Computational modelling of structural battery composites
Doktorsavhandling, 2022

Batteries and surrounding structures (e.g. battery modules and packs) in electrical vehicles and devices are often designed in a way that prevents the electro-chemically active part of the battery cells from being exposed to mechanical loads during operation/service. This means that the energy storage capability is added as a monofunctional addition to the system (i.e. it only provides one functionality, storing energy). Hence, one of the main drawbacks of the existing technology is its energy storage to weight ratio, in terms of the complete system. A viable route to improve this ratio is to develop energy storage solutions with the ability to sustain mechanical loads. Indeed, by adding this additional functionality, such solutions offer significant system mass and volume savings and allow for innovative future design of electric vehicles and devices.

The structural battery composite material is made from carbon fibre reinforced structural battery electrolyte (SBE), and exploits the multifunctional capability of the material constituents to facilitate electrical energy storage in structural components. Due to its inherent multifunctionality, the physical phenomena occurring within the material during operation will interact. Further, due to the fact that the studied material is intended to perform multiple functions some of the couplings between the physical processes are expected to be more pronounced, and critical to design, as compared to conventional batteries. Hence, to accurately predict and evaluate the combined performance of structural batteries, coupled multiphysics models are needed.

In this thesis, a computational modelling framework to predict the coupled thermo-electro-chemo-mechanical performance of structural batteries is developed. The framework is utilized to study the essential couplings between the physical processes and numerical predictions are compared favourably with experimental data. It is shown that two-way coupling between the electro-chemical and mechanical processes is important to account for when evaluating the combined electro-chemo-mechanical performance of structural batteries. Further, it is shown that the convective contribution to the mass flux of ions in the SBE, as well as the thermal effects during operations are crucial to consider when evaluating the combined performance. Moreover, the framework is extended to study an electro-chemically driven actuator and sensor utilizing carbon fibre-SBE electrodes. Finally, in addition to the modelling work a laminated structural battery with unprecedented multifunctional (i.e. combined mechanical and electro-chemical) performance is manufactured and characterized, featuring an energy density of 24 Wh/kg and an elastic modulus of 25 GPa and tensile strength exceeding 300 MPa.

Thermo-electro-chemo-mechanical coupling

Carbon fibre composites

Li-ion batteries

Multifunctional materials

Finite Element Analysis (FEA)

VDL, Chalmers Tvärgata 4C
Opponent: Prof. Angelo Simone, Department of Industrial Engineering, University of Padova, Italy


David Carlstedt

Chalmers, Industri- och materialvetenskap, Material- och beräkningsmekanik

A structural battery and its multifunctional performance

Advanced Energy & Sustainability Research,; Vol. 2(2021)

Artikel i vetenskaplig tidskrift

Electro-chemo-mechanically coupled computational modelling of structural batteries

Multifunctional Materials,; Vol. 3(2020)

Artikel i vetenskaplig tidskrift

Computational modelling of structural batteries accounting for stress-assisted convection in the electrolyte

International Journal of Solids and Structures,; Vol. 238(2022)

Artikel i vetenskaplig tidskrift

Experimental and computational characterization of carbon fibre based structural battery electrode laminae

Composites Science and Technology,; Vol. 220(2022)

Artikel i vetenskaplig tidskrift

D. Carlstedt, K. Runesson, F. Larsson and L.E. Asp, On the coupled thermo-electro-chemo-mechanical performance of structural batteries with emphasis on the thermal effects

D. Carlstedt, K. Runesson, F. Larsson, R. Jänicke and L.E. Asp, Hierarchical modeling of a structural sensor-actuator comprising beam action and electro-chemical-mechanical interactions

The structural battery composite is a material with the ability to store energy, i.e. work as a battery, while simultaneously function as a construction material in a structural system. Hence, by combining the functionality of a lightweight construction material with the functionality of a battery, highly efficient and innovative future designs of electric vehicles and devices can be envisioned. In this thesis, a mathematical modelling framework for evaluating the combined thermo-electro-chemo-mechanical performance of structural battery composites is developed. The developed framework is used to study some of the complex interactions between the different physical phenomena occurring during operation/service. In addition, we show that the same framework can be used to predict the behaviour of a similar material which, instead of the battery functionality, can change shape and sense when load is applied to the structure. Moreover, experimental studies are performed to evaluate the precision of the developed modelling framework. Finally, a structural battery design with extraordinary, combined battery and construction material functionality is demonstrated. In summary, the developed mathematical framework in this thesis provides a tool for studying and predicting the coupled behaviour of this novel type of material, and can be used to guide the design of next generation structural battery composites.

Structural pOweR CompositEs foR futurE civil aiRcraft (SORCERER)

Europeiska kommissionen (EU) (EC/H2020/738085), 2017-02-01 -- 2020-02-28.

Beräkningsbaserad modellering av elektrokemisk aktuation av en klass av kolfiber-kompositer

Vetenskapsrådet (VR) (2020-05057), 2021-01-01 -- 2024-12-31.

Strukturella batterikompositer för viktlös energilagring

Rymdstyrelsen (2020-00256), 2021-01-01 -- 2023-12-31.

Realising Structural Battery Composites

European Office of Aerospace Research and Development (EOARD) (FA8655-21-1-7038), 2021-08-01 -- 2024-07-31.

Skadetålighet hos strukturella batterier

Amerikanska flygvapnets kontor för strategisk forskning (AFOSR) (FA9550-17-1-0338), 2017-09-30 -- 2020-09-29.


Hållbar utveckling

Innovation och entreprenörskap






Teknisk mekanik


Kompositmaterial och -teknik


C3SE (Chalmers Centre for Computational Science and Engineering)

Chalmers materialanalyslaboratorium



Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5096



VDL, Chalmers Tvärgata 4C

Opponent: Prof. Angelo Simone, Department of Industrial Engineering, University of Padova, Italy

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