New tests for electric vehicles and their components are intended to ensure the safety of passengers and systems and are a basic requirement for approval on various markets. One example is a drop test for high-voltage batteries, which is mandatory for verification for the Korean market. The following example shows how the necessary acceleration measurements inside and outside the high-voltage battery are performed during the drop test.
Drop tests must be carried out to ensure that HV battery packs do not explode or catch fire in the event of an accident. International standards differ from each other in this respect and stipulate, for example, different drop heights, battery charge levels and surfaces that the pack hits.
Region | International | USA | Korea | China | |||
---|---|---|---|---|---|---|---|
Standard | SAE J2464 | SAE J2929 | UL 2580 | USABC | FreedomCAR | KMVSS 18-3 | QC/T 743 |
Drop Height (m) | 2 | ≥ 1 | 1 | 10 | ≥ 10 | 4.9 | 1.5 |
Surface | Flat Surface | Concrete | Cylindrical Steel Object | Concrete | Wood | ||
Battery Charge Level (in %) | 95 - 100 | Maximal | 100 | 80 | 100 |
Tab 1: Comparison of international standards for a drop test of HV batteries (November 2019 - subject to correction)
In this example, a drop test is performed according to the Korean "Korea Motor Vehicle Safety Standard" (KMVSS): The specified drop height is 4.9 meters, from which the battery pack with a state of charge of 80 % shall hit a concrete surface.
Measurement task
Synchronous measurement of accelerations inside and outside a high-voltage battery during a drop test.
During the drop test, the acceleration has to be measured at various points inside and outside the battery in order to record the acting forces. The sensor data from the accelerometers inside the battery must be recorded in a high-voltage safe manner and synchronously with the values measured on the outside of the battery. In order to register even small dynamics of the acting forces during fall and impact, it must be measured with a high measurement data rate.
With this measurement technology solution, the drop test can be carried out and the forces acting in the process can be recorded precisely and synchronously. The combination of measurements of conditions inside and outside the battery pack in a single measurement chain has enormous advantages in terms of synchronization and subsequent evaluation of the data.
Thanks to the CSM safety concept and high-voltage safe measurement technology, it is also possible to use standard sensors designed for low-voltage applications.
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