What kind of material is used for lithium batteries?

The main constituent materials of the lithium ion battery include an electrolyte, a separator, a positive and a negative material, and the like. The positive electrode material occupies a large proportion (the mass ratio of the positive and negative materials is 3:1 to 4:1), because the performance of the positive electrode material directly affects the performance of the lithium-ion battery, and the cost directly determines the battery cost.

Carbon anode material:

The negative electrode materials that have been practically used for lithium-ion batteries are basically carbon materials such as artificial graphite, natural graphite, mesocarbon microbeads, petroleum coke, carbon fiber, pyrolysis resin carbon, and the like.

Tin-based anode material:

Tin-based anode materials can be classified into tin oxides and tin-based composite oxides. Oxide refers to oxides of various valence metal tins. There are no commercial products.

Nitride

There are also no commercial products.

Alloy

Including tin-based alloys, silicon-based alloys, bismuth-based alloys, aluminum-based alloys, bismuth-based alloys, magnesium-based alloys, and other alloys, there are no commercial products.

There are two types of lithium batteries: lithium metal batteries and lithium ion batteries. This is defined in terms of the form in which lithium is made of lithium metal and the lithium-ion battery is present in the form of ions in the electrode.

Lithium metal batteries generate electricity by corrosion or oxidation of metallic lithium. When used up, they are discarded and cannot be charged. Therefore, they are also called primary batteries. Lithium-ion batteries use the difference in the concentration of lithium ions for energy storage and discharge. Metal lithium is not present in the battery, so it is also called lithium secondary battery. Currently used in mobile phones, cameras, power tools, electric vehicles, energy storage, communication base stations, and other rechargeable lithium batteries, are lithium-ion batteries. Most commonly used lithium batteries in the market are lithium-ion batteries, and everyone is used to abbreviate as lithium batteries. Lithium batteries are also mainly referred to as lithium-ion batteries.

First, lithium battery classification

1. Two classification methods used in the market: classified according to the pole piece material and classified according to the product appearance.

A, classified by pole piece material

Cathode material: lithium iron phosphate battery (LFP), lithium cobalt oxide battery (LCO), lithium manganese oxide battery (LMO), (binary battery: lithium nickel manganese oxide / lithium nickel cobaltate), (ternary: nickel cobalt manganese Lithium acid battery (NCM), nickel cobalt aluminum aluminate battery (NCA)

Anode material: lithium titanate battery (LTO), graphene battery, nano carbon fiber battery

Regarding the graphene concept on the market, it mainly refers to a graphene-based battery, that is, a graphene paste is added to a pole piece, or a graphene coating layer is added to a separator. Lithium nickelate and magnesium based batteries are basically non-existent in the market.

B, classified by product appearance

It’s divided into cylindrical, soft bag, square.

The cylindrical and square outer packaging is mostly steel or aluminum. The outer package of the soft bag is an aluminum-plastic film. In fact, the soft bag is also a square. The market is accustomed to packaging the aluminum plastic film as a soft bag, and some people refer to the soft battery as a polymer battery.

For cylindrical lithium-ion batteries, the model is typically 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 millimeters. For example, a 18650 lithium battery has a diameter of 18 mm and a height of 65 mm.

C, according to the difference of electrolyte materials

Lithium-ion batteries are classified into liquid lithium ion batteries (LIB) and polymer lithium-ion batteries (PLB).

Liquid lithium-ion batteries use liquid electrolytes (mostly current power batteries). Polymer lithium-ion batteries are replaced by solid polymer electrolytes, which can be either "dry" or "colloidal", and most currently use polymer gel electrolytes. With regard to solid state batteries, strictly speaking, both the electrodes and the electrolyte are solid.

D, classified by battery practical performance

It’s divided into power battery and energy battery. Energy-type batteries are characterized by high energy density and are mainly used for high-energy output. Power-type batteries are characterized by high power density and are mainly used for batteries with instantaneous high-power output and output. Power-energy lithium batteries have emerged with the advent of plug-in hybrid vehicles. It requires the battery to store higher energy, can support pure electric driving for a distance, and also has better power characteristics, and enters the hybrid mode when the battery is low.

Simple understanding, the energy type is similar to the marathon runners. It requires endurance, that is, it requires high capacity, and it does not require high current discharge performance. Then the power type is a sprinter, and it is a bursting force, but there is also endurance, otherwise the capacity is too Small will not run far.

Second, lithium battery material composition

Four main materials: cathode material, anode material, separator, electrolyte

Auxiliary materials: NMP, copper foil, aluminum foil, aluminum cover, conductive agent, adhesive, other (EMD), etc.

The manufacturing process of lithium batteries can be divided into four main processes: electrode production, battery assembly activation detection, and battery assembly. Among them, the electrode sheet comprises a positive electrode sheet and a negative electrode sheet, and the main steps include steps of batching, stirring, coating, rolling, slitting and tabs. According to the production process of lithium-ion batteries, lithium-ion equipment can be mainly divided into front-end equipment, mid-end equipment, and back-end equipment.

The front-end equipment is mainly for the electrode production process, including vacuum mixers, coaters, roller presses, and slitting machines. The coating process requires that the agitated slurry be evenly coated on the metal to a thickness of fewer than 3 μm. The cutting needs to ensure that there is no burr on the surface of the slice, or it will have a great impact on the subsequent process. Therefore, front-end equipment is the core equipment of battery manufacturing, which is related to the quality of the whole production line.

The mid-end equipment mainly covers the cell assembly process, and mainly includes a winding machine or a laminating machine, a cell core-in-the-shell machine, a liquid filling machine, and a sealing welding device.

The back-end equipment mainly covers cell activation, component detection, and assembly into battery packs.

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