An aging-aware battery charge scheme for mobile devices exploiting plug-in time patterns

Abstract

The aging of a rechargeable battery is mainly due to stress during charge-discharge cycles. Although the discharge phase is difficult to control, the charging phase can be performed in a specific way in order to mitigate the aging of the battery during its usage. It therefore becomes important to select the correct charging algorithm. In the case of mobile systems, equipped mainly with lithiumion batteries, the standard widely adopted for charging a battery is the typical constant current/constant voltage (CC-CV) protocol usually based on a linearly regular charge process. In this work, we propose a charging protocol based on the standard CC-CV method in which the charge start time and the value of the charging current can be programmed in such a way that the aging of the battery is mitigated. To validate this charging scheme we use an aging model that includes the charge/discharge current among the major parameters, and an analytical macro-model for the CC-CV charge time analysis.

Intelligent Chargers Will Make Mobile Devices Live Longer

“…Several prior studies have dwelt on battery-health-aware charging [2], [3], [4], [5], [6]. However, commercial solutions are not yet mature.…”

“…Control knobs presented in related literature that mitigate battery aging during the charging process are (i) delayed charging [2] also in combination with (ii) reduced charging current [4], [5] and (iii) voltage relaxation periods [6]. So far a joint optimization of delay length, charge current, charge duration and voltage relaxation phase length has not yet been proposed.…”

Aging and Cost Optimal Residential Charging for Plug-In EVs

“…Charge/Discharge current is usually measured in C-rate, a current normalized to the one necessary to charge/discharge the nominal battery capacity in one hour. Aging increases with higher charge/discharge currents [10]. Various aging-aware charging protocols have been proposed in the recent years (e.g., [9]).…”

“…Functions f i are typically empirically fitted to measured data to determine their actual expression. With respect to [11], we consider the extended model with two extra factors f i relative to charge and discharge currents [10]. The total normalized capacity loss L (0 = no loss, 1 = no capacity available) after M cycles is then simply obtained by summing over the M cycles, i.e., L = � M m=1 L m .…”

A Temperature-Aware Battery Cycle Life Model for Different Battery Chemistries

“…In fact, various datasheets report a different cycle life for different charge/discharge currents. For this reason, the authors in [27] proposed an extended version of Millner's aging model [5] by including both charge/discharge C-rates with their related coefficients, as extracted from the manufacturer's data for a commercial LiFePO 4 battery. So, with respect to the aforementioned expression reported in (9), [15] provides a similar Arrhenius-type equation that includes the current rate (for values greater than C/2), here rewritten as follows:…”