半固态锂电池的反应动力学建模与应用

The semi-solid lithium battery (SSLB) is a new type of energy storage battery technology proposed in recent years, and it is thought to have a good application prospect in the fields of smart grid, electric vehicle, household energy storage system, etc. However, at present it is still within the stage of basic principle and key technology research. Modeling of reaction kinetics is essential for the guiding of optimal design and developing of key technology of the battery. However, so far the modeling of the whole reaction kinetics of SSLB has not been established. In the present work, the microstructure evolution of the electrode slurry, and the relationship between the size of the active materials, the composition of the slurry, the concentration of the electrolyte, the settling velocity and the conductive stability of the electrode slurry will be investigated based on the percolation conductivity model together with various characterization methods. Then, taking the electrochemical potential gradient as the driving force of lithium diffusion, and combined with the new solid diffusion theory, the relationship between the parameters of battery materials and structures will be established. Through computer simulation and experimental validation, the controlling steps of the electrochemical reactions at different charge/discharge rate will be analyzed, and special attention will be focused on the influences of the main characteristic parameters of solid electrolyte interface on cell polarization and attenuation. Finally, the former results will be used for the modified preparation of the electrode slurry and the optimal design of battery reactors.

半固态锂电池是近年来开发的一种新型储能电池技术，在智能电网、电动汽车、家用储能等领域有很好的应用前景，但目前仍处于基础原理研究和关键技术开发阶段。电池的反应动力学建模对于指导电池优化设计和关键技术开发至关重要，但迄今为止描述半固态锂电池完整反应动力学过程的理论模型还没有被建立。本课题将首先在逾渗导电模型的基础上，结合多种表征手段，研究复合电极的微观结构演化规律以及复合电极颗粒大小、组成、浓度以及颗粒沉降速度与电极浆料导电稳定性之间的关系，并以电化学势梯度为出发点，结合最新的固体互扩散理论，建立电池各材料和结构参数与电池电化学性能之间的模型关系，通过计算机仿真模拟和实验验证，研究不同充放电倍率下电池电化学反应的控制步骤，重点分析固体电解质膜的主要特征参数对电池极化和衰减性能的影响规律，指导半固态锂电池电极浆料的改性制备和电池反应器结构的优化设计。

半固态锂电池（锂浆料电池）是一种低成本、高安全、易回收的新型电化学储能技术，本项目针对其特点，从电极浆料的悬浮导电性及微观结构演化规律研究、电池电化学动力学过程分析与建模仿真以及电池极化分析及性能优化设计三个方面开展工作。代表性成果如下：（1）获得了电极浆料的悬浮导电特性、锂离子扩散系数和固体电解质膜（SEI膜）阻抗随浆料固含量以及电压、电流的变化关系；（2）建立了耦合电极浆料导电扩散模型、集流内阻解耦结构模型和SEI膜半经验生长模型的电池电化学动力学模型框架，模拟了不同电池材料及结构参数对电池性能的影响；（3）结合集流体表面改性和不同的充放电机制，揭示了集流体表面特性对电池极化的影响及不同电流下的电池极化内阻变化规律，指导不同容量等级的电池性能优化设计。在项目执行期间，发表相关学术论文6篇（其中SCI收录2篇，EI收录1篇），申请国家发明专利2项，培养在读及毕业研究生3名。相关研究结果为锂浆料电池的关键技术开发和产品研制提供了重要的理论基础，目前团队第一代锂浆料电池中试产品已在太阳能路灯系统和低速电动车系统中开展了成功的测试应用。