LiFePO4 battery production process
1. Iron phosphate drying to remove water
(1) Drying process in the drying room: The stainless steel sagger is filled with raw material iron phosphate and placed in the drying room. The temperature of the drying room is adjusted to 220±20℃, and it is dried for 6-10 hours. The discharge is transferred to the next process to the rotary furnace for sintering.
(2) Rotary kiln sintering process: After the rotary kiln is heated up and the nitrogen flow reaches the requirements, feed (materials from the drying room of the previous process), adjust the temperature to 540±20℃, and sinter for 8-12 hours.
2. Grinding machine mixing process
During normal production, the two grinders are put into operation at the same time, and the specific feeding and operation of the two equipment are the same (one can be operated separately during commissioning), and the procedure is as follows:
(1) Lithium carbonate grinding: weigh 13Kg of lithium carbonate, 12Kg of sucrose, and 50Kg of pure water, mix and grind for 1-2 hours. pause.
(2) Mixing and grinding: Add 50Kg of iron phosphate and 25Kg of pure water to the above mixed solution, and mix and grind for 1-3 hours. Shut down, the output is transferred to the dispersing machine. Sampling to measure particle size.
(3) Cleaning: Weigh 100Kg of pure water, clean the grinder 3-5 times, and transfer all the lotion to the dispersion machine.
3. Dispersing process of dispersing machine materials
(1) Transfer the material about 500Kg (including the material for cleaning the grinder) to the dispersing machine together with the materials that have been mixed by the two grinders (or 1 grinder twice), and then add 100Kg of pure water, adjust the mixing speed, and fully Stir and disperse for 1-2 hours, waiting to be pumped into the spray drying equipment.
4. Spray drying process
(1) Adjust the inlet temperature of the spray drying equipment to 220±20°C, the outlet temperature to 110±10°C, and the feed rate of 80Kg/hr. Then, start spray drying to obtain dry materials.
(2) The solid content can be adjusted to 15%~30% according to the spray particle size.
5. Hydraulic press material briquetting and charging adjust the pressure of the hydraulic press to 150 tons and 175 tons respectively, and load the spray-dried material into the mold, hold the pressure for a certain period of time, and compact it into a block. Load the sagger into the push plate furnace. At the same time, several sets of bulk samples were put in to compare with the compressed materials.
6. The pusher furnace is sintered and the temperature is increased first, and nitrogen is passed through to reach the atmosphere requirement of 100ppm or less. Push the sagger into the pusher furnace, press the heating section 300-550℃ for 4-6 hours; the constant temperature section 750℃ for 8-10 hours; cooling down The section is carried out for 6-8 hours, and the material is discharged.
7. Rolling ultra-fine grinding
The material burned in the pusher furnace is input into the ultra-fine grinding, the speed is adjusted, and the roller grinding is carried out and then sent to the ultra-fine grinding for grinding. Each batch is sampled to test the particle size.
8. Screening and packaging
The grinding materials are screened and packaged. Two specifications: 5Kg and 25Kg.
9. Inspection and storage
