Bending and other applied forces like folding, stretching, and twisting substantially create mechanical deformation within the flexible battery components and at their junctions, which ,in turn, indirectly alter the atomic properties. As a result of both, the cyclic performance of the battery is negatively influenced. Rigorous research is going on to inhibit the effect of mechanical deformation, by choosing appropriate materials for active and inactive components of battery and by engineering the battery construction to ameliorate the surface and interfaces of the components. Consequently, novel and fancy flexible energy devices are coming in the market. However, the precise mechanistic study of the charge flow under mechanical force is mostly neglected in those reports. This article encourages to develop new techniques for the flexible lithium‐ion batteries (LIBs) beyond stress‐strain curve under bending operation. The principal interest is to bridge between mechanical changes and atomic changes developed inside the flexible battery, along with their mutual influence to each other. It is proposed from the miscellaneous articles that in situ visualization of crack and dislocation, simultaneous application of new generation and microstructure strain sensors, and simultaneous analysis of parameters related to charge transport (e.g., resistance and diffusion) can picturize the entire process holistically. This article summarizes lists of suitable instances of each category. Most of the instances are extracted from the rigid batteries where in situ and in operando analysis are performed. There are instances from materials other than energy devices like construction materials, where the fractures are more severe. Only those examples are picked where the mechanistic analyses can be applicable for the damages created in flexible batteries and the instrumentations are facile to be integrated in a flexible battery set up. In this regard, miniatured devices and miniatured detection tools are given importance. Significance of electrochemical impedance spectroscopy (EIS), along with fitting and modeling, is specially focused. The aim of the thorough mechanistic scrutiny is to create a pattern between the choice of materials and engineering the surface to cut short the trial and error for a suitable setup. In other words, a pattern between mechanical properties and atomic properties. This article is can be a guidebook of directing the future research on this field.
Maity et al. (Sun,) studied this question.