Zero Weight Batteries–Electrolyte Optimization

In modern Electrical Vehicles (EV), the electric battery consists of around 1/4th of total car weight and consumes significant space [1]. These issues lead researchers to explore options for so called zero weight or structural batteries (SB) which not only provide the power, but also contribute to the structural strength of a product. Due to superior multifunctional (electrochemical and mechanical) properties, carbon fiber reinforced polymer (CFRP) composites are ideal for the structural battery purpose [2-4]. CFRP composites consist of carbon fibre (CF) reinforcement and a binder resin which is generally epoxy due to its superior mechanical properties. An electrolyte in a battery provides the medium for the transportation of ions from one terminal to other during charging and discharging cycles. One major issue with SB is the choice of electrolyte with multifunctional properties. However, epoxies are insulator and does not help transport the ions, on the other hand ionic liquids (IL) which exhibit good ionic conductivity, lack the mechanical performance. One solution is to use a phase separated solid polymer electrolyte (SPE) using one constituent with good ionic conductivity and other with good mechanical properties.
The main challenge with using phase separated SPE is that the ratio of the constituents inversely affects the multifunctionality of SPE. For example, increase in IL’s ratio worsen the mechanical performance and vice versa. Some researchers addressed this issue in recent years for optimizing ratios of constituents and their effect on electrochemical and mechanical performance of SBs [5-7].
Curing history of epoxy resin and it’s viscosity is vital in deciding the mechanical properties of the CFRP composites and the effect of adding an IL in the epoxy on its curing properties is still unknown. Also, the variations in the viscosity of the epoxy in such mixture is not known yet. Current project addresses these issues.
The aim of this project is to study the effect of adding the IL in epoxy on variations in the viscosity of the epoxy as well as its impact on curing of the epoxy in a systematic way. Variation in viscosity of the resin is important to understand because it is vital for the impregnation and wetting of reinforcement fibres which has crucial effect on the properties of CFRP. This study would greatly impact on optimizing the multifunctional properties of SPE in SBs.
One method to develop phase separated SPE is to self-assemble the block copolymers using a self-assembly process [22, 23]. with this method highly ordered and organized bi-continuous phases can be obtained [24]. However, more practical approach is to use the phase separation during the polymerization [25], because it does not require the bespoke synthesis of structure forming agent. This method will be used in proposed project, because of its applicability to industry.
SBs are future of EVs, electric UAVs, robots as well as wind turbines. The tower of the wind turbine blade can be made of SBs, so that the electricity can be directly stored and distributed. One of our partners is epoxy manufacturing industry who are supplier of resins to wind turbine OEMs as well as to the automobile sector. Another partner is the composite manufacturer/supplier of automobile and aerospace sector. Both of our partners have great interest in this project. Their letters of intent are included in the application.

Please find the attached document.