當18650鋰離子電池發生熱失控時，鋰離子電池蓋中的電流中斷裝置（CID）和排氣機構通過在內部壓力增加時對電池進行電氣隔離，以及在外殼破裂之前釋放內部壓力，從而降低了熱失控風險。在文獻[1]兩次實驗中觀察發現，部分18650鋰離子電池之結構有配置電流中斷裝置 （Current Interrupt Device, CID），其於過充狀態下未能有效啟動其保護機制，導致仍有可能進一步發生熱失控（Thermal Runaway）現象。此一觀察結果顯示，當第一道安全保護機制失效時，電池第二道安全保護機制為設置於電池端蓋內之排氣結構，其功能與效能將顯得尤為關鍵。因此，本文旨在探討不同幾何設計之排氣結構在鋰離子電池發生熱失控時，對其內部壓力變化、洩壓至一大氣壓力時間與排氣流速之比較。本文研究採用商用三維電腦輔助設計軟SOLIDWORKS 建立電池端蓋排氣結構模型，並使用商業軟體Fluent® version 2024 R2 ( ANSYS Inc., 2024a ) 進行（Computational Fluid Dynamics, CFD）模擬，以評估各幾何結構於熱失控過程中之流場行為與壓力釋放特性。最終根據模擬所得數據，進行定量比較與分析，以提供未來鋰離子電池安全結構設計之參考依據。

This study investigates the effects of different venting structure geometries on the pressure relief performance of 18650 lithium-ion batteries during thermal runaway. Previous studies have shown that the Current Interrupt Device (CID) may fail to activate under overcharge conditions. Therefore, the venting structure integrated into the battery cap serves as a critical secondary safety mechanism to release internal pressure and prevent casing rupture. Three-dimensional models of different venting structures were developed using SOLIDWORKS, and computational fluid dynamics simulations were conducted using ANSYS Fluent. The designs were compared based on internal pressure evolution, pressure relief time to atmospheric pressure, and venting flow velocity. The simulation results clarify the relationship between venting geometry and pressure relief performance and provide useful guidelines for optimizing the safety design of lithium-ion batteries.

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