The Study on Reliability Tests and Life Estimation for Single Secondary Lithium Cells

• Main Authors: shao-wen zhou, 周紹文
• Other Authors: Sheng-Chai chi
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/43070888042317302199

碩士 === 華梵大學 === 工業工程與經營資訊學系碩士班 === 96 === With the dramatic progress on new technology development, recently, portable electronic products for personal utilization become popular in the current market. As a key component, the lithium-ion secondary battery performs very well for providing the required power to drive these products. Nevertheless, life-span and safety of a battery are always two essential problems for battery manufacturers. Traditionally, some reliability tests implemented by lithium-ion cell producers or up-stream packaging firms mostly focus on the environmental tests defined in the specifications of a national standard. Usually, these tests can only response the product capability of passing the required specification under certain environmental situation without reaching the most important purpose of reliability tests for evaluating the information about time and further improving it. This research takes lithium-ion secondary cells as the experimental subjects. The accelerated life test with some strict environmental conditions in the reliability tests is employed to cause for product failure within a short period of time and further to evaluate their performance on life-span. In the data analysis, a modified Conffin-Manson formula is utilized to compute the accelerated factor; the K-S hypothesis test is used for fitting an appropriate probability distribution of product life; and the Arrhenium model is applied for estimating the life-span of a lithium-ion cell under the normal condition of applications. In the experiments, this research carries out some accelerated life tests of stress cycling between cold and hot and judges if the failure rate curves for three different types of temperature stress cycling were parallel in order to inspect the correctness of the tests. From the results obtained, this research proves the proposed methodology is very useful for evaluating the quality performance and reliability of a lithium-ion cell.