DESIGN AND OPTIMIZATION OF LIGHTWEIGHT LITHIUM-ION BATTERY PROTECTOR WITH 3D AUXETIC META STRUCTURES Michael Alfred Stephenson Biharta- Ir. Sigit P. Santosa, MSME, Sc.D, IPU- Ir. Djarot Widagdo Ph.D.- Dr. Ir. Leonardo Gunawan
Bandung Institute of Technology
Jalan Ganesha 10, Bandung 40132, Indonesia
Abstract
This research study involves the design and optimization of sandwich structure based on auxetic structure to protect the battery system for electric vehicle (EV) undergoing ground impact load. In this study, a pouch battery system is used due to great potential to be the next Li-Ion battery for EV due to its simplicity, higher energy density, and higher space efficiency compared to cylindrical or prismatic battery cells. However, just like the other form of Li-Ion battery, the pouch battery cells have a high fire risk due to the battery deformation.
The sandwich structure is designed to prevent battery deformation due to ground impact. The core of the sandwich structure is filled with auxetic structure that has gone through optimization to maximize specific energy absorbed (SEA). Its performance is analyzed with non-linear finite element method. Five geometrical variables of the auxetic structures were analyzed using Analysis of Variance and optimized using Taguchis method. The optimum control variables are double-U hierarchal (DUH), the cross-sections thickness equal to 2 mm, the length of the cell equal to 10 mm, the width of the cell equal to 17 mm, and the bendings height equal to 3 mm.
The optimized geometries are then arranged into three different sandwich structure configurations. The optimized sandwich structure has optimized DUH cell as the core that has been enlarged to two times in length (single cells dimension 38x38x24 mm), arranged in 11x11x1 cells resulting in total dimension and mass of 189x189x12 mm and 0.75 Kg. The optimized sandwich structure shows that the pouch battery cells are able to be protected very well from ground impact load with the maximum deformation of 1.92 mm, which is below the deformation threshold for battery failure.
