VDE operates a testing site in Offenbach, where Li-Ion battery packs of up to 400kg (850lbs) can be tested.
Safety of EVs might be improved if pointier procedures for check and registration were employed, opines VDE. Examination of fire hazards of batteries in EVs weren't up to the job.
Modern Li-ion battery packs must be operated in a certain temperature range. If cooling fails, e.g. after an accident, overheating may occur, or even fire in the worst case. According to VDE, the established rules don't cover these cases, with really critical differences between real-world accidents and the test procedures. Usually only pressure tests were conducted. In real accidents, impact-like loads with high impulse are dominant.
One main request of VDE is to look at failure of singled out electronic parts in test procedures. The battery should switch to a safe state, e.g. by terminating a charging process in an instant. The battery management software should be examined for possible errors, too. The current rules wouldn't stress that enough.
They find the standards lacking for the high voltage on board circuitry. Some drive trains in an EV operate at voltages in excess of 800V. After an accident there must be paramount assertion that these components are free of voltage, and that no discharge currents travel across body panel parts, even after strong deformation. The existing rules from UN EE-R100 define minimum standards here, but would fail to take real-world circumstances into full consideration, e.g. wet or dirty vehicle.s
