This study focuses on the performance of solid electrochemical capacitors (ECs) after being subjected to a series of bending tests. A systematic approaching using cyclic voltammetry to track the electrodes and devices reveals the effects of bending parameters include angle, radius and number of cycles. For a single bending cycle, the bending angles from 90 degrees to 180 degrees has little effect on the performance of the solid EC cells. A small bending radius (e.g. < 5mm) increases the cell resistance as a result of delamination at the current collector/electrode interface. For repeated bending cycles, even a relatively small bending angle with a large radius causes soft shorting by the localized deformations at the electrolyte-separator film. Cross-sectional analyses with scanning electron microscopy support these notions and reveal the failure mechanism of these solid-state, thin and flexible ECs after bending. Although the approach is demonstrated on a sandwiched solid EC cell with a commercial activated carbon and a neutral pH polymer electrolyte, it can be extended to other solid-state, flexible, and wearable electrochemical devices. (C) The Author(s) 2019. Published by ECS.