Design and Fabrication of Multifunctional Structure-Power Composites for Marine Applications

Abstract

Various subsystems in marine applications, especially unmanned underwater vehicles, compete for space. Multifunctional structure-battery (SB) composites combine structure and power functions through the use of high-performance fiber reinforced polymer layers and lithium ion cell batteries, to create volumetric opportunities for increase in overall power generation capacity and/or payload. This paper focuses on the design and fabrication aspects of the SB composites. The design objectives are to achieve or exceed structural performance of traditional marine composites while attaining a volumetric energy density of 50 Wh/L with similar buoyancy levels and dimensional sizes. The design process reveals that all four objectives can be achieved only if the components related to energy storage have the same mechanical and physical properties as the material being replaced. With commercially available batteries, at least three out of four objectives are met for the proposed SB designs. Selection of materials and fabrication methods are heavily influenced by the temperature limit of the battery cells, cell surface preparation for adhesion and load transfer, and power bussing layout. A companion paper addresses multifunctional performance characterization of these composites.