大型动力电池单体及系统设计方法研究

The battery in electric vehicles is large-format in the cell and the system level. The demand for its electrical, thermal, lifespan and safety performance is correspondingly higher. Battery design in both levels is important in performance improvement and most of the existing literature depicts the design work for a certain type of performance and lacks the study of common methods. This study intends to study the methods of the cell and system design and establish a method platform linking through different design tasks. In terms of method structure, two key questions are tried to be answered: what are the essential difference in the design methods for the above four kinds of performance, and what are the essential difference between methods for cell and system design. In terms of particular methods, ① proposing the "structure-activity relationship modeling" as the featured design method for the electrical and thermal performance. Based on the previous work on non-volume-averaging electrode model and high-precision thermal model, trying to make breakthroughs in modeling complex manufacturing technology; ② proposing the "element experiment" as the featured design method for the performance on lifespan and safety, including the orthogonal experiment method for reducing the combined number of all experimental sets and the accelerated experimental method for reducing the time cost in one single experimental set. ③ proposing two specific methods for system design, including the statistical method involving the cell-to-cell inconsistency and the model simplification method controlling the multiplication of calculation in system simulation. The study could solve the fundamental scientific problems such as physical modeling and mathematical equation solution and generates some methods as well as tools for the traction battery design.

电动汽车电池在单体、系统两个层次都具有“大型化”的特点，对其电、热、寿命、安全性提出了更高要求。单体与系统设计是提升性能的重要途径，现有文献多针对某类性能开展具体设计，缺少共性方法研究。本项目拟研究电池单体与系统的设计方法，建立横向方法平台。在方法结构上，回答“四类性能的设计方法、系统与单体的设计方法有何本质区别”两个关键问题。在具体方法上，①提出以“构效关系建模”为特征的电/热性能设计方法，在非体积平均电极模型与高精度热模型的研究基础上，重点突破复杂工艺的模型化表征难题；②提出以“因素实验”为特征的寿命/安全性能设计方法，重点研究面向电池设计的正交实验方法、加速实验方法；③提出系统设计的两类特有方法，纳入单体不一致性对系统影响的统计学方法、控制系统计算量倍增的单体模型简化方法。研究可解决电池设计中与物理建模与数学求解相关的关键科学问题，形成服务于动力电池设计的方法与工具。

在中国动力电池产业进入产能建设绝对过剩、高质量发展迫在眉睫的重要历史转折点，本项目建立动力电池设计理论、探索动力电池设计方法、孵化动力电池设计工具，对于提高我国动力电池的核心研发能力、促使产业由生产要素驱动向技术能力驱动转型发挥了并仍将继续发挥重要的作用。.按照项目计划书的要求，我们依次完成了如下4类具体研究内容：（1）电池多尺度多物理场构效关系建模，尺度跨越10^5量级，场包含电化学、化学、热、应力；（2）电池模型所需的一揽子参数的测定与参数库建立；（3）基于上述模型与参数，构建了电池设计专用的数值求解器，解决了多场耦合、高质量网格、求解器底层自主化、高稳定性与高效率数值解算四类主要问题；（4）完成了多款电池单体与系统的典型设计案例，部分设计型号实现了规模量产。.面向电池这一多组分部件、多物理化学过程的复杂对象，本项目成功实现了构效关系建模，并证实了模型对于电池产品设计问题具有普遍的高精度和实用性。这一能力的建立使得电池型号设计过程脱离了早期的实验试错方法，迈入了正向设计方法的新阶段，在产品质量、开发效率、开发成本三个方向获得了显著收益，其中尤以2~5倍左右的开发效率提升最具代表性。