How are lithium-ion batteries made?

Strictly speaking, there are two types of Lithium Batteries: lithium metal batteries and lithium ion batteries. This is defined by t he form of lithium, lithium metal batteries use lithium metal as the electrode and lithium ion batteries exist in the form of ions in the electrode.

Lithium metal batteries generate electricity by corrosion or oxidation of the lithium metal, which is wasted and cannot be recharged, so they are also called primary batteries. Lithium-ion batteries use the difference in concentration of lithium ions to store and discharge energy, and there is no lithium metal in the battery, so it is also called a lithium secondary battery. It is currently used in mobile phones, cameras, power tools, electric vehicles, energy storage, communication base stations and other rechargeable lithium batteries. The most commonly used and visible lithium batteries on the general market are lithium-ion batteries, and we are also used to refer to them as lithium batteries, and the lithium batteries described in this article mainly refer to lithium-ion batteries.

First, Lithium Battery classification

1, the two types of classification methods used in the market: according to the pole plate material classification and according to the product appearance classification.

A, according to the pole material classification

Cathode materials: Lithium Iron Phosphate Battery (LFP), lithium cobalt oxide battery (LCO), lithium manganate battery (LMO), (binary battery: lithium nickel manganate/lithium nickel cobaltate), (ternary: lithium nickel cobalt manganate battery (NCM), lithium nickel cobalt aluminate battery (NCA))

Anode materials: lithium titanate battery (LTO), graphene battery, nanocarbon fibre battery

The graphene concept in the market mainly refers to the graphene-based battery, i.e. the graphene paste is added to the pole film or the graphene coating is added to the diaphragm. Lithium nickelate and magnesium based batteries are basically absent from the market.

B, according to product appearance classification

Divided into: cylindrical, soft bag, square.

Cylindrical and square outer packaging is mostly steel shell or aluminium shell. Soft bag packaging for aluminium-plastic film, in fact, soft bag is also a square, the market is used to aluminium-plastic film packaging called soft bag, and some people will soft bag battery called polymer battery.

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

C, according to electrolyte material

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

Liquid lithium-ion batteries use liquid electrolytes (currently most power batteries use this type). Polymer Li-ion batteries are replaced by solid polymer electrolytes, which can be "dry" or "colloidal", and most polymer gel electrolytes are currently used. Strictly speaking, solid-state batteries have solid electrodes and electrolytes.

D, according to the practical battery performance classification

Power battery and energy battery. Energy batteries are characterised by high energy density and are mainly used for high energy output; power type batteries are characterised by high power density and are 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 the battery to store high energy, can support a distance of pure electric driving, but also have good power characteristics when the low power to enter the hybrid mode.

Simple understanding, the energy type is similar to marathon runners, to have stamina, is to have high capacity, the high current discharge performance requirements are not high; Then the power type is a sprinter, fighting is the outbreak, but the stamina must also have, otherwise the capacity is too small to run far.

D, according to the practical battery performance classification

Power battery and energy battery. Energy batteries are characterised by high energy density and are mainly used for high energy output; power type batteries are characterised by high power density and are 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 the battery to store high energy, can support a distance of pure electric driving, but also have good power characteristics when the low power to enter the hybrid mode.

Simple understanding, the energy type is similar to marathon runners, to have stamina, is to have high capacity, the high current discharge performance requirements are not high; Then the power type is a sprinter, fighting is the outbreak, but the stamina must also have, otherwise the capacity is too small to run far.

Second, lithium battery material composition

Four main materials: positive electrode material, negative electrode material, diaphragm, electrolyte

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

Third, the production process

The manufacturing process of lithium battery can be divided into four main processes: electrode preparation, cell assembly, activation detection and battery assembly. Among them, the electrode production also includes the production of positive and negative electrode plates, the main links include batching, stirring, coating, rolling, cutting and pole lug and other steps.

4. Equipment needed for production

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 mixer, coating machine, roller press and scuttling machine. The coating process requires the stirred paste to be evenly coated on the metal, the thickness to be accurate to 3μm or less, and the cutting process to ensure that there is no burr on the surface of the disc, otherwise it will have a great impact on the subsequent process. Therefore, the 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, including winding machine or laminating machine, cell shell machine, liquid injection machine, and sealing and welding equipment.

The back-end equipment mainly covers the process of cell activation formation, volume separation detection and assembly into battery packs. Relatively speaking, the middle and back-end equipment, such as shell, sealing, detection and other machines, are relatively simple, and the technical requirements are not high.

Five, lithium battery application

It is mainly divided into three parts: digital class, power class, energy storage class.

Digital category: mobile phones, tablets, laptops, electric toys, MP3/MP4, headphones, charging treasure, model aircraft, mobile power supply, etc.

Power: mainly refers to electric vehicles, electric bicycles, new energy vehicles and so on.

Energy storage: mainly used in base station power supply, clean energy storage, power grid power storage, home light storage system, etc.

It is believed that lithium batteries will be more widely used in the future.