Secondary battery and application thereof

Abstract

The invention provides a secondary battery and application thereof. By regulating and controlling the residual lithium quantity WR of a negative pole piece in a lithium-supplemented secondary battery, the WR is designed within the limited range of the secondary battery, so that the influence on the comprehensive performance of the battery due to excessive or insufficient lithium supplement is avoided, added lithium can directly supplement active lithium consumed by a negative electrode SEI film and an irreversible compound formed in the first charging and discharging process of the battery, and in addition, a part of lithium is reserved to supplement lithium continuously consumed in the circulation and storage process of the battery, so that the lithium-supplemented secondary battery with relatively excellent comprehensive performance is obtained, the first coulombic efficiency, the cycle performance and the storage performance of the battery are improved, and the DC internal resistance DCR of the battery is reduced.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to a secondary battery and its application. Background technique [0002] In response to the requirements of national policies, the energy density requirements of lithium-ion batteries are getting higher and higher. However, the theoretical energy density of the traditional graphite system is low, and the actual energy density has basically reached the limit. The new high-capacity alloy composite materials currently developed are more and more widely used because of their high theoretical energy density, such as silicon-based, tin-based and metal oxides. However, whether it is a traditional graphite material or a new high-capacity alloy composite material, the SEI film will be continuously damaged and repaired during the battery cycle and storage process, resulting in the continuous consumption of active lithium. In addition, for the new type of high-capacity alloy composite mater...

AI Technical Summary

Problems solved by technology

[0004] One of the purposes of the present invention is to provide a secondary battery that solves the problem that the secondary battery still has poor comprehensive performance even if the amount of lithium replenishment is difficult to determine at present; the secondary battery regulated by the present invention can reasonably supplement The active lithium consumed by the formation of the negative electrode SEI film and irreversible compounds during the first charge and discharge process is eliminated, thereby comprehensively improving the performance of the battery

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