Measurement of Battery Residual Capacity

• Main Authors: Wei-Tso Lin, 林威佐
• Other Authors: Yung-Yaw Chen
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/23908015529804173476

碩士 === 國立臺灣大學 === 電機工程學研究所 === 89 === The goal of research for this thesis is to develop measurement methodologies for battery residual capacity. The focus of our method is on the practical side and we emphasize accuracy as well as cost as the major factors of design. The proposed measuring method is based on the law of energy conservation, which is rooted on fundamental physical theories rather than particular electrochemical characteristics of the batteries. The method is intended to be valid for all kinds of batteries. Our fundamental assumption is that (Battery residual capacity) = (Battery initial capacity) — (Battery used capacity). In order to accurately estimate the battery residual capacity at any time, accurate measuring of the battery initial capacity and the battery used capacity are required. The measurement of the initial capacity is based on the improved open-circuit voltage measurement, which compensates the effect of battery aging, environmental temperature and self-discharging. The measurement of the used capacity is based on the improved coulometer measurement, which compensates the effects of output current and environmental temperature. The relationship between the voltage slope and the battery initial capacity is also studied, which helps to obtain the accurate value of initial battery capacity by measuring the slope of the battery voltage. Relevant experiment results show that the proposed method is feasible and is able to come up with accurate estimate of the residual capacity of a battery.