UN 38.3 Shock Test Data Collection Rich Byczek, Intertek Oct 2013 http://www.psessymposium.org/ 1 1 www.intertek.com T4: Shock • Small Cells/Batteries = 150g/6ms = consumer battery specs • Large Cells/ Batteries= 50g/11ms = automotive OEM Specs • Large Cells -> Small Batteries: Cells at 50G, Battery at 150G 2 www.intertek.com Measurement Methods Shipping of Representative shipments and packaging. • OEM selected Samples • OEM selected Methods • Small, Medium, Large sample shipments 3 www.intertek.com Measurement Methods INTERTEK RECOMMENDATIONS Pallet (LTL) and Small (UPS, FEDEX, etc) Assume small parcels have the roughest handling. Measure at package, not at device (do not assume dampening) 4 www.intertek.com Measurement Methods Measurement Equipment EDR-3C by IST - 3axis internal accelerometer - Use 2 to test both package and battery. - Set minimum G threshold, to collect primarily shock pulse data (i.e. 3G, 5G) 5 www.intertek.com Measurement Methods May require multiple runs per shipment size and type. • Set realistic thresholds to maximize data collection • Potential variation from shipment to shipment • Variation based on sample and packages size and method. 6 www.intertek.com Measurement Methods Measurement Analysis - Convert recorded data to time history Cursory review of peaks and durations Data “reduction” based on revised threshold Statistical calculation of Peak G and Duration 7 www.intertek.com Measurement Methods Resultant Shock Pulse ASSUMPTIONS • Half Sine Pulse • Small/ Large have separate parameters • Peak G level: based on max for each shipment size, regardless of method • Duration: based on average pulse width above threshold • Pulse Count: TBD, based on average pulses per shipment 8 www.intertek.com Measurement Methods NOTE on PEAK and NUMBER of PULSES: Increasing number of pulses may be a way to reduce test peak levels. Typical 1-3 pulse per direction is an ACCELERATED TEST, and therefore peak G level may not be representative of actual accumulated stress. Alternate is realistic G level, with representative test duration (number of pulses seen in a typical or multiple shipments) 9 www.intertek.com Vibration and Shock • “Test cells and batteries shall be secured to the testing machine by means of a rigid mount” • Fixturing: • Support the product • May simulate packaging • May simulate mounting in position • Not well defined currently. • Cannot assume package dampening 10 www.intertek.com Vibration and Shock • CONSIDER WHAT IS BEING SHIPPED! • CONSIDER HOW IT IS SHIPPED! • CONSIDER HOW IT IS TRANSPORTED AFTER INITIAL SHIPMENT 11 www.intertek.com THANKYOU Rich Byczek Intertek Global Technical Lead Electric Vehicle & Energy Storage 248-219-1099 [email protected] Mike Wells Vibration Test Department Manager 734-582-2900 [email protected] 12 www.intertek.com
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