Lithium metal battery module and charging and discharging control method

Abstract

The invention belongs to the technical field of battery manufacturing, and discloses a lithium metal battery module and a charge and discharge control method. The battery module comprises a plurality of lithium metal battery single cells and a battery management system, the battery management system comprises a transformation system with adjustable conversion efficiency, all the single lithium metal battery cells are separately connected with the battery management system, and during charging, the battery management system controls all the single lithium metal battery cells or all the first battery cell combinations to be connected in parallel; during discharging, the battery management system controls the lithium metal battery monomer cells or the second cell combination to discharge one by one; and the battery management system detects the terminal voltage of the lithium metal battery connection group in real time, and adjusts the terminal voltage of the lithium metal battery connection group to the rated voltage through the voltage transformation system, so that the cycle performance of the lithium metal battery module can be effectively improved, and the service life of the lithium metal battery module is prolonged.

Description

Technical field [0001] The present invention relates to the field of battery charge and discharge technologies, and more particularly to a lithium metal battery module and a charge and discharge control method. Background technique [0002] The lithium metal battery module consists of a plurality of lithium metal battery cells. Conventional lithium metal battery modules The charge and discharge mode employed is: skewer in a fixed manner according to the rated voltage required by the electric device, and then charge and discharge. [0003] If the lithium metal battery module obtained by the conventional module assembly method has the following issues: [0004] 1, according to the existing charging method, the charging current of the lithium metal battery module is large, resulting in a lithium metal battery cell negative electrode surface to deposit in a faster rate, and it is easy to uniformly deposit to produce a lithium branch. The crystal greatly reduces the cycle performance ...

AI Technical Summary

Problems solved by technology

[0004] 1. According to the existing charging method, the charging current of the lithium metal battery module is relatively large, resulting in the deposition of lithium on the surface of the negative electrode of the single cell of the lithium metal battery at a relatively fast rate, which is prone to uneven deposition and lithium branches. Crystal, greatly reducing the cycle performance of lithium metal battery modules;

[0005] 2. According to the existing discharge method, it can only be discharged according to the same discharge circuit as the charging process, and it is impossible to accurately control the discharge voltage and current of each single lithium metal battery cell. However, the researchers of this application have conducted long-term research Accidentally found that the same charge-discharge current ratio is very unfavorable to the cycle performance of lithium metal single cells;

[0006] 3. Due to the long-term use of lithium battery cells after leaving the factory, certain performance differences will gradually occur between each lithium battery cell, so there are inconsistencies between multiple lithium battery cells in the same lithium metal battery module , Lithium metal battery modules will cause greater differences in the state of lithium battery cells (such as SOC, voltage, etc.) after continuous charge and discharge cycles, that is, the difference between multiple lithium battery cells in the same lithium metal battery module The inconsistency between them becomes larger after continuous charge and discharge cycles, resulting in overcharge or overdischarge of some lithium metal single cells during charging, which will accelerate the performance degradation of lithium metal battery modules and eventually lead to premature failure of lithium battery modules