THT in partnership with Imperial College London and Cranfield University have been awarded funding from Innovate UK under the Government’s Industrial Strategy Challenge Fund: The Faraday Challenge.
The selected project is part of the Innovation R&D, round 3 category. THT have already been working with Imperial College on a feasibility Faraday project to develop an Isothermal Control Platform (ICP). The platform offers precise regulation of battery temperatures using multiple zone control. In addition to the physical control of the cell surface temperature, the cell internal temperature is predicted via a three dimensional heat transfer model. This leads to a system which is highly thermally stable thereby improving the accuracy and quality of data obtained during charge, discharge and cycling.
Traditional chambers based on air convection are the industry standard thermal control method used in cell characterisation. However, thermal control through air convection alone is not sufficient during vigorous cell cycling. In an environmental chamber, the cell temperature will rise significantly during cell charge/discharge and drive cycle testing. This is a particular problem for high C rate testing. Changes in cell temperature have a significant effect on cell performance. Not only will this lead to poor data being gathered, but some test regimes will not be possible as the temperature would become dangerously high and lead to thermal runaway.
Holding the battery constant temperature in the ICP provides much more usable data for cell modelling and characterisation that will ultimately translate into significant gains in battery performance, reliability and safety.
The latest funding will enable THT to take the platform from its current prototype configuration to a pre-commercial system over an 18 month period starting in July. The Imperial team will focus on developing test protocols, and are joined by researchers from Cranfield who will enhance the team's capabilities and give additional momentum to establishing these tests as internationally recognised standards.
Figure below: Cell surface temperature and voltage characteristic of a 5Ah Kokam NMC cell during a 5C (25A) constant current discharge.
Discharge tests were performed in a standard environmental chamber, in a THT ARC (near-adiabatic conditions) and the ICP.