Lithium battery knowledge introduction

1. Lithium battery
There are two types of lithium batteries: lithium metal batteries and lithium ion batteries. This is defined according to the form in which lithium exists. Lithium metal batteries use metal lithium as the electrode, while lithium ion batteries exist in the electrode in the form of ions.
Lithium metal batteries generate electricity through the corrosion or oxidation of metal lithium, and they are useless when they are used up and cannot be charged, so they are also called primary batteries. Lithium-ion batteries use the concentration difference of lithium ions to store and discharge energy. There is no metal lithium in the battery, so it is also called lithium secondary battery. At present, the rechargeable lithium batteries used in mobile phones, cameras, power tools, electric vehicles, energy storage, communication base stations, etc. are all lithium-ion batteries. Generally, most of the commonly used and visible lithium batteries in the market are lithium-ion batteries, and people are also accustomed to abbreviating them as lithium batteries. The lithium battery referred to in this article mainly refers to lithium-ion batteries.
1. Lithium battery classification
There are two classification methods commonly used in the market: classification by pole piece material and classification by product appearance.
A. Classified by pole piece material
Cathode materials: lithium iron phosphate battery (LFP), lithium cobalt oxide battery (LCO), lithium manganese oxide battery (LMO), (binary battery: lithium nickel manganese oxide/lithium nickel cobalt oxide), (ternary: nickel cobalt manganese lithium acid battery (NCM), lithium nickel cobalt aluminate battery (NCA))
Anode materials: Lithium titanate battery (LTO), graphene battery, nano-carbon fiber battery
B. Classification by product appearance
Divided into: cylindrical, soft bag, square.
Cylindrical and square outer packages are mostly steel shells or aluminum shells. The outer packaging of the soft pack is aluminum-plastic film. In fact, the soft pack is also a square shape. In the market, it is customary to call the aluminum-plastic film packaged soft pack, and some people call the soft pack battery a polymer battery.
For cylindrical lithium-ion batteries, the model number is generally 5 digits. The first two digits are the diameter of the battery, and the middle two digits are the height of the battery. The unit is mm. For example, the 18650 lithium battery has a diameter of 18 mm and a height of 65 mm.
C. According to different electrolyte materials
Lithium-ion batteries are divided into liquid lithium-ion batteries (LIB) and polymer lithium-ion batteries (PLB).
Liquid lithium-ion batteries use liquid electrolytes (currently most power batteries are of this type). Polymer lithium-ion batteries are replaced by solid polymer electrolytes, which can be "dry" or "colloidal". At present, most of them use polymer gel electrolytes. Regarding solid-state batteries, it strictly means that both electrodes and electrolytes are solid.
D. Classification according to battery practical performance
Power type battery and energy type battery. The energy type battery is characterized by high energy density and is mainly used for high energy output; the power type battery is characterized by high power density and is mainly used for instantaneous high power output and output batteries. The power energy type lithium battery is accompanied by the emergence of plug-in hybrid vehicles. It requires high energy stored in the battery, which can support pure electric driving for a certain distance, and also has good power characteristics, and enters the hybrid mode when the battery is low.
Simply understand, the energy type is similar to a marathon runner. To have endurance, it requires high capacity and does not have high requirements for high-current discharge performance; then the power type is a sprinter. I can't run far when I'm young.
2. Lithium battery material composition
Four main materials: positive electrode material, negative electrode material, separator, electrolyte
Auxiliary materials: NMP, copper foil, aluminum foil, aluminum shell cover, conductive agent, adhesive, other (EMD), etc.
3. Manufacturing process
The manufacturing process of lithium batteries can be divided into four main processes: electrode production, cell assembly, activation detection, and battery assembly. Among them, electrode sheet production includes positive electrode sheet and negative electrode sheet production, and the main links include steps such as batching, stirring, coating, rolling, cutting and tabbing.
4. Lithium battery application
It is mainly divided into three blocks: digital, power, and energy storage.
Digital categories: mobile phones, tablets, laptops, electric toys, MP3/MP4, earphones, charging treasures, model airplanes, mobile power supplies, etc.
Power category: mainly refers to electric vehicles, electric bicycles, new energy vehicles, etc.
Energy storage: Mainly used in base station power supply, clean energy energy storage, grid power energy storage, home optical storage system, etc.