Study on Battery Charging Strategy of Electric Vehicles Considering Battery Capacity

Abstract

This paper proposes an improved fast charging strategy for electric vehicles (EVs) by considering available battery capacity. According to previous research and battery experiment reports, the energy capacity of batteries is not fixed, and it can decrease temporarily depending on the magnitude of charging or discharging power. This paper addresses the decreased capacity in proportion to the magnitude of the charging power which leads to a reduction in the driving range. For effective and practical use for EV users, the change in battery capacity is expressed through an equation, and a new state of charged indicator is proposed. To improve the conventional charging method that uniformly supplies power regardless of the battery capacity, this paper proposes an optimal charging strategy injecting constant power. The proposed charging strategy provides an optimal charging power reference to minimize costs considering charged energy, charging time, and usable energy loss based on billing system of EV charging. To verify the effectiveness of the proposed charging method, the optimal charging power reference for each battery is calculated based on capacity and characteristics, and the total cost is compared. The results show that the performance of the proposed charging strategy is effective in minimizing both the reduced battery capacity and economic burden on EV users.

Sizing battery energy storage and PV system in an extreme fast charging station considering uncertainties and battery degradation

“…In the CPCV charging protocol, the EV battery is charged with a constant power in the CP mode until it reaches the cut-off voltage, after which the mode switches to CV mode wherein the voltage is held constant and charging power decreases [70]. The CPCV charging protocol is reported to have lower usable energy loss, higher charging efficiency, and lower cycle life aging of batteries especially in the case of fast charging (i.e., charging power > 50kW) [70][71][72]. The total energy demand profile of the XFCS is the aggregated charging energies of all the EVs served at the station on a typical weekday/weekend day and is given by ( 9):…”

Full‐state discrete‐time model‐based stability analysis and parameter design of dual active bridge converter in energy storage system

“…In the field of power electronics, the state of oscillation is considered to be an unstable state. According to the Jacobian matrix of the DAB converter, the Floquet multipliers can be easily obtained by (28), which determines the stability of the system and the phenomena of oscillation type.…”

“…Compared with CC and CP charging modes, the CV charging mode has larger stability boundaries of V 1 . Therefore, it is important for the DAB FIGURE 28 Inductor current waveform at steady state converter working in CC and CP mode to design appropriate k p when there is fluctuation of V 1 . 6.…”

“…In the charging process of the ESS, the DAB converter could be operating in CC charging mode firstly, in this process the battery voltage gradually increases. When the battery voltage increases to a certain range, CP charging mode is introduced in order to reduce the capacity of charging converter [28]. In this process, the battery voltage continues to rise.…”

Proposed Ranked Strategy for Technical and Economical Enhancement of EVs Charging With High Penetration Level

“…EVs have been the focus of many recent research studies in the last decade [2]- [22]. These studies discussed different essential topics such as EV charging/discharging [2]- [17], battery efficiency improvement [18]- [20], and charging cost reduction [21]- [23] as presented in Fig. 1.…”