鉛酸蓄電池破損分析

Failure Analysis of Lead Acid Battery

台灣某火力電廠儲煤場蓄電池室發生使用中蓄電池著火事故，經現場及初步觀察得知，破損的主要位置為蓄電池的正極端，且有嚴重燒毀情形；由於電池在使用中發生著火燒毀是未曾遭遇過的事件，值得進一歩釐清肇因。本文從背景說明、外部巨觀檢視、破斷面觀察、破損材料金相分析、腐蝕產物分析等多方面探討鉛酸蓄電池破損原因；根據研究結果顯示破損主因為腐蝕，影響因素包括材料本身瑕疵、電極氧化之自然反應、蓄電池本體極板設計及環境溫度效應等；推論破損起源為電池導線接頭位置由於腐蝕行為造成導電路徑縮小，在循環充放電時因電流密度過大，發生局部過熱而燒毀。

In Taiwan, there is a fire accident occurred in the battery storage room of a thermal power plant. After field observation and preliminary investigation, the main failure was happened in a lead acid battery’s positive terminal, which was seriously burned. Due to the use of the battery in the fire burned never encountered before, it is worth to further clarify the failure cause. In this study, background information, macro observation, failure cross section investigation, metallographic observation of failure material, corrosion products analysis were used to investigate the failure cause of the lead acid battery. According to the results of this study, corrosion is the main failure cause, where the other influencing factors including material’s defects, electrode oxidation reaction, design of battery’s electrode plates and environment temperature. The estimated failure mechanism is proposed, the electrical conducting area of battery’s positive terminal was reduced due to corrosion, which caused electrical resistance increased. After cyclic charge and discharge, the current became too high for the battery, which leaded to a high temperature and caused the battery being burn out.