Case Study DIY KITS
A lithium battery is a rechargeable battery that uses lithium ions to move between positive and negative electrodes to store and release electrical energy. It has the advantages of high energy density, high operating voltage, long cycle life, low self-discharge rate, no memory effect, etc., and is widely used in mobile phones, laptops, electric vehicles, energy storage systems and other fields.
First, the structure of lithium batteries
The basic structure of a lithium battery is composed of a positive electrode, a negative electrode, a diaphragm, an electrolyte and a shell.
The positive electrode generally uses metal oxides or phosphates containing lithium, such as lithium cobaltate, nickel cobalt manganese (ternary) lithium, lithium iron phosphate, etc.
The negative electrode is generally made of graphite or other carbon materials, and some use lithium metal or lithium alloy.
The diaphragm is a thin film of polymer with micropores that insulates the positive and negative electrodes, preventing short circuits while allowing lithium ions to pass through. Electrolyte is an organic solvent containing lithium salts, which is used to provide a carrier for lithium ions. The shell is a metal or plastic package used to protect the internal structure of the battery from outside interference.
Second, the working principle of lithium batteries
The working principle of lithium batteries is to achieve the process of charge and discharge through the embedding and deembedding of lithium ions between the positive and negative electrodes.
When the lithium battery is charged, the external power supply applies a positive voltage to the battery, so that the electrons flow from the positive electrode to the negative electrode, and the lithium ions are removed from the active substance of the positive electrode, through the electrolyte and the diaphragm, and embedded in the active substance of the negative electrode.
In this way, the positive electrode will produce a potential difference with the negative electrode, which is the voltage of the battery. When a lithium battery is discharged, the external circuit applies a reverse voltage to the battery, making the electrons flow from the negative terminal to the positive terminal, while the lithium ions are removed from the active substance of the negative terminal, through the electrolyte and the diaphragm, and embedded in the active substance of the positive terminal. In this way, the battery will output power to the external circuit.
Third, the performance parameters of lithium batteries
The performance parameters of lithium battery mainly include voltage, capacity, internal resistance, cycle life, discharge rate, operating temperature and so on.
Voltage refers to the potential difference of the battery, generally determined by the material of the positive and negative electrodes, and the common lithium battery voltage is 3.6V or 3.7V.
Capacity refers to the amount of electricity that the battery can give under certain discharge conditions, generally expressed in ampere-hours (Ah) or milliampere-hours (mAh), which is related to the size, materials, and process of the battery.
Internal resistance refers to the resistance when the current passes through the inside of the battery, generally expressed in ohms (Ω), and is related to the material, structure, temperature and so on.
Cycle life refers to the battery after a complete charge and discharge cycle, its capacity relative to the initial capacity of the retention rate, generally expressed as a percentage (%), and the battery material, process, charge and discharge conditions. Discharge rate refers to the size of the current when the battery is discharged, generally expressed by C, and is related to the capacity, voltage, temperature and so on.
The operating temperature refers to the environment in which the battery can maintain normal charge and discharge work and the temperature of the battery itself, generally expressed in degrees Celsius (° C), which is related to the material, structure, charge and discharge conditions of the battery.
Fourth, the classification of lithium batteries
There are a variety of classification methods for lithium batteries, and the common ones are classified according to shape, shell, cathode material, electrolyte, etc.
According to the shape, lithium batteries can be divided into cylindrical, square, flexible packaging and so on.
According to the shell, the lithium battery can be divided into steel shell, aluminum shell, plastic shell, etc. According to the positive electrode material, lithium batteries can be divided into lithium cobaltate, nickel cobalt manganese (ternary) lithium, lithium iron phosphate, etc.
According to the electrolyte, lithium batteries can be divided into liquid lithium ion batteries, polymer lithium ion batteries, all-solid lithium ion batteries and so on.
Different types of lithium batteries have their own characteristics and advantages and disadvantages, suitable for different applications.
Fifth, the application of lithium batteries
The application fields of lithium batteries are very wide, covering consumer goods, industry, special, military and other fields.
In the field of consumer goods, lithium batteries are mainly used in mobile phones, laptops, tablets, digital cameras, mobile power supplies and other electronic devices to provide portable power solutions.
In the industrial field, lithium batteries are mainly used in electric vehicles, energy storage systems, medical equipment, communication equipment, exploration and mapping and other fields to provide efficient power solutions.
In special fields, lithium batteries are mainly used in aerospace, naval ships, satellite navigation, high energy physics and other fields to provide special power solutions.
Sixth, the development prospects of lithium batteries
The development prospects of lithium batteries are very broad, with the progress of science and technology and market demand, the performance of lithium batteries will continue to improve, the cost will continue to reduce, and the application will continue to expand.
The research direction of lithium battery mainly has the following aspects: first, the development of new positive and negative electrode materials to improve the energy density and cycle life of the battery; The second is to develop new electrolytes to improve the safety and stability of the battery; The third is to develop a new battery structure to improve the charging and discharging efficiency and flexibility of the battery; The fourth is to develop a new battery management system to improve the intelligence and controllability of the battery.
The future of lithium batteries will be diversified, high performance, low-cost, intelligent direction of development, for human life and work to bring more convenience and value.
