What are lithium-ion batteries？
Lithium-ion battery is a kind of secondary battery (rechargeable battery), which mainly relies on the movement of lithium ions between the cathode and anode to work. During charging and discharging, Li+ goes back and forth between the two electrodes for embedding and de-embedding: during charging, Li+ is de-embedded from the cathode and passes through the electrolyte to be embedded in the anode, which is in a lithium-rich state; and the opposite is true during discharging.
On October 9, 2019, the Royal Swedish Academy of Sciences announced that it had awarded the 2019 Nobel Prize in Chemistry to John Bannister Goodenough, Stanley Whittingham, and Akira Yoshino for their contributions to the field of lithium-ion battery research and development.
Lithium-ion batteries are composed of the following key components:
1. Cathode: usually made from a lithium-containing compound coated on a metal aluminum foil. Common cathode materials include lithium manganese oxide, lithium cobalt oxide, NCM materials (e.g., lithium nickel-cobalt manganate) and LFP(lithium iron phosphate). The main function of anode materials is to store and release lithium ions.
2. Anode: usually made of carbon materials such as graphite or non-carbon materials coated on metal copper foil. Anode material is the main body of lithium battery to store lithium, so that lithium ions are embedded and dislodged in the charging and discharging process.
3. Separator: It is a special composite film, the main function is to prevent direct contact between positive and negative electrodes to prevent short circuit.
4. Electrolyte: the main function is to provide a transport medium for lithium ions.
5. Shell: used for battery encapsulation, to protect the internal structure of the battery.
The main classification of lithium-ion batteries:
1. According to the different electrolyte materials used in lithium batteries, lithium batteries can be divided into two categories: liquid lithium batteries and polymer lithium batteries;
2. Lithium batteries according to appearance: there are prismatic lithium batteries (such as commonly used cell phone batteries) and cylindrical (such as 18650, 18500), pouch lithium batteries, shaped lithium batteries (such as for wearable devices and other special electronic products);
3. Lithium batteries according to the outer packaging material: aluminum can lithium batteries, steel can lithium batteries, soft pack batteries;
4. lithium battery according to the battery cathode and anode material classification can be divided into:
4.1 NCM lithium batteries, NCM lithium batteries are widely used in power tools, electric bicycles, scooters and some electric vehicles in the power system;
4.2 LFP Lithium batteries, using LiFePO4 material as the cathode material, with lower manufacturing cost and high safety, are considered one of the safest batteries. LFP batteries are mainly used in standard or short-range electric vehicles and energy storage systems, with long life and good thermal stability;
4.3 Lithium cobalt oxide batteries are widely used in portable electronic devices, such as cell phones, laptops and tablet PCs, and can provide high operating voltage and specific capacity to meet the demand for thin and light weight and long endurance of these devices;
4.4 Lithium manganese oxide battery is widely used in power tools, electric bicycles and certain digital electronic products due to its relatively low price, high voltage platform, good multiplier performance and high safety performance.