Motivation

The aim of the IntLiIon project ("Intelligent data bus concepts for lithium-ion batteries in electric and hybrid vehicles") is to significantly increase the performance, safety and service life of electric and hybrid vehicles through intelligent battery management. The project participants are Bosch, KIT, ProDesign and Hanover University of Applied Sciences.

Problem definition

The current data communication systems of Li-ion batteries have so far been implemented using standard bus systems (e.g. CAN bus) and use additional cabling for this purpose. The consequences of this are higher costs, higher weight and complex production.
The maximum data rate of these protocols also sets a limit for the development of a new type of battery management system, because a higher data rate will be required for the increasingly complex sensors.

Wireless, i.e. radio-based data transmission as a planned solution

The aim is to develop novel data transmission systems for monitoring and controlling each of the approximately 100 cells of a battery pack without additional cabling and with a higher bandwidth than current systems. This should enable all cells to be monitored with a latency of a few milliseconds.

KIT is working on the design of a broadband, interference-resistant communication system for lithium-ion batteries. A wireless, i.e. radio-based data transmission based on the physical layer is one of two alternatives being researched at KIT. This novel approach consists of the use of antennas in the battery control unit and at each individual cell for communication between them within the traction battery. This requires knowledge of the channel properties, which must be investigated. For this purpose, the radio communication channel in the battery is investigated with different types of antennas and operating frequencies. This is a complicated scenario for radio communication due to the presence of many metallic and reflective objects (cells, connectors, battery housing, etc.) in the immediate vicinity of the antennas. This significantly modifies the antenna characteristics, depending on their position in the housing, the topology and the dimension of the battery. Another problem of the metallic environment is that multipath reception is caused by powerful reflections.

For these reasons, the choice of an antenna that can be used at different positions within the battery housing is of great importance, as well as the design of a robust communication system with cognitive capabilities, i.e. an autonomous adaptation to the respective environmental conditions.

Methodology

Investigation of wave propagation and antenna behaviour within the traction battery

• Selection of antennas and characterisation of the radio channel
• Selection of transmission parameters and system simulation.
• Development of a robust communication system: (physical and MAC layer)
• Use of cognitive technologies
• Development with Rapid Prototyping Platforms
• Validation in the vehicle

You can obtain further information from the following link: http://www.iiit.kit.edu/IntLiIon.php