A fast charging Multi-C technique for mobile devices

Users of mobile devices typically charge their devices over night. In these situations, it is acceptable to the users for the phone to take several hours to charge. But at times, such as when traveling, users want fast charging for their devices, and would like to have the battery maintain high charging capacity for an extended period without need to recharge. However, the battery's charging capacity diminishes after many charging and discharging cycles. At that point, the mobile device starts requiring more frequent charging, which becomes very disruptive for travelers. As a result, fast charging and maintaining battery quality and capacity retention over extended number of charging-discharging cycles is a valuable user experience for mobile device users. Traditional constant current constant voltage(CC-CV) charging methods require higher density batteries to be charged with lower charging current leading to long charging time up to 4.5 hrs - 5hrs. In this paper, we propose an alternative faster approach to battery charging based on multi-rate decisions without compromising battery longevity. Our experiments show that the battery charge time can be increased by ~ 3x, leading to 1.2hrs time needed to charge. The results also show that the battery can be charged beyond 100% rated capacity to almost 102.5% and still maintaining lower skin temperature.