A method for cyclic formation of low current disturbance in the vicinity of high SOC of lithium battery

Abstract

The invention relates to the technical field of lithium battery formation, in particular to a method for cyclic formation of low current disturbance in the vicinity of a high SOC of a lithium battery.The method for cyclic formation of low current disturbance in the vicinity of high SOC of the lithium battery comprises the following step: (1) according to the SOC curve of the lithium battery, determining the SOC of the lithium battery; (2) charging the lithium battery to 50% SOC to 80% SOC at a first charge rate, standing for 0.5-2h; (3) performing cyclic charging and discharging on the lithium battery at charge-discharge rate of 0.05 to 0.2 C in the range of + / -3% to + / -9% SOC based on the current SOC, performing vacuum treatment on the battery at the same time, and after the cycle is finished, standing for 0.5-2h; and (4) discharging the lithium battery to a lower limit voltage at a first discharge rate. The lithium battery is subjected to low current cyclic formation in the vicinityof a relatively high SOC, which is in favor of full occurrence of a side reaction inside the battery, thereby forming a stable and compact SEI film, and generated gas is effectively discharged through vacuum treatment, the smoothness and uniformity of the interface of a pole piece are improved, and the long cycle life of the lithium battery is prolonged.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a small current disturbance cycle formation method near high SOC of lithium batteries. Background technique [0002] As a new type of high-energy green battery, lithium-ion batteries are widely used in portable electronic products such as notebook computers and mobile phones, and are expanding to large and medium-sized energy storage equipment and new energy electric vehicles. The cycle life of lithium batteries has always been the focus of attention in the industry. In the process of lithium battery preparation, a crucial link that affects its life is the formation process of single batteries. During the first charge and discharge process, the lithium battery active material surface A layer of solid electrolyte interface film (SEI film) will be formed and a large amount of gas will be generated. The SEI film will prevent further reduction and decomposition of the elect...

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Problems solved by technology

[0003] The Chinese invention patent with the application number CN201711128167 adopts the formation method of step voltage charging and discharging, which is only suitable for lithium batteries whose positive electrode material is lithium-rich manganese-based materials; the Chinese invention patent with the application number CN201710765868 adopts negative pressure vacuuming in stages The formation method can effectively discharge the gas in the lithium battery and form a uniform and smooth formation interface, but the operation process is relatively cumbersome; the Chinese invention patent with the application number CN201711338702 adopts gradient current segmental formation, although it can form dense and stable SEI film, but the cycle performance of the battery still needs to be improved

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