Considerations for a power line communication system for traction batteries

Electric vehicles (EVs) are without a doubt one of the hottest topics of our time because of their advantages over combustion engine vehicles. This has persuaded many developers to try improving EVs so they will be more reliable and cheaper and as a result suitable for a broader range of consumers.In this paper we dive into the proper way of measuring and understanding the impedance of one prismatic cell from 100 kHz up to 1 GHz. Some common measurement mistakes and important points to notice are also explained. The effect of a power bar is shown as well. In order to make sure of the accuracy and the consistency of the measurements, they are compared with finite element simulations as well as with mathematical calculations.Investigations of conducted emissions are also of key importance since it has a direct influence on selecting a suitable frequency range. Accordingly, a thorough lab measurement is conducted to see the distortion harmonics and their influence on the carrier frequency. This knowledge can then be used to implement the power line communication (PLC) method.The PLC technique helps us to reduce the wire harness of a battery pack by using the existing high-voltage lines of the vehicle as the main transmission channel. This leads to cheaper battery packs by reducing the amount of used material for the wire harness and production time as well as assembly complexity.

Thermal Modelling of a Prismatic Lithium-Ion Cell in a Battery Electric Vehicle Environment: Influences of the Experimental Validation Setup

In electric vehicles with lithium-ion battery systems, the temperature of the battery cells has a great impact on performance, safety, and lifetime. Therefore, developing thermal models of lithium-ion batteries to predict and investigate the temperature development and its impact is crucial. Commonly, models are validated with experimental data to ensure correct model behaviour. However, influences of experimental setups or comprehensive validation concepts are often not considered, especially for the use case of prismatic cells in a battery electric vehicle. In this work, a 3D electro–thermal model is developed and experimentally validated to predict the cell’s temperature behaviour for a single prismatic cell under battery electric vehicle (BEV) boundary conditions. One focus is on the development of a single cell’s experimental setup and the investigation of the commonly neglected influences of an experimental setup on the cell’s thermal behaviour. Furthermore, a detailed validation is performed for the laboratory BEV scenario for spatially resolved temperatures and heat generation. For validation, static and dynamic loads are considered as well as the detected experimental influences. The validated model is used to predict the temperature within the cell in the BEV application for constant current and Worldwide harmonized Light vehicles Test Procedure (WLTP) load profile.