透過全電池資訊得到鋰鍍層過電位並應用到充電策略

Abstract

鋰離子電池 ( Lithium-ion Batteries, LIBs ) 快充最主要的問題是產生副反應在負極上形成鋰金屬沉積的鋰鍍層 ( Lithium Plating ) ，該副反應會造成電池容量下降的情況，嚴重者會造成內部短路產生危險。因此，能預防plating發生成為快充的主要議題。在本論文中，利用量測的實驗數據進行plating current的取值，並擬合出plating current與定電流 ( Constant current, CC ) 充電時間關係，以計算platnig current為0的時刻點以達到預防plating的效果，並透過Bulter-Volmer ( B-V ) 方程式利用所得plating current進行plating overpotential的計算，利用全電池數據得到半電池的資訊。在充電策略應用上，透過實驗及plating current的擬合結果進行快充，以達到CC充電時間的減少，並且不造成鋰鍍層生成。此外，討論鋰離子電池在不同工作環境下，包含充電速度 ( Crate )、健康度 ( State of Health , SOH ) 之鍍鋰層的趨勢及生成量的原因。

The primary issue with fast charging lithium-ion batteries ( LIBs ) is the occurrence of side reactions that lead to the formation of lithium metal deposits ( Lithium Plating ) on the anode. This side reaction results in a reduction of battery capacity and, in severe cases, can cause internal short circuits, posing safety risks. Therefore, preventing plating has become a major concern for fast charging. In this thesis, experimental data measurements are used to determine the plating current, and the relationship between plating current and constant current ( CC ) charging time is fitted. By calculating the point in CC time when the plating current is zero, plating can be effectively prevented. Additionally, the Butler-Volmer ( B-V ) equation is applied to calculate the plating overpotential using the obtained plating current. The study investigates side reactions in half-cells using full-cell information. Regarding charging strategy applications, the fitting results of experiments and plating current are used to achieve fast charging, aiming to reduce the constant current charging time without causing lithium plating. Furthermore, the study discusses the trends and causes of lithium plating formation in LIBs under different operating conditions, including charging speed (C-rate), state of health (SOH).