Ultralow temperature lithium iron phosphate power battery and preparation method thereof

Abstract

The invention provides an ultralow temperature lithium iron phosphate power battery. The ultralow temperature lithium iron phosphate power battery comprises a cathode plate, an anode plate, a diaphragm and a low-temperature electrolyte. The cathode plate comprises a cathode collector piece and nano lithium iron phosphate cathode slurry with which the cathode collector piece is coated. The nano lithium iron phosphate cathode slurry is prepared through the high-speed dispersion process that a glue solution and an active-matter-containing component are beaten separately, in other words, the glue solution and the active-matter-containing component are separately prepared. The glue solution is prepared according to a certain proportion; the active-matter-containing cathode powder raw material and a solvent are mixed according to a certain proportion and dispersed uniformly at high speed to form cathode premixed slurry; the prepared glue solution is added into the cathode premixed slurry step by step, by means of the stirring mode in which revolution and high-speed autorotation are combined, the glue solution and the cathode premixed slurry are fully mixed, stirred and dispersed uniformly, and then the cathode slurry is obtained. The anode plate comprises an anode collector piece and modified graphite anode slurry with which the anode collector piece is coated. The electrolyte is prepared from lithium salt, a solvent and an additive.

Description

[0001] 【Technical field】 [0002] The invention relates to the field of power batteries, in particular to an ultra-low temperature lithium iron phosphate power battery and a preparation method thereof. [0003] 【Background technique】 [0004] The conductivity of lithium iron phosphate is poor, and the diffusion rate of lithium ions is slow, resulting in poor low-temperature performance. The discharge capacity of conventional lithium iron phosphate batteries at -35°C is only 20%-40% of the discharge capacity at room temperature, which seriously affects the performance of electric vehicles at low temperatures. operation and use. At present, nano-scale lithium iron phosphate is generally used to increase its electronic and ionic conductivity by encapsulating carbon or doping with other elements, thereby improving the rapid charging capacity of the battery. However, after the particle size is nano-sized, the agglomeration among the particles becomes more serious, resulting in diff...

AI Technical Summary

Problems solved by technology

The use of dry mixing and beating technology can achieve good dispersion of nano-lithium iron phosphate, but it requires high equipment and is relatively expensive, which greatly affects the use of nano-scale lithium iron phosphate to improve low-temperature charge and discharge performance.

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