Lithium ion secondary battery and electronic product comprising same, electric vehicle and mechanical equipment

Abstract

The invention discloses a lithium ion secondary battery and an electronic product comprising same, an electric vehicle and mechanical equipment. The lithium ion secondary battery comprises a battery cell and an electrolyte, wherein a positive electrode active material of the battery cell comprises a lithium-manganese-based positive active material; the electrolyte comprises a solvent, a lithium salt and an additive, wherein the additive comprises vinylene carbonate; the percentage q of the weight of the electrolyte to the total weight of a positive electrode active material layer in the battery cell, the weight percentage r of vinylene carbonate in the electrolyte, the compaction density s of a negative electrode active material layer in the battery cell and the weight percentage p of a manganese element in the positive electrode active material meet the condition that q.r.s / p is larger than or equal to 0.05 and smaller than or equal to 6, the units of q, r and p are all wt%, and the unit of s is g / cm < 3 >. The lithium ion secondary battery provided by the invention can simultaneously consider relatively high safety performance, cycle performance and storage performance.

Description

[0001] This invention is a divisional application based on the invention with the application number 201811094862.X, the application date is September 19, 2018, the applicant is Ningde Times New Energy Technology Co., Ltd., and the invention name is "lithium-ion secondary battery". technical field [0002] The invention belongs to the technical field of batteries, and in particular relates to a lithium ion secondary battery. Background technique [0003] Lithium-ion secondary batteries can provide stable voltage and current, have a high voltage platform, high energy density and wide temperature range, no memory effect, and are environmentally friendly and easy to carry. Mainstream power source for tools and mechanical equipment. [0004] With the application of lithium-ion secondary batteries more and more widely, people put forward higher requirements on the safety performance of lithium-ion secondary batteries. The positive electrode active material has an important influ...

AI Technical Summary

Problems solved by technology

However, due to the disproportionation reaction of manganese in the positive electrode, the generated Mn 2+ Soluble in the electrolyte and migrate to the interface of the negative electrode, ion exchange with the lithium in the negative electrode, occupy the lithium intercalation position of the negative electrode, and is not easy to come out, resulting in a decrease in the lithium storage capacity of the negative electrode

Moreover, the lithium ions released by ion exchange will no longer be able to participate in the deintercalation between the positive and negative electrodes, resulting in capacity loss.

This leads to the deterioration of the cycle performance and storage performance of lithium-ion secondary batteries, and the impact is more serious at high temperatures (above 40°C)

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