Novel beads-and-thread structural designs have been applied in the new-generation flexible lithium-ion batteries (LIBs) to achieve high electrochemical performance and high flexibility simultaneously. However, to understand the mechanical degradation and to obtain the best performance of these flexible LIBs, the structural analysis and design of such LIBs are of crucial importance. Accordingly, it is necessary to establish detailed and systematic analytic and simulation models to describe the mechanical behavior of these LIBs. Here, the flexibility, energy density, and safety criterion of beads-and-thread LIBs are quantitatively discussed by an analytic finite deformation model and a finite element analysis (FEA) model. The trade-off between effective flexibility and relative energy density of LIBs has been discussed with the parametrical study of two key geometric parameters, length ratio and winding layer number of the structural element. Stress/strain analysis reveals the yield of the Al foil layer in unwound part could be a safe criterion for evaluating mechanical degradation of the battery. Rational design diagrams of flexibility and relative energy density are investigated for the battery designers, considering the balance of battery safety, mechanical and energy storage properties. This work is expected to provide the design guidelines for flexible beads-and-thread LIBs.

新一代的柔性锂离子电池（LIB）已采用新颖的珠线结构设计，以同时实现高电化学性能和高柔性。但是，要了解这些柔性LIB的机械性能并获得最佳性能，此类LIB的结构分析和设计至关重要。因此，有必要建立详细而系统的分析和仿真模型来描述这些LIB的机械性能。在此，通过解析有限变形模型和有限元分析（FEA）模型定量地讨论了串珠LIB的柔韧性，能量密度和安全性准则。通过对两个关键几何参数（长度比和结构元件的缠绕层数）的参数研究，讨论了LIB的有效柔韧性和相对能量密度之间的取舍。应力/应变分析表明，未缠绕部分的铝箔层屈服可能是评估电池机械性能的安全标准。考虑到电池安全性，机械性能和储能性能之间的平衡，为电池设计人员研究了柔韧性和相对能量密度的合理设计图。预期这项工作将为柔性珠和线LIB提供设计指南。应力/应变分析表明，未缠绕部分的铝箔层屈服可能是评估电池机械性能的安全标准。考虑到电池安全性，机械性能和储能性能之间的平衡，为电池设计人员研究了柔韧性和相对能量密度的合理设计图。预期这项工作将为柔性珠和线LIB提供设计指南。应力/应变分析表明，未缠绕部分的铝箔层屈服可能是评估电池机械性能的安全标准。考虑到电池安全性，机械性能和储能性能之间的平衡，为电池设计人员研究了柔韧性和相对能量密度的合理设计图。预期这项工作将为柔性珠和线LIB提供设计指南。