Abstract
In this work, an experimental approach to reduce the variation from cell to cell during battery operation is evaluated to reach a better battery utilization. Numerous theoretical considerations of intelligent battery management systems without long-term experimental validation of their capabilities lead to a gap in the literature, which this work aims to address. For this purpose, the ageing behaviour of two batteries is investigated for almost 1.5 years. One battery is connected to an active balancing battery management system (BMS) and the other to a conventional passive balancing BMS. Important battery parameters, such as capacity and internal resistance, are recorded in each cycle. The battery behaviour is evaluated in detail by observing the voltage difference of the individual cells at the end of discharge and by calculating the amount of charge balanced by the BMS. Significant differences between the BMS systems used are elucidated, which illustrate the advantages of active balancing. In contrast to passive balancing, active balancing can reduce the ageing rate of the battery and achieve better utilization with a more than five times lower voltage spread at end of discharge, a up to 3.1% higher discharge capacity and a 7.7% longer service life.
Highlights
Due to the rising CO2 concentration in the atmosphere and the associated climate change, the emission of climate-active gases must be significantly reduced in the future in order to keep global warming below the targeted 2 ◦C limit [1]
The results show that calendar ageing is fastest at low anode potentials and high temperatures
By considering the voltage differences of the individual cells in each cycle, it becomes clear that the active balancing system in this specific test can achieve a voltage difference up to 5 times smaller compared to the passive balancing system
Summary
Due to the rising CO2 concentration in the atmosphere and the associated climate change, the emission of climate-active gases must be significantly reduced in the future in order to keep global warming below the targeted 2 ◦C limit [1]. In the transport sector, a rapidly developing electrification of vehicles is taking place, which results in rapid growth for the production of lithium-ion batteries [2]. Lithium-ion batteries are the best compromise in terms of their energy and power density. They have been continuously improved and further developed over the past decades [3]. They are most suitable for electrifying the transport sector. China and the USA have seen an enormous increase in battery electric vehicles. In the USA, sales of battery-powered vehicles tripled from 2015 to 2019, in China even quadrupled [4].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
