Recently, especially from 2015 to 2017, Thailand produced waste of lead-acid batteries (LABs) around 11,000 tons/year on an average which traction battery accounted for around 44% or 4,800 tons/year. It was estimated that 16% of spent LABs was considered as improper management. According to literature reviews, 22% by weight of LABs is an electrolyte which is sulfuric acid. Sulfuric acid used in the battery is a strong acid with pH lower than 2. A leakage of sulfuric acid during disassembling or battery cell transportation can lead to environmental impact and ecotoxicity. A primary goal of this study is to assess the environmental impact of spent sulfuric acid from expired traction battery with and without treatment before discharge. A material flow analysis illustrated a quantity of traction battery used to calculate the amount of spent sulfuric acid. The highest total amount of spent sulfuric acid (which was 1,808 tons/year from 1,299 tons/year of traction batteries and 509 tons/year of improper management) was found in 2016. These most massive quantities were used to evaluate the impact on each scenario. The result showed that directly discharged spent sulfuric acid caused higher environmental impact load than treated one. Spent sulfuric acid played a significant role in the impact potentials. Marine aquatic ecotoxicity had the greatest impact compared to the other categories. The assessment of scenario comparison assured that pH adjustment of spent sulfuric acid was able to alleviate environmental impacts for expired battery management.