteries on electric vehicles), and the environmental pollution is relatively small.

A lithium battery is a type of battery in which graphite is used as a negative electrode material and a nonaqueous electrolyte solution is used. The inventor of the lithium battery is Edison.

Due to the very active chemical properties of lithium metal, the processing, storage and use of lithium metal are very demanding on the environment. Therefore, lithium batteries have not been used for a long time. With the development of microelectronics technology at the end of the twentieth century, the number of miniaturized devices has increased, and high requirements have been placed on power supplies. Lithium batteries have entered a large-scale practical stage.

It was first used in pacemakers. The self-discharge rate of the lithium battery is extremely low, and the discharge voltage is gentle. The pacemaker implanted in the body can be operated for a long time without recharging. Lithium batteries generally have a nominal voltage higher than 3.0 volts, which is more suitable as an integrated circuit power supply. Manganese dioxide batteries are widely used in computers, calculators, digital cameras, and watches.

Various materials have been studied in order to develop more excellent varieties. This creates an unprecedented product. For example, lithium sulfur dioxide batteries and lithium thionyl chloride batteries are very characteristic. Their positive active materials are also solvents for the electrolyte. This structure only occurs in electrochemical systems that are not aqueous solutions. Therefore, the research of lithium batteries has also promoted the development of electrochemical theory of non-aqueous systems. In addition to the use of various non-aqueous solvents, research on polymer thin film batteries has also been conducted.

In 1992, Sony successfully developed lithium-ion batteries. Its practicality has greatly reduced the weight and size of portable electronic devices such as mobile phones and notebook computers. The use time is greatly extended. Since lithium-ion batteries do not contain heavy metal cadmium, theoretically, some pollution is relatively reduced compared to nickel-cadmium batteries.

The lithium battery often mentioned in the 3C industry is actually a lithium-cobalt battery. The generalized chargeable lithium battery refers to a graphite anode, a cathode using cobalt, manganese or iron phosphate, and an electrolyte for transporting lithium ions. Composition. A lithium-ion battery can be used as a negative electrode in lithium metal or lithium intercalation.

The development of lithium battery industry has been concentrated in the electronic communication industry for more than 20 years, and it is mainly used in the digital industry. It is rarely used in the market of energy storage and power batteries (which require a large current in an instant). This market covers pure electric vehicles, hybrid vehicles, and medium-sized vehicles. Large UPS, solar energy, large energy storage batteries, electric hand tools, electric motorcycles, electric bicycles, aerospace equipment and aircraft batteries.

One of the main reasons is that lithium-cobalt cathode materials (LiCoO2, the most common lithium battery) used in lithium batteries cannot be used in applications requiring high current, high voltage, high torque, and resistance to puncture, impact, high temperature, low temperature, etc. Other special circumstances, and more importantly, have been criticized for failing to meet people's absolute requirements for safety.

At the same time, lithium-cobalt batteries can not achieve the purpose of fast charging and completely avoid secondary pollution. Moreover, it is necessary to design a protection circuit to prevent overcharging or over-discharging, otherwise it will cause explosion and other dangers, even if the explosion of Sony battery causes global The brand NB industry has invested heavily in recycling.

In addition, the price of cobalt is getting higher and higher, and the Congo, the world's largest producer of cobalt, has a lot of wars, which has led to an increase in the price of cobalt. The powder of lithium-cobalt battery has risen from the original price of 40 US dollars to 60-70 US dollars due to the rising price of cobalt. Lithium iron phosphate powder is priced at 30 to 60 US dollars per kilogram depending on the quality.

Over the past 20 years, countries have invested a lot of resources to find materials that can replace or solve the LiCoO2 problem and achieve some results.

The electrolyte in the lithium ion battery may be a gel, a polymer (lithium ion/lithium polymer battery), or a mixture of a gel and a polymer. Since no polymer capable of efficiently transporting lithium ions at room temperature has been found, most "plastic envelope" lithium ion/lithium polymer batteries are in fact a hybrid battery that combines a gel and a polymer.

The positive or negative electrode must have a sponge-like physical structure to release or receive lithium ions. During charging, lithium ions are removed from the negative electrode material to the electrolyte, and then enter the positive electrode material like water entering the sponge. This process is called intercalation. The process of discharging is exactly the opposite.


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