比較不同型態電解質之鋰離子電池碳足跡

Abstract

隨著電氣化趨勢的來臨，以及鋰離子電池技術的不斷進步，其作為儲能裝置的需求也持續上升。先進國家中，歐盟已入法關於電池的法規 (EU Batteries Regulation) ，2023年8月新法施行。新的歐盟電池法規將確保未來電池具有低碳足跡，使用最少的有害物質、更少的來自非歐盟國家的原材料，而根據「歐洲綠色政綱」(European Green Deal)的循環目標，「電池法規」是歐洲第一部採用全生命週期方法的立法。 本研究主要探討，傳統液態鋰離子電池與硫化物固態鋰離子電池之電解質碳足跡。研究透過篩選出最有前景發展價值之硫化物固態電解質，令其與傳統液態電解質進行生命週期評估（Life-cycle assessment, LCA），以量化分析，解構兩種不同型態之電解質，所可能產生之碳排，並將傳統液態鋰離子電池之液態電解質，與固態鋰離子電池之固態硫化物電解質，之各項目碳排進行交叉比較。 根據研究模擬結果顯示，製造1 kWh固態鋰電池之總碳足跡為 47.95 kg CO₂-eq，其中來自化石能源之排放為 47.72 kg CO₂-eq，佔比達 99.5%；生物來源貢獻為 0.074 kg CO₂-eq，土地使用變化則為 0.15 kg CO₂-eq。而生產1 kWh液態鋰電池之總碳足跡為 17.95 kg CO₂-eq，其中化石來源碳排佔 17.89 kg CO₂-eq（99.7%），生物來源為 0.029 kg CO₂-eq，土地使用變化造成之碳排為 0.033 kg CO₂-eq。整體結果顯示，兩種電解質之碳排熱點皆為化石燃料燃燒。 硫化物固態電解質，有望成為次世代鋰離子電池儲用能解方，單論原料與製程階段，需注意原料選用及製程電力來源。相較於技術穩定、成本低的液態鋰離子電池，欲成為有競爭力的新一代產品，還需克服以上問題，才能打開量產市場進行商業化佈局。

With the global trend toward electrification and ongoing advancements in lithium-ion battery (LIB) technologies, the demand for efficient energy storage continues to grow. In response, the European Union enacted the 2023 EU Batteries Regulation to ensure future batteries maintain low carbon footprints, minimize hazardous substances, and reduce reliance on non-EU raw materials. As the first EU law to adopt a full life cycle approach, it aligns with the circular goals of the European Green Deal. This study compares the carbon footprints of conventional liquid LIBs and sulfide-based solid-state LIBs through life cycle assessment (LCA). The most promising sulfide solid electrolytes were selected and benchmarked against traditional liquid electrolytes. The analysis focuses on emissions during the Cradle-to-Gate phase, quantifying and comparing environmental impacts. Results show that producing 1 kWh of a solid-state LIB emits 47.95 kg CO₂-eq, with fossil sources accounting for 99.5%. In contrast, the liquid LIB emits 17.95 kg CO₂-eq per kWh, with 99.7% from fossil sources. Both systems reveal fossil fuel use as the major emission hotspot. While sulfide solid electrolytes offer strong potential for next-generation LIBs, their raw material choices and electricity sources during production significantly impact emissions. Compared to the cost-effective and mature liquid LIBs, solid-state alternatives require further technical improvements to achieve commercial viability.