Under fast-charging or low-temperature charging conditions, large-format lithium-ion batteries are prone to inhomogeneous lithium plating, resulting in localized degradation and even internal short circuit, thus requiring a thorough investigation. This study establishes a three-dimensional electrochemical model to analyze the inhomogeneous lithium plating behavior in lithium-ion batteries. The model is validated with the voltage profiles and temperature distributions of a 24Ah pouch lithium-ion battery during low-temperature charging. The inhomogeneous lithium plating induced by non-uniform temperature distribution and the underlying mechanism are investigated using the model. The local current density and overpotential turn out to be the key factors affecting the spatial distribution of plated lithium. Moreover, the effects of temperature gradients on the lithium plating and stripping behaviors are explored. In-plane temperature gradient shows little effect on the total amount of plated lithium, but leads to apparent inhomogeneity in the distribution of plated lithium, with the differences between the concentrations of plated lithium in the upper and lower half of battery reach 57.61%, 103.06% and 159.68% of the average concentration in the whole battery during 1C charging at -5, 5 and 10°C, respectively. The temperature gradient also significantly influences the battery voltage relaxation profile related to the lithium stripping process. The characteristic plateau in the battery voltage relaxation profile disappears when the temperature gradient increases to larger than 6°C, leading to difficulty in detecting inhomogeneous lithium plating in large-format lithium batteries. The results presented in this study can provide helpful guidance for the design and management of large-format lithium-ion batteries.

在快速充电或低温充电条件下，大规格锂离子电池容易出现锂镀层不均匀，导致局部劣化甚至内部短路，需要深入研究。本研究建立了一个三维电化学模型来分析锂离子电池中的不均匀锂镀层行为。该模型通过 24Ah 软包锂离子电池在低温充电过程中的电压曲线和温度分布进行了验证。使用该模型研究了由非均匀温度分布引起的不均匀锂镀层及其潜在机制。局部电流密度和过电位是影响镀锂空间分布的关键因素。而且，探讨了温度梯度对锂电镀和剥离行为的影响。面内温度梯度对镀锂总量影响不大，但导致镀锂分布明显不均匀，电池上下半部镀锂浓度差异达到57.61%、103.06分别为-5、5、10℃下1C充电时整个电池平均浓度的%和159.68%。温度梯度也显着影响与锂剥离过程相关的电池电压弛豫曲线。当温度梯度增加到大于 6°C 时，电池电压松弛曲线中的特征平台消失，导致大尺寸锂电池中锂镀层不均匀的检测困难。本研究结果可为大型锂离子电池的设计和管理提供有益的指导。