SAMPE Journal - March/April 2022 - 64

MEMBER NEWS / MARKET & TECHNOLOGY OVERVIEW
Advances and Challenges in Structural
Battery Composites
Leif E. Asp and Johanna Xu
Dept. Industrial and Materials Science, Chalmers University of Technology, 412 96 Gothenburg, Sweden
A schematic illustration of the structural battery and its application across transport modes (illustration by Yen Strandqvist,
Chalmers university of technology).
S
tructural battery composites belong to a group of materials that can store electrical energy while carry mechanical
loads. The structural battery composite laminate contains carbon fibres that serve simultaneously as
an electrode, electron conductor, and reinforcement. The fibres are contained in a structural electrolyte matrix for
mechanical load transfer and transport of Lithium ions between the electrodes. Recent research breakthroughs
pave the way for essentially 'massless' energy storage in electric vehicles and other equipment. Massive mass reductions
can be achieved as structural battery composite laminates replace parts of the construction materials in,
e.g., the body-in-white of a car or the interior of an aircraft and the conventional Li-ion battery.
Electric vehicles are essential for decarbonizing transport. The European Union, UK, and Norway in Europe as
well as California and Canada plan to phase out the sale of fossil-fuelled vehicles by 2030 at the latest. In a recent
comment in Nature, Shaffer, Auffhammer and Samaras point out the issue of ever heavier vehicles and the need
to reduce vehicle mass for realisation of energy efficient transport solutions.1
Shaffer and co-workers also identify
that lighter vehicles will increase drive range - which is important for the widespread adoption of electric vehicles.
Lightweight solutions are even more imperative for electric aircraft. Shaffer et al. further recognize efforts to make
the car frame itself the medium to store electrical energy but conclude that research and development is needed
to improve conductivity, strength and how structural batteries handle crashes. Here, we give our view on opportunities
and challenges in structural battery composites and their utilization in electric vehicles across transport
modes.
Current state-of-the-art structural battery composites have moderate energy storage density and elastic modulus.
A structural battery composite with an energy density of 24 Wh/kg at an elastic modulus of 25 MPa was
recently demonstrated.2
These properties are well shy of those of the monofunctional structures and batteries they
are to replace. Nevertheless, the potential benefits offered by carbon fibre based structural battery composites are
enormous. In a recent study Carlstedt and Asp analysed the effects on systems mass and drive range of electric cars
replacing parts of their exterior, interiors, space frame and traction battery with structural batteries.3
drive range from the introduction of structural batteries into existing electric vehicles is substantial. Comparative
The effect on
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