Engineering materials that can store electrical energy in structural load paths can revolutionize lightweight design across transport modes. Stiff and strong batteries that use solid‐state electrolytes and resilient electrodes and separators are generally lacking. Herein, a structural battery composite with unprecedented multifunctional performance is demonstrated, featuring an energy density of 24 Wh kg−1 and an elastic modulus of 25 GPa and tensile strength exceeding 300 MPa. The structural battery is made from multifunctional constituents, where reinforcing carbon fibers (CFs) act as electrode and current collector. A structural electrolyte is used for load transfer and ion transport and a glass fiber fabric separates the CF electrode from an aluminum foil‐supported lithium–iron–phosphate positive electrode. Equipped with these materials, lighter electrical cars, aircraft, and consumer goods can be pursued.

This paper addresses a new type of multifunctional lightweight composite material desired for its potential to reduce vehicle weight and ease future electrification across transport modes. We refer to these materials as structural battery composites. The paper reviews the current status of structural battery composites. Focus is on the activities performed during the last decade by an interdisciplinary team of researchers in Sweden set to realise structural battery composites from carbon fibre reinforced polymers (CFRP). The need to develop greener, safer and more competitive road and air transport has been recognised as of critical societal and commercial importance. In Europe, the ERTRAC and EPoSS strategy paper 6 and Flight-path2050 7 have been used by the European Commission to define the Green car initiative and Green vehicle as well as the Clean Sky Joint Undertaking in European Union FP7 and H2020 research funding frameworks. For road transport electrification of urban mobility and transport has been highlighted as a most urgent research area. In addition, the Green vehicle initiative identify the need for advanced lightweight materials to realise future lightweight electric vehicle solutions. To this, Airbus has expressed a vision for an all-electric regional aircraft for 100 passengers by year 2050! The research on structural battery composites is conducted in this setting with ambition to pave the road for 'mass-less' energy storage in future vehicle structures. This will be achieved by realisation of multifunctional lightweight composite materials that simultaneously can carry mechanical loads and store electrical energy. Such materials will allow radical weight savings for future electric and hybrid vehicles,

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Structural batteries are multifunctional composites that combine load-bearing capacity with electro-chemical energy storage capability. The laminated architecture is considered in this paper, whereby restriction is made to a so called half-cell in order to focus on the main characteristics and provide a computational tool for future parameter studies. A thermodynamically consistent modelling approach is exploited for the relevant electro-chemo-mechanical system. We consider effects of lithium insertion in the carbon fibres, leading to insertion strains, while assuming transverse isotropy. Further, stress-assisted ionic transport is accounted for in addition to standard diffusion and migration. The relevant space-variational problems that result from time discretisation are established and evaluated in some detail. The proposed model framework is applied to a generic/idealized material representation to demonstrate its functionality and the importance of accounting for the electro-chemo-mechanical coupling effects. As a proof of concept, the numerical studies reveal that it is vital to account for two-way coupling in order to predict the multifunctional (i.e. combined electro-chemo-mechanical) performance of structural batteries.