Articles techniques et présentations

对锂离子电池进行准确建模有利于更好的进行电池设计和电池管理。目前对电池电化学模型的建立主要是基于传统的P2D理论，将活性颗粒假设为均匀分布的球形，使用bruggman关系式近似计算固液相的有效传输参数并忽略了粒径和孔隙率在电极内的异质性分布。在小倍率充放电条件下由于锂离子浓度梯度较小，所以均质化模型可以准确表达电池的内外特性；然而在大倍率条件下，厚度方向上复杂异质性的孔隙限制了锂离子的传输，特别是对于厚电极。此时均质化模型往往低估了电池极化，导致仿真与实验结果误差大，模型不准确。为了充分考虑电极结构的异质性，本研究在传统P2D模型的理论框架下，将电极厚度方向分为多层 ... En savoir plus

随着锂离子电池能量密度的不断提高，电池热安全问题日趋严峻。本研究基于电池热失控反应动力学模型和相变传热模型，结合电池与复合相变材料（compose phase change materail CPCM: paraffin/ expanded graphite PA/EG）间的传热规律，建立了一个二维数值计算模型，利用COMSOL Multiphysics软件进行多物理场建模与求解（图1）。首先，通过拟合产热率与温度变化的关系，构建了电池热失控模型。模型通过调整CPCM的物性参数（相变焓与导热系数），探索其对热失控传播的影响。为了确保计算精度，本研究进行了网格无关性验证 ... En savoir plus

In the development of advanced welding torches, a significant challenge lies in optimizing design and performance while minimizing costs and environmental impact. Traditionally, this has involved extensive physical testing, which is both time-consuming and resource-intensive. To address ... En savoir plus

The low-temperature electrochemical conversion of CO₂ to ethylene offers significant potential for reducing the chemical industry’s reliance on fossil fuels. Despite recent advancements, the key performance indicators—activity, selectivity, and durability—are insufficient for industrial ... En savoir plus

Beams-driven structures are structures that use beams to support their weight. The beams are typically arranged in a way that distributes the weight of the structure evenly. Beams-driven structures are often used in buildings, bridges, and other complicated structures. Beams-driven ... En savoir plus

In this conference we have brought together a community that is scientifically diverse in an event that allows for inspiring contacts about the use of COMSOL Multiphysics. It is an event to connect with the Spanish and Portuguese COMSOL Multiphysics users and participate in training ... En savoir plus

为了证明膨胀对电池厚度变化的影响，传统p2d模型耦合移动边界法新建立了一个模型。对复合材料的比例进行了详细分类，以准确分析两种材料对容量的贡献。此外，还研究了电极设计（如活性层厚度和负极孔隙率）以及工作条件对电池电化学性能和厚度变化的影响。当硅含量增加并改变电极结构时，容量贡献率从 85% 增加到 92%。当孔隙率从 40% 增加到 60% 以及负极活性层厚度从 55 μm 增加到 85 μm 时，容量利用率分别从 58% 到 79% 和从 68% 到 59% 不等。在速率测试中，当速率从 0.5 C 变化到 2 C 时，电池厚度变化从 2.49 μm 减小到 1.56 ... En savoir plus

Problem - The occlusion effect is an increase in loudness (sound pressure level) of your internal voice, especially in the low frequency range. Also, self-generated sounds such as chewing, swallowing, walking or running are amplified when the ears are blocked or occluded. Occlusion ... En savoir plus

Structural Supercapacitors (SSC) are an important group of Multifunctional Energy Storage Composites (MESC) and can potentially play a significant role in lightweight design of aerospace and automotive applications [1]. Therefore, it is important to build accurate models based on the ... En savoir plus

The temperature distributions inside two packs (in-line and staggered) made of large cylindrical lithium iron phosphate cells (of 18 Ah nominal capacity) are analysed in this paper during a 90 A constant discharge current. The analysis of the battery packs temperature distributions is ... En savoir plus