Power lithium ion battery grouping method

Abstract

The invention discloses a power lithium ion battery grouping method. The method comprises 1, selecting cells belonging to the same batch, same type and same material system, carrying out a charging and discharging test on the cells and removing the cells unqualified in platform time and a charging constant current ratio, 2, selecting the cells with capacities greater than the lower limit capacity as qualified cells, dividing the cells into N grades according to a certain capacity range M and dividing the cells into P grades according to a certain charging constant current ratio, 3, standing the uncharged cells in a T DEG C environment for t1 days and standing the cells at the room temperature for t2 h, 4, testing voltage and internal resistance, removing the cells of which voltage and internal resistance exceed a certain range and dividing the cells with the same grade of capacities and the same grade of charging constant current ratios into Q grades according to a certain voltage scope, and 5, grouping the qualified cells with the same grade of capacities, the same grade of charging constant current ratios and the same grade of voltage. The method utilizes dynamic and static combination, takes into full consideration of single cell difference, improves grouping accuracy and greatly improves battery performances.

Description

【Technical field】 [0001] The invention relates to the battery field, in particular to a lithium iron phosphate power battery assembly method. 【Background technique】 [0002] In recent years, with the increasingly prominent environmental and energy issues, green and environmentally friendly electric vehicles have developed rapidly. As the power source of electric vehicles, the power battery pack directly determines the mileage and service life of the vehicle, and its importance is self-evident. [0003] The power battery pack is generally assembled and applied by hundreds, thousands, or even tens of thousands of single cells in a certain series-parallel manner. Due to differences in raw materials, manufacturing processes, production equipment, and environmental factors, there are certain differences in battery performance. The performance differences between individual batteries will lead to battery pack capacity reduction, shortened life, and even fire and explosion. and ot...

AI Technical Summary

Problems solved by technology

The above methods have their own advantages and disadvantages. The single-parameter matching method considers too few factors and has many defects in the actual application process, so it is not suitable for the matching of electric vehicle power batteries; the multi-parameter matching method selects more external eigenvalues , which can reflect the difference of the actual eigenvalues ​​inside the battery to a certain extent, and can sort out battery packs with better consistency, but this method has principle defects and cannot fully reflect the essential differences between power batteries; the dynamic characteristics ( Curve) grouping method can give full play to the performance of each single battery and improve its performance and life. However, this method has a large amount of data collection, complex processes, and strict requirements on various indicators. It is difficult to achieve manual grouping. Requires a computer program to be implemented

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