電動車汰役鋰電池於循環經濟策略下的環境衝擊與抵換潛力

Abstract

隨著全球能源轉型與電動車市場的快速成長，鋰電池需求顯著增加。然而，台灣未來將逐漸面臨電動車鋰電池汰役潮，如何妥善管理這些廢棄電池，成為現今關鍵課題。此外，為配合我國政府計畫至2030年累計完成5,500 MW的儲能系統裝置容量，發展電動車汰役電池降階利用於儲能系統並搭配金屬冶煉回收貴金屬，對於降低環境衝擊與強化台灣關鍵原物料自主性具有重要意義。 本研究首先推估台灣在2025年至2050年間逐年汰役的電動車鋰電池數量，並建立金屬冶煉（Recycling）與降階利用（Repurposing）兩種循環經濟策略，透過生命週期評估方法，量化這兩種策略對台灣的環境衝擊差異。本研究設定兩個功能單位：一為處理2025至2050年間台灣所有電動車汰役鋰電池（個），另一為滿足此25年間每年新增儲能裝置容量的需求（MW/年）。 研究結果顯示，2025至2050年間，台灣累計將有約6.76百萬輛電動小客車投入市場，並產生1,058.4 kt與496.3 kt 的NMC與LFP汰役電芯。透過降階利用策略將汰役電池應用於儲能系統，可直接取代152.1 kt的新儲能電池生產，並在2039年後完全滿足台灣的儲能裝置需求，且2037年起，再生材料的產出可抵換原生材料的開採，顯示降階利用策略的資源抵換潛力。 根據生命週期評估結果，兩策略皆在淡水生態毒性、海洋生態毒性與人體致癌毒性具有顯著的環境衝擊。而降階利用策略對環境的影響均低於金屬冶煉策略，可有效減少約2.53百萬噸的CO2e排放、降低約52萬噸的化石燃料使用與節省3.63萬噸的水資源消耗。 整體而言，本研究驗證了電動車汰役電池降階利用於儲能系統的環境效益與資源抵換潛力。未來台灣政策應進一步完善電動車汰役電池降階利用的機制，以降低台灣對進口原物料的依賴，並促進電池產業鏈的永續發展。

With the global energy transition and the rapid growth of the electric vehicle (EV) market, the demand for lithium batteries has significantly increased. However, Taiwan will gradually face a wave of EV lithium battery retirements in the future, making the proper management of these retired batteries a critical issue today. Additionally, to align with the government's plan to achieve a cumulative installed capacity of 5,500 MW for energy storage systems by 2030, developing a strategy for repurposing retired EV batteries for energy storage systems, coupled with recycling for precious metal recovery, is crucial for reducing environmental impact and enhancing Taiwan's autonomy in key raw materials. This study first estimates the annual number of retired EV lithium batteries in Taiwan from 2025 to 2050 and establishes two Circular Economy strategies: Recycling and Repurposing. Using Life Cycle Assessment (LCA) methods, the study quantifies the environmental impact differences between these two strategies. Two functional units are defined: one for processing all retired EV lithium batteries in Taiwan from 2025 to 2050, and another for meeting the annual demand for new energy storage capacity over this 25-year period. The results indicate that approximately 6.76 million EV will be put on the market in Taiwan between 2025 and 2050, generating 1,058.4 kt and 496.3 kt of retired NMC and LFP battery cells, respectively. By applying the repurposing strategy for energy storage systems, it can directly replace the production of 152.1 kt of new energy storage batteries and completely meet Taiwan's energy storage capacity needs after 2039. Moreover, starting in 2037, the output of recycled materials can offset the extraction of virgin materials, highlighting the resource substitution potential of the repurposing strategy. According to the Life Cycle Assessment (LCA) results, both strategies exhibit significant environmental impacts in terms of freshwater ecotoxicity, marine ecotoxicity, and human carcinogenic toxicity. The repurposing strategy shows a lower environmental impact compared to the recycling strategy, effectively reducing CO2e emissions by approximately 2.53 million tons, decreasing fossil fuel usage by about 520,000 tons, and saving 36,300 tons of water resources. Overall, this study validates the environmental benefits and resource substitution potential of repurposing retired EV batteries for energy storage systems. Future policies in Taiwan should further improve the mechanisms for repurposing retired EV batteries to reduce reliance on imported raw materials and promote the sustainable development of the battery industry.