Design and analysis of energy storage multifunctional composite structures with embedded lithium-ion batteries

Multifunctional carbon fibre reinforced polymer (CFRP) composite structures with embedded batteries can simultaneously carry mechanical loads and store and supply electrical energy have future potential applications in electric vehicles. This paper conducts a parametric study of CFRP laminates with embedded batteries using a finite element (FE) model that has been experimentally validated. The parametric study investigated the effects of number of embedded lithium-ion (Li-ion) polymer (LiPo) batteries (up to 400 batteries), their locations (up to a grid of 20 × 20 batteries) and thicknesses (4 mm, 2 mm and 1 mm), as well as CFRP fibre stacking sequences ([0],[0/90],[0/±45/90] and [±45]) on specific stiffness and strength (density normalised) and gravimetric energy density of multifunctional CFRP laminates. A similar FE parametric study on a curved CFRP vehicle roof with embedded batteries was also conducted. Embedded batteries can provide energy density of up to about 75 Wh/kg and 20 Wh/kg when 20 × 20 batteries were embedded in CFRP laminates and CFRP roof, respectively. However, they had adverse effects on specific mechanical properties of both CFRP laminates and CFRP roof with embedded batteries. It was suggested that the thickness of the embedded batteries should be carefully picked to achieve an optimal trade-off between desired energy density and resultant specific mechanical properties.