Optimization of Battery Capacity Decay for Semi-Active Hybrid Energy Storage System Equipped on Electric City Bus

Abstract

Abstract:In view of severe changes in temperature during different seasons in cold areas of northern China, the decay of battery capacity of electric vehicles poses a problem. This paper uses an electric bus power system with semi-active hybrid energy storage system (HESS) as the research object and proposes a convex power distribution strategy to optimize the battery current that represents degradation of battery capacity based on the analysis of semi-empirical LiFePO 4 battery life decline model. Simulation results show that, at a room temperature of 25 • C, during a daily trip organized by the Harbin City Driving Cycle including four cycle lines and four charging phases, the percentage of battery degradation was 9.6 × 10 −3 %. According to the average temperature of different months in Harbin, the percentage of battery degradation of the power distribution strategy proposed in this paper is 3.15% in one year; the electric bus can operate for 6.4 years until its capacity reduces to 80% of its initial value, and it can operate for 0.51 year more than the rule-based power distribution strategy.

Development Forecasts for the Zero-Emission Bus Fleet in Servicing Public Transport in Chosen EU Member Countries

“…Bus demand for electricity depends on battery type, driving cycle and style, number of stops, traffic level, elevation profile [69,70], and weather conditions including temperature and humidity [8]. In order to improve the driving style, and thus reduce the bus's energy demand, various technological solutions are proposed, for example, the robotized manual gearbox [56,71,72]. Cost effectiveness also varies depending on the energy storage systems in electric buses [71,73] and the choice of charging technology [74].…”

“…In order to improve the driving style, and thus reduce the bus's energy demand, various technological solutions are proposed, for example, the robotized manual gearbox [56,71,72]. Cost effectiveness also varies depending on the energy storage systems in electric buses [71,73] and the choice of charging technology [74]. Operating costs also depend on the price of the battery and the battery life [75].…”

Studies of Energy Consumption by a City Bus Powered by a Hybrid Energy Storage System in Variable Road Conditions

“…Initial research was related to the analysis of properties and the possibility of using mainly hybrid propulsion systems [6][7][8][9][10] in city buses using internal combustion engines in series [11] or parallel 2 of 39 layouts [12] as well as hydraulic drive [13] and CNG powered systems [14]. With the introduction of increasingly restrictive emissions standards for road transport, technological solutions based on purely battery drive systems [15] and their variants using hybrid battery-capacitors systems [16][17][18][19], replaceable energy store systems [20,21] or range extenders [22] are sought. In addition to the mentioned technologies, research related to the use of photovoltaic panels [23] or hydrogen fuel cells [24,25] for city electric buses was conducted.…”

Advanced Energy Storage Technologies and Their Applications (AESA2017)

“…(1) China (18). The lithium-ion battery has been investigated broadly, including equivalent circuit modeling and parameter estimation [3,4], state of charge and peak power estimation [5,6], battery pack equalization [7], and battery capacity decay [8]. Recently, battery heating-related characteristics have been a research focus.…”