Introduction/ Project overview:
Crafts and industry need more skilled workers for future technologies like battery technology, electromobility, and hydrogen systems. The „TraFuSMS – Training for Future Skills for Sustainable Mobility Solutions“ project, led by the Electric Vehicle Institute of the Bochum University of Applied Sciences, the Dortmund Chamber of Crafts (Handwerkskammer Dortmund), and the Motor Vehicle Guild Bochum (KFZ-Innung Bochum), develops a modular training concept for the energy and mobility transition in the Ruhr region . Supported by Bochum Economic Development (Bochumer Wirtschaftsentwicklung) and the Chamber of Commerce and Industry Mittleres Ruhrgebiet (IHK Mittleres Ruhrgebiet), the project focuses on maintaining traction batteries, hydrogen systems, and sustainable energy solutions, combining practical learning modules with a blended learning approach.

Motivation:
With electric vehicles (EVs) on the market for several years, many of these are leaving or already left their guarantee timeframe, allowing owners to choose their desired car workshops and services without obligations from the vehicle OEM. To prepare the workers and apprentices for the upcoming tasks, such as battery estimation of said vehicles, further training and education is required. The electric vehicle institute of the Bochum University of Applied Sciences develops those trainings and thus analyses the different State-of-Health (SOH) estimation procedures relevant for implementation into the training and the subsequent workshop usage. Therefore, this work presents an overview of SOH estimation techniques of traction batteries in workshop applications.
SOH estimation methods in the workshop context:
– Short introduction to SOH (which health index is our health index?)
– Workshop procedures for SOH estimation
o Differentiation between procedure types
o Passive procedures (using only data values read from CAN)
o Active procedures (applying loads, measurement voltages, etc.)
To identify the suitability of a SOH estimation procedure for usage in a workshop application, they will be evaluated and classified. The six classification criteria will be:
– Measurement timeframe
– Measurement simplicity
– Data handling
– Method reproducibility
– Device requirements and limitations
– Safety requirements and limitations for testing
Based on these criteria, the active and passive methods will be evaluated and classified. The chosen methods for the evaluation are:
Passive methods:
– Reading SOH from EV CAN-bus
– Reading charged or capacity from EV CAN-bus and calculation of SOH in comparison to the nominal capacity
Active methods:
– DC methods
o C/3 Charge and Discharge tests for capacity measurement
o C/20 Charge and Discharge tests for capacity measurement and Open-Circuit-Voltage measurement
o Fast-charging test for comparing the aged battery to data of a new battery
o Pulsed charging methods for capacity measurement and internal resistance calculations
o DC internal resistance test
– AC methods
o AC internal resistance test
o Electrochemical Impedance Spectroscopy

Conclusion of findings and outlook:
The conclusion will summarize the findings and make a statement on how suitable the different methods are for the different workshop situations and battery level.