A life-accelerated prediction method for lithium-ion batteries based on low-temperature cycling

Abstract

The invention relates to a life-accelerated prediction method of lithium-ion batteries based on low-temperature cycles. The method makes full use of the characteristics of severe attenuation of lithium-ion batteries at low temperatures, and attenuates the lithium-ion batteries to a specified SOC at low temperatures, and then returns to normal temperature. Cycle, and after three cycles, the discharge capacity is still higher than 80% SOC. The numerical relationship between the number of cycles at low temperature and the number of cycles attenuated to 80% SOC at room temperature can be determined to determine the performance of lithium-ion batteries at different temperatures and at different rates. Methods of life assessment. Compared with the prior art, the present invention has the advantages of universality, simplicity and safety, convenient operation, rich application scenarios and the like.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a method for accelerating the life prediction of lithium-ion batteries based on low-temperature cycles. Background technique [0002] In recent years, lithium-ion batteries, as the main power system of electric vehicles, have been rapidly popularized due to their unique advantages such as long service life, low self-discharge rate, high power density, high energy density, and no pollution. Although lithium-ion batteries have obvious advantages, they have gradually replaced traditional power batteries such as lead-acid batteries and are used in power batteries for electric vehicles. However, for the evaluation of the long life of lithium-ion batteries, it is impossible to rely on conventional testing methods to reduce them to SOC (State of charge, that is, state of charge) is less than 80% of the number of cycles to evaluate life. [0003] Experimental studies have shown that t...

AI Technical Summary

Problems solved by technology

Especially when the battery works at a temperature lower than 10°C or higher than 60°C, the cycle life begins to decline gradually

Most of the existing technologies use high-temperature cycles for detection. However, due to the increase in the viscosity of the electrolyte at low temperatures, the diffusion coefficient and electrochemical reactivity of lithium ions and electrons are reduced, resulting in significant attenuation of electrical properties; while at high temperatures, the coefficient increases. The attenuation is mainly due to the obvious high-temperature side reactions, and the high-temperature cycle is likely to cause flatulence and cause safety problems, which cannot accelerate the prediction of battery life; in addition, due to the inconsistency of each battery, the high-temperature cycle method cannot be applied to all lithium-ion batteries and lithium ion capacitor

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