The pseudo-two-dimensional (P2D) electrochemical model can give insight into the internal behavior of lithium-ion batteries, which is of great significance for intelligent battery management. However, the computational complexity of the P2D model greatly limits its onboard application. This paper devotes to develop a reduced-order electrochemical model (ROEM) with high fidelity yet low computational cost. First, for the simplification of the electrolyte diffusion process in batteries, domain decomposition technique is applied to divide the whole cell sandwich into two computation domains. The polynomial approximation method is adopted to describe the electrolyte concentration distribution in each domain, so that the electrolyte diffusion process is represented by two independent state variables. Next, combining the simplified electrolyte diffusion process and other dynamics in lithium-ion batteries, the complete ROEM is obtained as a five-state diagonal system. Finally, the prediction accuracy of the ROEM on electrolyte concentration, electrolyte diffusion overpotential and terminal voltage is verified by comparing with the P2D model and experimental results. Moreover, the proposed ROEM has an ideal computing speed for real-time application, which is at least 600 times faster than the rigorous P2D model.

伪二维（P2D）电化学模型可以洞悉锂离子电池的内部行为，这对于智能电池管理具有重要意义。但是，P2D模型的计算复杂性极大地限制了其车载应用。本文致力于开发具有高保真度但计算成本较低的降阶电化学模型（ROEM）。首先，为了简化电池中的电解质扩散过程，应用域分解技术将整个电池夹层划分为两个计算域。采用多项式逼近法描述每个域中的电解质浓度分布，从而使电解质的扩散过程由两个独立的状态变量表示。下一个，结合简化的电解质扩散过程和锂离子电池的其他动力学特性，可获得完整的ROEM作为五态对角线系统。最后，通过与P2D模型和实验结果的比较，验证了ROEM对电解质浓度，电解质扩散超电势和端电压的预测准确性。此外，所提出的ROEM对于实时应用具有理想的计算速度，其速度至少比严格的P2D模型快600倍。