On the efficacy of SoC-preconditioning on the utilization of battery packs in Electric Vehicles

2021 ◽  
pp. 103711
Author(s):  
Alexander Lamprecht ◽  
Ananth Garikapati ◽  
Swaminathan Narayanaswamy ◽  
Johannes Machleid ◽  
Sebastian Steinhorst
Author(s):  
Cody L. Telford ◽  
Robert H. Todd

Since the early 1900’s demand for fuel efficient vehicles has motivated the development of electric and hybrid electric vehicles. Unfortunately, some components used in these vehicles are expensive and complex. Todays consumer electric vehicles use dangerously high voltage, expensive electronic controllers, complex battery management systems and AC motors. The goal of this research at BYU is to increase safety by lowering the operating voltage and decrease cost by eliminating expensive controllers and decrease the number of battery cells. This paper specifically examines the use of a Ward Leonard Motor Control system for use in a passenger vehicle. The Ward Leonard System provides an alternative control method to expensive and complex systems used today. A Control Factor metric was developed as a result of this research to measure the Ward Leonard System’s ability to reduce the size and cost of the electronic controller for application in an EV or HEV. A bench top model of the Ward Leonard system was tested validating the Control Factor metric. The Ward Leonard system is capable of reducing the controller size by 77% and potentially reducing its cost by this amount or more. This work also provides performance characteristics for automotive designers and offers several design alternatives for EV and HEV architectures allowing a reduction in voltage, the use of AC inverters, AC motors, expensive controllers and high cell count battery packs.


2021 ◽  
Author(s):  
Steffen Schmidt

<p> There is a simple concept that can significantly improve the environmental balance of battery electric vehicles and at the same time avoid the known disadvantages of these vehicles (short range, long charging times, high acquisition costs) without having to wait for further developed batteries or a higher proportion of green electricity. For this purpose, the vehicles are equipped with built-in batteries for short and medium distances and are therefore sufficient for the majority of daily journeys. For long-distance journeys, the driver borrows charged additional battery packs at swapping stations, which are automatically inserted into a standardised exchange slot within a few minutes. This paper focuses on the improvements in electric vehicles that can be achieved by combining built-in and exchangeable battery technique and also on the practical feasibility of the concept. It is shown that the battery capacity required for the entire vehicle fleet can be significantly reduced. The resulting ecological advantages on the one hand and grid-stabilising effects of a nationwide network of swapping stations on the other hand, support the transition to environmentally sustainable mobility. The characteristics of the concept presented are advantageous for its practical implementation. The acceptance by customers and manufacturers can thus be improved compared to previous battery swapping systems. The loan system for the exchange batteries may be designed conveniently and information security as well as data protection will be strictly complied.</p>


Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4772 ◽  
Author(s):  
Kaizhi Liang ◽  
Zhaosheng Zhang ◽  
Peng Liu ◽  
Zhenpo Wang ◽  
Shangfeng Jiang

Accurate state-of-health (SOH) estimation for battery packs in electric vehicles (EVs) plays a pivotal role in preventing battery fault occurrence and extending their service life. In this paper, a novel internal ohmic resistance estimation method is proposed by combining electric circuit models and data-driven algorithms. Firstly, an improved recursive least squares (RLS) is used to estimate the internal ohmic resistance. Then, an automatic outlier identification method is presented to filter out the abnormal ohmic resistance estimated under different temperatures. Finally, the ohmic resistance estimation model is established based on the Extreme Gradient Boosting (XGBoost) regression algorithm and inputs of temperature and driving distance. The proposed model is examined based on test datasets. The root mean square errors (RMSEs) are less than 4 mΩ while the mean absolute percentage errors (MAPEs) are less than 6%. The results show that the proposed method is feasible and accurate, and can be implemented in real-world EVs.


Author(s):  
S. Shawn Lee ◽  
Tae H. Kim ◽  
S. Jack Hu ◽  
Wayne W. Cai ◽  
Jeffrey A. Abell

Automotive battery packs for electric vehicles (EV), hybrid electric vehicles (HEV), and plug-in hybrid electric vehicles (PHEV) typically consist of a large number of battery cells. These cells must be assembled together with robust mechanical and electrical joints. Joining of battery cells presents several challenges such as welding of highly conductive and dissimilar materials, multiple sheets joining, and varying material thickness combinations. In addition, different cell types and pack configurations have implications for battery joining methods. This paper provides a comprehensive review of joining technologies and processes for automotive lithium-ion battery manufacturing. It details the advantages and disadvantages of the joining technologies as related to battery manufacturing, including resistance welding, laser welding, ultrasonic welding and mechanical joining, and discusses corresponding manufacturing issues. Joining processes for electrode-to-tab, tab-to-tab (tab-to-bus bar), and module-to-module assembly are discussed with respect to cell types and pack configuration.


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