Related concepts and production processes of lithium ion batteries

Lithium battery concept

A lithium battery is a type of battery using a lithium metal or a lithium alloy as a negative electrode material and using a nonaqueous electrolyte solution. The first scientist to invent a lithium battery was Edison. Of course, people are now completely familiar with lithium batteries, especially after they are widely used in vehicles, electric vehicles and other transportation fields. People's attention to lithium batteries has been upgraded to a higher level.

Lithium battery classification

1. According to internal materials, lithium batteries are usually divided into two categories:

Lithium metal battery: A lithium metal battery is generally a battery using manganese dioxide as a positive electrode material, metallic lithium or an alloy metal thereof as a negative electrode material, and a nonaqueous electrolyte solution.

Lithium-ion battery: A lithium-ion battery is generally a battery using a lithium alloy metal oxide as a positive electrode material, graphite as a negative electrode material, and a non-aqueous electrolyte.

Although the lithium metal battery has a high energy density, it can theoretically reach 3,860 watts/kg. However, since it is not stable enough and cannot be charged, it cannot be used as a power battery for repeated use. Lithium-ion batteries have been developed as the main power battery due to their ability to be repeatedly charged. However, because of its combination with different elements, the composition of the cathode material varies greatly in various aspects, leading to an increase in the industry's disputes over the cathode material route.

Generally, the most commonly used power batteries are lithium iron phosphate batteries, lithium manganate batteries, lithium cobalt oxide batteries, and ternary lithium batteries (ternary nickel cobalt manganese).

2. By purpose; can also be divided into two categories:

The first one is the digital battery, which is the daily mobile phone, tablet, mobile power supply, etc. These are all digital batteries.

The second type is the power battery, which is Tesla, BYD some new energy electric vehicles, and batteries for products such as drones. These batteries require a large amount of instantaneous current, and digital batteries cannot meet the instantaneous high current, so this class is also called a high rate battery, and the price is more expensive than the digital battery.

3, according to the shell material, can be divided into three categories:

The first category, steel-shell batteries, as the name implies, is that the outer casing is steel.

The second type, the aluminum shell battery, the same shell is made of aluminum.

The third category, polymer batteries, the outer shell is a polymer material, mostly silver, a few manufacturers do black the industry becomes black leather.

4. According to the shape is also divided into three categories:

The first type, cylindrical battery, this kind of use, such as 18650, 26650, etc., this general combination, the combination of less can be used as a digital product, like the early notebook computer, generally 8 18650, mobile power, A combination of five to six, and Tesla's more than 7,000 18650 series-parallel combination.

Second, square batteries, most of which are polymer batteries, because this polymer has good ductility and can be made in many shapes. The length, width and height can be adjusted at will. Now most digital products use these batteries. .

The third type of shaped battery is some grotesque battery. According to the demand of the product, the battery should also have the matching shape. For example, the popular smart wearable products, such as the smart bracelet, are ring-shaped, so the battery is also made into a ring shape.

Lithium battery structure

The lithium battery structure is divided into five parts, namely, positive electrode, negative electrode, diaphragm, electrolyte and outer casing.

(1) The positive electrode of a lithium battery contains an active material, a conductive agent, a solvent, a binder, a matrix, and the like.

(2) The negative electrode of a lithium battery contains an active material, a binder, a solvent, a matrix, and the like.

(3) Lithium battery separator

(4) Lithium battery electrolyte

(5) The lithium battery case contains steel shells, aluminum shells, cover plates, tabs, insulating tape and other hardware.

Lithium battery production flow chart

The production process of lithium batteries is not very consistent with each manufacturer, but most of them are inseparable from these links, as shown below:

Specifically as follows: material preparation - homogenization - coating - rolling - slitting - baking - winding - shelling - laser welding - baking - injection - pre- Charging - sealing - cleaning - aging - full inspection - storage - shipping.

Lithium battery production process

Objectively speaking, the lithium battery production process is divided into three major sections, one is the production of pole pieces, the second is the production of batteries, and the third is battery assembly. In the lithium battery production process, the pole piece production is the foundation, the battery core production is the core, and the battery assembly is related to the quality of the lithium battery product. The specific steps of the lithium battery production process include positive electrode drawing, negative electrode drawing, positive electrode sheet, negative electrode sheet, steel shell assembly, liquid injection and testing, and packaging.

Introduction to lithium battery production process

As we all know, the production process of lithium battery is quite complicated. After all, the safety performance of lithium-ion battery products is directly related to the life and health of consumers. Natural lithium battery manufacturing has high requirements on the performance, accuracy stability and automation level of equipment. . Taking the preparation of the electrode slurry in the production process of the lithium battery as an example, the most front-end link of this link is also the most important part of the whole production process. After all, the influence of the electrode slurry mixing and dispersion process on the quality of the product is greater than 30. %. What is the reason?

The reason is that the preparation of the positive and negative electrodes of the lithium battery includes a series of processes such as mixing, dissolving and dispersing between liquid and liquid, liquid and solid materials, and is accompanied by changes in temperature, viscosity, environment and the like. In the positive and negative slurry, the dispersibility and uniformity of the granular active material directly affect the movement of lithium ions between the two electrodes of the battery, so the dispersion quality of the electrode slurry directly affects the product performance of the lithium battery.

It can be seen that the production process of lithium battery production process is closely related to product quality and safety. Every step of lithium battery production process must be strictly and carefully managed, so as to improve the safety performance of lithium battery products.

The page contains the contents of the machine translation.