AEC-Q200 qualified fuses play a critical role in the automotive environment
■ The surface-mount 885 Nano2® series has a voltage rating of up to 500 V DC , with an available interrupt rating of 1,500 A at 350 V DC . These compact fuses can be used in Li-ion battery packs, the BMS and HV DC/DC converters. ■ The surface-mount thin film chip fuse series 437A features voltage ratings from 32 V DC to 125 V DC and an interrupt rating of 50 A at the rated voltage. With their small footprint and fast response time, these are
ideally suited for secondary circuit protection of compact automotive electronics such as the LED headlights, the navigations system, the TFT display, etc. ■ The through-hole ceramic body PICOII® 521 series is a very fast acting fuse in a space saving sub-miniature package. The voltage rating is 75 V, with an interrupt current rating of 300 A at the rated voltage. These can be used for BMS protection.
Conclusion
EVs require more electronic and electrical power conversion components and modules. Fuses play a critical safety role, not just for the electronic components, wiring, and devices they protect, but also for the personnel operating the vehicle. The inclusion of fuses
in the AEC-Q200 qualification standards ensures that these
vital components meet a uniform standard. Littelfuse has a range of AEC-Q200-qualified fuses that can be used in a variety of EV overcurrent protection applications.
Figure 1: A representation of the AEC-Q200 Rev E stress tests specified for fuses. (Image source: Littelfuse)
The Rev E update to AEC-Q200, released in March 2023, adds the reliability requirements for fuses. As shown in Figure 1, Rev E includes a comprehensive list of stress tests that encompass both the environmental and physical stress factors mentioned above. As shown in Figure 1, the AEC-Q200 Rev E stress conditions are stricter than typical non- automotive tests. Some key tests are now added, such as the operational 1,000 hours life test at the maximum specified operating temperature. The test methodology for fuses requires
pre-stress and post-stress resistance measurements, along with current carrying capacity and overload tests done post-stress. The goal of AEC-Q200 Rev E is to provide a common standard that manufacturers can use to design and test fuses used in the automotive market. Littelfuse AEC-Q200 Rev E qualified fuses Littelfuse has a long history in automotive fuse development and production. They first introduced automotive fuses in the 1930s,
and their ATO® fast-acting blade fuses are considered the global standard. Littelfuse contributed to the development of the Rev E qualification stress tests for fuses, as their internal qualification tests for automotive fuses were already aligned with AEC-Q200 Rev E. Below is a list of details on some of their AEC-Q200 qualified fuses: ■ The cartridge 828 series features a high voltage rating of 1,000 V DC , with an interrupt rating of 10 kA at the rated voltage. They are targeted for OBC and PDU.
Figure 1: A representation of the AEC-Q200 Rev E stress tests specified for fuses. (Image source: Littelfuse)
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