Research on State of Charge Estimation of Batteries Used in Electric Vehicle

Abstract

SOC (State Of Charge) was one of the most important parameters for EVs (Electric Vehicles). It was the basis for EVs to prevent over-charging and over-discharging. Many researchers had been done to improve SOC estimation accuracy. In this paper, definition of SOC was discussed and the traditional SOC estimating algorithms and some improved SOC estimation algorithms were reviewed. The principles of these methods were also been introduced. By comparing their advantages and disadvantages of these methods, proposed a new idea of SOC estimation. This method would make SOC estimating accurate and simple.

Online impedance spectroscopy estimation of a battery

“…Offline Impedance estimation [9]- [10] It uses the impedance spectrum of the battery to produce an impedance model (equivalent circuit) to estimate the circuit parameters. The variation of these under different condition used to estimate the SOC of the battery.…”

“…Online AC internal resistance [10] - [14] As small current ripple is used to measure internal impedance at a fixed frequency point to provide a value of impedance. The battery SOC is estimated using the measured internal impedance.…”

Design of a Shape File Index for Fast Map Matching in Electric Vehicle Services

“…Besides the classic control objects such as brake control modules, the ECU is required to deal with battery devices in cooperation with the BMS. The BMS is the most important part in EVs, as the battery is the engine of EVs [13]. The BMS prevents every cell in the battery from being overcharged or undercharged.…”

Comparative Study on SOC Estimation Techniques for Optimal Battery Sizing for Hybrid Vehicles

“…In addition to the immediate display of the remaining battery capacity to the user, precise knowledge of SOC exerts additional control over the charging/discharging process, which can be employed to increase battery life [3]. Some studies have presented a state of charge (SOC) and a state of health (SOH) estimation method for batteries [2] by explaining the measurements of battery's terminal voltage, current and temperature that are used in the process of SOC calculation.…”