PHM of state-of-charge for flexible power sources in wearable electronics with EKF

摘要

Combined effects of distinct bending load(s) and operating temperatures can significantly attenuate the life of flexible Li-Ion batteries in foldable wearable electronics. Present day technologies call for battery applications, which require exposure to bending stresses, human body and varying ambient temperatures. Current health monitoring techniques and test standards for flexible power sources are still in the nascent stages. Flexible power sources such as Li-Ion batteries may undergo multiple charge-discharge cycles during operation, therefore development of a hardware testbed, which mimics the operating conditions in their areas of applications, is needed. In this research study, the combined effects of distinct bending load(s) and operating temperatures have been characterized for Li-Ion batteries. Battery cells were cycled through multiple charge-discharge cycles under simultaneous bending loads plus thermal stresses and output parameters such as efficiency, power, capacity and charge-discharge time have been analyzed for battery state assessment. State-of-the-art Li-Ion batteries have been tested under multiple operating temperatures of 50°C, 25°C, and 0°C combined with distinct bending loads which are imposed only during the discharge cycles in order to replicate real world applications. The hardware testbed takes battery measurements at regular intervals and enables cells to be in either the charge or discharge regime. The main goal of this research study is to observe and document the survivability of Li-Ion batteries when subjected to simultaneous distinct ambient temperatures and bending loads in foldable electronics as function of the above mentioned battery parameters.