An Efficient Pathway to a Safe Battery in Everyone’s Garage

Authors

Dr. B. Brunnsteiner, Dr. W. Prochazka, AVL List GmbH, Graz:

Year

2022

Print Info

Production/Publication ÖVK

Summary

There are various strategies and approaches how to ensure safe battery operation or BEV usage at all. There are studies about typical time demand for passengers to escape vehicles, there are studies of typical time demands how long fire fighters or rescue teams need to be at a vehicle accident and similar investigations for finding the right target values, how long a battery must be safe after a single cell thermal runaway was detected. For legal and homologation reasons, typically 5 minutes are required. 5 minutes in which no flame or fire must come out of the battery and 5 minutes in which there is no hazardous condition allowed for the passenger after the detection and warning of a battery thermal runaway to the driver. This 5 minute target is driving current battery developments, since available and upcoming cell chemistries in combination with classical battery designs and high energy density demands are challenging the achieval of these 5 minutes. Nevertheless this target is considered too weak to ensure safe conditions for drivers or BEV owners after all. If one thinks about what happens if a battery catches fire during charging or parking in your garage – which is the case 90% of the time you own the vehicle - the 5 minutes safe escape time is not sufficient to ensure safe conditions for your garage and inhabitants in the house if connected or nearby. The news picture below show impressively what can happen in such a condition.

Hence the next generation target for all serious OEMs must be to ensure no propagation of thermal runaway in the battery at all. So, the target is to ensure for hours that a single cell thermal runaway must not lead to a fire outside the pack or to harmful conditions outside the pack.

This target which is typically called “no propagation”, is challenging current designs of components, safety design strategies and current cell designs harnessing the chemistries. The solution must be to develop new concepts and design features to ensure safe battery design considering different aspects of thermal runaway: not just thermal impacts of the tremendously high heat release, but even gas flow impacts and gas ignition risks as well as electrical risks like arcing or short circuits.
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ISBN

1920-2323-23-1

Number of pages

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