Lithium battery assembly method and device

Abstract

The invention provides a lithium battery grouping method and device. The method comprises the steps: screening a plurality of lithium batteries according to capacity, open-circuit voltage, self-discharge rate and AC internal resistance to obtain a first lithium battery pack; charging and discharging the first lithium battery pack to obtain first direct-current internal resistance corresponding toa second lithium battery pack and second direct-current internal resistance corresponding to a third lithium battery pack respectively; obtaining direct-current internal resistance difference according to the first direct-current internal resistance and the second direct-current internal resistance; obtaining relaxation voltage of each lithium battery in the third lithium battery pack; screening the lithium batteries in the third lithium battery pack according to the direct-current internal resistance difference to obtain a fourth lithium battery pack; screening lithium batteries in the fourthlithium battery pack according to the relaxation voltage to obtain a fifth lithium battery pack; and grouping the lithium batteries in the fifth lithium battery pack to obtain the lithium battery pack, so that the lithium batteries can be effectively grouped, the consistency of the single lithium batteries in the grouped lithium battery pack is improved, and the service life of a battery system is prolonged.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a method and a device for grouping lithium batteries. Background technique [0002] Due to its high energy density, long cycle life, safety and environmental protection, lithium batteries have been widely used in consumer electronics, new energy vehicles and energy storage fields. Since the rated voltage of a single lithium battery is generally around 3.70V, and the rated capacity of a lithium battery is relatively small, a single lithium battery alone cannot meet the applications in fields such as energy storage and new energy vehicles, so it is necessary to use a single lithium battery The batteries are connected in series and parallel to meet the voltage and capacity requirements required by the application terminal. Therefore, when the single lithium batteries are connected in series and parallel, the consistency of the single lithium batteries is particularly impo...

AI Technical Summary

Problems solved by technology

[0003] In the existing battery matching methods, static matching is the main method, that is, the open circuit voltage, discharge capacity, AC internal resistance and self-discharge rate (K value) of the lithium battery are screened. This method mainly focuses on the static consistency of the battery Although the operation is simple and the cost is low, it is impossible to screen out the differences of lithium batteries under complex working conditions. As the use time and frequency of lithium batteries increase, the differences between individual lithium batteries will become more and more Therefore, the static screening is limited to the series-parallel application of a small number of single batteries and the application environment that does not require high consistency of lithium batteries. For the series-parallel application under complex working conditions, the Gauge IC is used. Simulation, using computer software to characterize the changes of various index parameters (capacity, voltage, current and temperature) of lithium batteries in the process of charging and discharging in real time, but this method is costly

Images