The structure of lifepo4 battery
Power lithium batteries are usually composed of positive electrodes, negative electrodes, electrolytes, separators, conductive agents, and binder materials.
The lifepo4 battery is a power lithium battery, and it is also composed of this structure without exception. Only when we clearly know the composition and structure of a modal product, will there be a solution when they are recycled.
lifepo4 has an olivine-type structure and is used as a cathode material in lithium batteries.
The theoretical capacity is 170mAh/g, and the actual capacity is 130-145mAh/g. It has the advantages of low price, good electrochemical performance, environmental friendliness and no pollution. Artificial graphite is a commonly used negative electrode material for lithium-ion batteries, and its crystals are stacked with hexagonal network plane specifications composed of carbon atoms, and have a layered structure. Graphite has good electrical conductivity and high crystallinity, and lithium ions are embedded in the graphite layer to form a thick lithium intercalation compound LixC6. During charging and discharging, the deintercalation reaction of lithium in graphite: C6 + xLi++xe-=LixC6
The electrolyte is an important part of the battery, which plays the role of conducting ions between the positive and negative electrodes of the battery, and is a bridge connecting the positive and negative materials. The diaphragm is one of the key inner layers of the battery cell. Its main functions are: to separate the positive and negative electrodes of the battery to prevent short-circuit between the two poles; it has the function of passing ions; the battery is overheated, and the current conduction in the battery is blocked by the closed-cell function.
The main production materials of the diaphragm are polyethylene PE and polypropylene PP. The conductive agent in the battery is to ensure that the electrode has good charge and discharge performance. A certain amount of conductive material is usually added during the production of the pole piece to improve the charge and discharge efficiency of the electrode.
The binder plays a role in bonding the active material and the foil, between the active material and the active material, and between the active material and the conductive agent. Although the amount is small, its role is irreplaceable.
Recycling of lifepo4 batteries
Now that the complete raw material composition of lifepo4 is clear, if you want to recover the useful metals and other materials in it, there will be corresponding technical methods to break through.
The cathode material of waste lifepo4 battery is rich in iron, lithium and other metals. Since the waste lifepo4 cathode material does not contain high-value metals such as cobalt and nickel, its recycling value is higher than that of other types of waste lithium-ion batteries such as NCM ternary materials. Low. Therefore, the waste lifepo4 batteries have higher requirements on the high efficiency and low cost of the recycling process.
The material obtained after the power battery is processed
1. Pre-treatment by physical method: dismantling the used lifepo4 battery (which can be directly charged and dismantled), heat and transport the electrolyte after crushing, volatilize the electrolyte below 140 degrees, and the volatilized materials are comprehensively sorted, Extract magnetic iron and nickel, plastic film, heavy metal pole plastic and positive and negative plates.
2. Cathode powder, aluminum pellets and plastic film are obtained by the process of crushing, silo, feeding, high-speed friction, aggregate dust collection, screening and other processes. The pole powder is cracked to obtain purer pole powder, which can be filtered and reused by gas.
3. Separate the metal particles and the polar powder, and separate the copper and aluminum by screening and specific gravity separation. The waste gas generated in each production area is transported to the waste gas treatment system through their respective pipelines for discharge up to the standard.
