With the development of lithium iron phosphate batteries and actual market demand, the requirements for high-rate discharge performance of lithium iron phosphate batteries will continue to increase. Especially in electric vehicles and power tools, power lithium iron phosphate batteries have become more popular. Welcome type. So how to increase the discharge rate of lithium iron phosphate battery?
Mind map of increasing the discharge rate of lithium iron phosphate battery:
1. Improve the quality of carbon coating. Large-rate discharge makes the LFP core body temperature rise sharply, and the temperature rise of the coating cannot keep up, resulting in weak carbon coating and increased resistance, which affects battery rate discharge.
2. R&D and use of dedicated cathode materials and electrolytes.
The materials of the positive electrode and the electrolyte are very important, and the performance of different manufacturers is very different.
3. Improve the quality of the coating process
Speaking of the production process, the coating is still a bit technical. It is impossible to achieve the technology of secondary coating and new additives in foreign countries in China.
4. Control the compaction density, improve the compaction density quality of the pole piece, and add AC, which has a great influence on improving the battery discharge rate.
5. Decreasing the particle size is not a method, because 1um particles and 10um frequency particles are actually the same in magnification performance. Of course, there may be a difference between 10um and 20um. If the calibration is smaller, the specific surface area may be lower. If it increases, the homogenization will have problems, and it is likely that agglomeration will not break up, and the slurry will pilling and trouble particles. The most effective way is to reduce the thickness of the electrode.
At the same time, optimize the formula in the ratio, control the conductive agent, and then choose a diaphragm with a larger gap and an electrolyte with a higher conductivity.
6. The pole piece should be thinner, the diaphragm gap should be larger, the electrolyte viscosity should be lower, and the pole ear should be larger.
7. Develop a new homogenate formula, using a small particle size cathode material.
8. Regardless of the positive or negative active material, there will be problems of expansion and contraction. Generally, the negative electrode material has a 20% expansion and contraction rate, while the positive electrode material like LFP has a 6% yield. The positive and negative active material particles have little contact with the particles, the gap is enlarged, and the base is somewhat separated from the collector, resulting in the intermittent phase of the electron and ion transmission path, which becomes a dead active material and no longer participates in the electrode reaction. Therefore, the cycle life is reduced. The VGCF carbon tube has a large aspect ratio. Even after the positive and negative active materials expand and contract, the gap between the active material particles can be bridged by the VGCF carbon tube, and the transmission of electrons and ions will not be interrupted.
9. The microstructure of the VGCF carbon tube is a hollow multi-tube wall, which allows the positive and negative electrodes to absorb a large amount of electrolyte, so that lithium ions can be inserted or deintercalated smoothly and quickly. Therefore, it is conducive to high-rate charge and discharge.
10. It is a high-strength fibrous material with a large aspect ratio, which can increase the flexibility of the electrode plate, and the adhesion between the positive or negative active material particles or the adhesion between the electrode plates is strong, and it will not be deflected And cracking off the powder.
11. VGCF is essentially of high electrical conductivity and thermal conductivity. The positive electrode active material has poor electrical conductivity. Adding VGCF can improve the electrical conductivity of the positive electrode active material, and also increase the thermal conductivity of the positive electrode or the negative electrode, which is good for heat dissipation.
12. The structural design of the battery also has a great influence. When conditions permit, the pole pieces should be made as thin as possible, and the area of the positive and negative electrodes should be enlarged to reduce the true tangential discharge current density under high magnification. In addition, the design of the current collector is also very good. Importantly, reduce the polarization as much as possible, and the corresponding battery heating will be reduced, the temperature rise will be small, and the life of the electric bulb under high magnification will be correspondingly improved.
13. Choosing MCMb as anode material is beneficial to rate discharge. The positive electrode should control the particle size and specific surface area.
The electrolyte can be considered to have low viscosity and high conductivity. The diaphragm can be considered to have a larger porosity and thicker, which is safer. In terms of conductive agent, you can consider using mixed conductive agent to control the content and disperse evenly! As for the adhesive, water-based glue can also be considered. Relatively speaking, water-based glue has advantages over oil-based glue in terms of rate discharge. When designing the battery, you can consider thin pole pieces, multiple tabs, or change the width and position of the tabs.
14. Improve the dispersion ability, adjust the compaction solubility, select the appropriate LFP, and add an appropriate amount of PVdF.
In the future, JUNLEE Energy, which has been committed to battery research and development, is a challenge and an opportunity. The R&D team of engineers will provide the world with more economical new energy batteries, and will improve lithium-ion battery technology to reduce the total cost.
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