动力锂电池正极涂布快速制造中粘合剂分布均匀性调控及能耗优化研究

In the coated web of positive electrode production, the slow and high energy consumption of the drying process greatly restricts the shortening of the production cycle of the automotive lithium battery and the improvement of energy efficiency. However, simply accelerating the drying process will cause heterogeneous distribution of the binder within the web, which seriously impairs the electrode performance. Therefore, this research project proposes the development of collaborative design between dynamic drying and calendering parameters, to reduce the average drying time of the coated web, while regulating the distribution status of binder as well as optimizing energy consumption. 1. Analyze the mass transfer process in wet web drying, and calculate the evaporation rate under different drying parameters. 2. Elucidate the inter-layer transport mechanism of binder, develop the binder transport equation, and determine the binder distribution at the different evaporation rates; Analyze the influence of the binder concentration on the compression modulus of the dry web, and quantify the adjustment of the calendaring pressure to the binder distribution. 3. Construct a parameterized energy consumption model to predict the energy consumption of the drying process. 4. Divide the dynamic drying section according to the stage characteristics of binder migration. Finally, the multi-objective optimization algorithm is combined with the multi-dimensional decision strategy to solve the collaborative design scheme of dynamic drying and calendering parameters. The results of this project will help overcoming the bottleneck of battery performance deterioration caused by the increase in production speed of coated web of the positive electrode, help reducing costs of the battery production, and promote the green development of the lithium-ion battery industry.

在正极涂布制造过程中，缓慢且高耗能的干燥环节极大地制约了动力锂电池生产周期缩短及能效提升。但一味简单地加快干燥速度，将导致粘合剂在涂布层间的分布不均匀，严重损害电极性能。为缩短涂布干燥时间、调控粘合剂的浓度分布状态并降低能耗，本研究拟发展前端动态干燥与后端辊压压力匹配的正极涂布制造方法。①分析涂布中溶剂的蒸发传质过程，定量阐述蒸发速率的影响因素，明确干燥时间计算方法。②阐明粘合剂的迁移机制，构建层间输运方程，计算不同蒸发速率下的粘合剂浓度分布；揭示粘合剂含量对涂布压缩模量的影响规律，量化辊压对粘合剂分布的调整。③构建参数化的能耗模型，预测干燥过程耗能。④根据粘合剂迁移的阶段性特征，划分动态干燥区段，使用多目标优化算法结合多维决策策略，求解动态干燥及辊压模式的协同设计方案。本课题的成果有助于克服因涂布生产速度提升造成电池性能恶化的技术瓶颈，降低生产成本，推进动力锂电池产业的绿色发展。

在正极涂布制造过程中，缓慢且高耗能的干燥环节极大地制约了动力锂电池生产周期缩短及能效提升。但一味简单地加快干燥速度，将导致粘合剂在涂布层间的分布不均匀，严重损害电极性能。为了优化正极涂布制造过程，本研究针对NMP蒸发，PVDF粘合剂层间输运，供热设备能耗建模，以及供热设备控制与风机效率优化进行了全面的研究工作。.1.分析了涂布中溶剂的蒸发传质过程：提出了多孔电极蒸发的两阶段理论，提出分析第一阶段为NMP蒸发的主要过程，明确了NMP蒸发速率的明确计算公式和干燥时间的计算方法。.2.分析了PVDF粘合剂的层间输运过程：采用RVE代表性体积单元的方法构建了PVDF的层间输运方程，并实现了数值求解，分析指出当蒸发速率不超过10^-16 m/s时粘合剂的浓度分布较为均匀。.3.分析了辊压过程对不同容量配比(N/P)的影响：研究结果指出，当把不同N/P配比的正负极辊压到同一厚度下时，研究N/P越高克容量密度越高，但是过量的辊压造成衰减过快，N/P=1.14时辊压后电极容量衰减最快。.4.优化大型离心式风机：搭建了离心式风机优化实验平台，首先采用实验验证了数值模拟计算的准确性，然后用稳态数值模拟计算构建了包含48个样本的样本库，采用BP神经网络和粒子群算法对其进行寻优，从而提出风机设计的优化方案，优化后风机静压提高58Pa,静压效率提高1.4%。.5.构建供热地源热泵系统的能耗模型与闭环模型预测控制方法: 研究发现通风侧变量会显著的改变热泵运行效率，同时不同供水温度对于地源热泵影响呈非线性，因此研究采用了高斯过程回归来拟合能效比与供水温度和送风量的关系。实验过程中，最低能效比为1.7而最高能效比高达为6.7，均偏离额定能效比。因此地源热泵的通风侧变量会明显改变地源热泵的运行状态，导致地源热泵的效率变化。基于高斯过程回归获得的模拟数据，进一步用多项式进行拟合获得热泵能效的精确预测公式，误差小于0.2%。通过合理配置通风侧变量可以在不明显改变热效果的前提下，提高地源热泵系统的运行效率，实现节能。通过模型预测控制最高可降低20%的热泵能耗。

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