1. The working principle of lithium-ion battery As we all know, the positive electrode material of a lithium ion battery is lithium cobalt oxide, and the negative electrode is carbon. The working principle of lithium-ion battery refers to its charging and discharging principle. When the battery is charged, lithium ions are generated on the positive electrode of the battery, and the generated lithium ions move to the negative electrode through the electrolyte. The carbon as the negative electrode has a layered structure, and it has many micropores. The lithium ions reaching the negative electrode are embedded in the micropores of the carbon layer, and the more lithium ions are embedded, the higher the charging capacity.
By the same token, when the battery is discharged (ie, the process we use the battery), the lithium ions embedded in the carbon layer of the negative electrode come out and move back to the positive electrode. The more lithium ions return to the positive electrode, the higher the discharge capacity. What we usually call battery capacity refers to the discharge capacity.
It is not difficult to see that during the charging and discharging process of a lithium ion battery, the lithium ion is in a state of motion from the positive electrode to the negative electrode to the positive electrode. If we compare the lithium-ion battery to a rocking chair, the two ends of the rocking chair are the two poles of the battery, and the lithium ion is like an excellent sportsman, running back and forth at both ends of the rocking chair. Therefore, the experts gave the lithium-ion battery a cute name rocking chair battery.

2. Assembly process of lithium ion battery
The process technology of lithium-ion batteries is very strict and complicated. Here are just a few of the main processes.
2.1 Pulping: Mixing with a powdery positive and negative active material with a special solvent and a binder, and stirring it at a high speed to form a slurry of positive and negative materials.
2.2 Coating film: The prepared slurry was uniformly coated on the surface of the metal foil, and dried to prepare positive and negative electrode pieces, respectively.
2.3 Assembling: According to the positive electrode sheet--separator--negative electrode sheet--the diaphragm is placed in the order from top to bottom, and the battery core is wound up, and then the electrolyte is injected into the sealing process to complete the assembly of the battery. Process to make a finished battery.
2.4 Chemicalization: Charge and discharge the finished battery with a dedicated battery charge and discharge device, test each battery, and screen out the qualified finished battery, waiting for delivery.

3. Safety characteristics of lithium ion batteries
Lithium-ion batteries have been widely used in people's daily lives, so its safety performance should definitely be the first indicator of lithium-ion batteries. For the safety performance evaluation indicators of lithium-ion batteries, very strict standards have been set internationally. A qualified lithium-ion battery should meet the following conditions in terms of safety performance.
3.1 Short circuit: no fire, no explosion
3.2 Overcharge: no fire, no explosion
3.3 Hot box test: no fire, no explosion (150 °C constant temperature 10min)
3.4 Acupuncture: Do not explode (use Ф3mm nail to penetrate the battery)
3.5 Plate impact: no fire, no explosion (10kg weight from 1M high to battery)
3.6 Incineration: No explosion (gas flame barbecue battery)
 
4. How is the safety characteristics of lithium-ion batteries realized?
In order to ensure the safety of lithium-ion batteries, experts have carried out a very strict and thorough battery safety design to achieve battery safety assessment indicators.
4.1 Diaphragm 135 °C automatic shutdown protection: the international advanced Celgard2300PE-PP-PE three-layer composite film. When the battery temperature rises to 120 °C, the PE film holes on both sides of the composite film are closed, the internal resistance of the battery increases, and the internal temperature rise of the battery is slowed down. When the battery temperature rises to 135 °C, the PP film hole is closed, the battery internal circuit is broken, and the battery is no longer used. Warm up to ensure battery safety*.
4.2 Adding additives to the electro-hydraulic: When the battery is overcharged and the battery voltage is higher than 4.2v, the electro-hydraulic additive is polymerized with other substances in the electro-hydraulic, the internal resistance of the battery is increased, and the battery is internally broken to form a large area, and the battery is not Warm up again.
4.3 Battery cover composite structure: The battery cover adopts the scoring explosion-proof structure. When the battery is warmed up, part of the gas generated during the activation process of the battery expands, the internal pressure of the battery increases, and the pressure reaches a certain degree of cracking and deflation.
4.4 Various environmental abuse tests: Conduct various abuse tests, such as external short circuit, overcharge, acupuncture, plate impact, incineration, etc., to examine the safety performance of the battery. At the same time, the battery is subjected to temperature shock test and mechanical tests such as vibration, drop and impact, and the performance of the battery under actual use environment is investigated.
 
5. Lithium-ion battery is a new type of green battery
"Caring for the environment and protecting the earth" is our unshirkable responsibility. How to reflect our environmental philosophy in action?
As a battery consumer, you should buy and use new green batteries; as a battery manufacturer, you should produce new green batteries. Only through the joint efforts of all can we create and protect our beautiful and harmonious natural environment.
The new green battery refers to a class of high-performance, pollution-free batteries that have been put into use or are being developed in recent years. Lithium-ion batteries, metal hydride nickel batteries, and mercury-free alkaline zinc-manganese batteries that are currently being widely used, and lithium or lithium ion plastic batteries, fuel cells, and electrochemical energy storage supercapacitors that are being developed are all new types. The scope of green batteries. In addition, solar cells (also known as photovoltaic power generation) that use solar energy for photoelectric conversion, which are widely used at present, belong to this category.