Matching method of power battery pack

Abstract

The invention discloses a matching method of a power battery pack. The power battery pack is obtained by sequentially connecting cells in parallel and in series. The matching method of the cells connected in parallel comprises: acquiring the capacity of each cell; performing cycle charge and discharge according to a charge-discharge rate required by the purpose, and recording charge and discharge curves; calculating a voltage-dependent electric quantity change rate dQ / dV curve of the discharge curve, wherein the dQ / dV curve has two peaks; searching for voltage values corresponding to the peaks according to the dQ / dV curve, finding electric quantity values of the corresponding cells in the discharge curve according to the voltage values, and calculating a difference Dn between the electric quantity values; acquiring the self-discharge rate of each cell; acquiring an internal resistance value of each cell; grading Dn according to the values into a plurality of large groups, and classifying the cells into the corresponding large groups according to the tested Dn values, wherein the cells in each large group are classified into a plurality of medium groups based on the value of the self-discharge rate, and the cells in each medium group are classified into a plurality of small groups according to the internal resistance values of the cells; selecting a plurality of cells in the same group for matching.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a battery assembly method. Background technique [0002] Since 2014, the state has provided financial subsidies for the promotion of new energy vehicles, which has greatly promoted the progress of key technologies, key materials and application products of lithium-ion power batteries. The development of new energy vehicles is inseparable from the progress of chemical energy storage devices, and lithium-ion batteries, as the mainstream chemical energy storage batteries, have received great investment in research and development and industry. For power batteries in electric vehicles, the focus is on safety, reliability and life. The research on the single power battery in the early stage has been relatively perfect, and the service life theoretically meets the requirements of electric vehicles. There is no serious problem in safety, and the operating economy is gradually approaching the l...

AI Technical Summary

Problems solved by technology

The simplest matching group is single-parameter matching group, which only considers the rated capacity, which is the case for the early matching group, but single-parameter matching group, the battery pack made of single power battery with 1500 cycle life, the cycle life is less than 1 / 10 of the monomer

Dynamic matching, considering the degree of overlap of standard discharge curves, this method either has a very low matching rate, or fails to grasp the key essence, and it is difficult to exceed 1 / 3 of the life of the monomer after matching

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