What issues should be noted when producing lithium iron phosphate batteries?

What issues should be noted when producing lithium iron phosphate batteries?

Lithium iron phosphate batteries have poor conductivity due to the low diffusion coefficient of lithium ions. Therefore, the current approach is to make their particles smaller, even at the nanoscale, in order to improve their charging and discharging speed by shortening the migration path of LI+and electrons (theoretically, the migration time is inversely proportional to the square of the migration path). But this brings a series of challenges to battery processing.

The first issue encountered is material dispersion: pulping is one of the most critical processes in battery production, and its core task is to evenly mix active substances, conductive agents, binders, and other materials to better utilize their properties. To mix well, you need to be able to disperse first. As the particle size decreases, the corresponding specific surface area increases, the surface energy increases, and the tendency for aggregation between particles strengthens.

The greater the energy required to overcome surface energy dispersion. Mechanical stirring is commonly used nowadays, and the energy distribution of mechanical stirring is uneven. Only within a certain area, with sufficient shear strength and high energy, can the aggregated particles be separated. To improve dispersion ability, one is to optimize the structure of the mixing equipment and increase the spatial proportion of the effective dispersion area without changing the maximum shear speed; One is to increase the stirring power (increase the stirring speed), increase the shear speed, and the corresponding effective dispersion space will also increase.

The former is a problem on the device, how much room for improvement is there, and there is no comment on coating online. The latter has limited space for improvement, as when the shear speed reaches a certain limit, it can cause damage to the material and result in particle breakage. A more effective method is to use ultrasonic dispersion technology. However, the price of ultrasonic equipment is relatively high. I recently contacted a company whose price is comparable to imported Japanese mechanical mixers. The ultrasonic dispersion process has a short time, reduced overall energy consumption, good dispersion effect of the slurry, effectively delays the polymerization of material particles, and greatly improves stability; Additionally, the dispersion effect can be improved by using dispersants.