Design, Modeling, and Simulation of Battery Pack Suspensions for Off-road Electric Vehicles

Open Access
Author:
Aglione, Daniel Lewis
Graduate Program:
Mechanical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
March 27, 2014
Committee Members:
  • Christopher Rahn, Thesis Advisor
Keywords:
  • Suspension
  • modeling
  • vibration
  • shock
  • battery pack
  • vehicle
Abstract:
Battery packs on commercial off-road battery electric vehicles (BEVs) are exposed to harsh environments with vibration and shock loading that can lead to battery damage and premature failure. Underground mining, for example, uses BEVs to mitigate both the ventilation costs and safety concerns associated with emissions from internal combustion engines. A BEV must have a large battery pack to allow continuous operation for an entire shift. Ensuring long life of the expensive pack often requires a suspension system to isolate damaging resonant frequencies and attenuate transient shock accelerations. In this thesis, suspensions comprising wire rope isolators and silicone safety bump stops are designed, modeled, and simulated for an example underground mining vehicle. A six degree-of-freedom dynamic model is developed that predicts battery pack responses given a variety of base acceleration inputs from the BEV. Simulation results indicate that there are many bump stop, isolator, and attachment point designs that successfully isolate battery cell resonances at 35 Hz. Two design parameters, bump stop effective thickness and maximum isolator travel, significantly affect shock attenuation. Bump stop designs can be tuned to optimize shock response without affecting vibration performance.