With vehicle range related to battery pack thermal management, the i-CoBat project – a collaboration between M&I Materials, WMG and Ricardo – aims to develop and demonstrate a new form of EV battery cooling technology based on cell immersion cooling using dielectric fluid.

This innovation promises improved power output and cell longevity, faster charging rates and lower costs, significantly addressing the key consumer issue of range anxiety, the partners claimed.

"As the automotive industry seeks to electrify its product ranges, the thermal management of high capacity batteries used for electric vehicles (EVs) is proving a significant challenge. The performance and efficiency of battery cells can deteriorate – and their ageing can be accelerated – if operating temperatures exceed the upper or lower limits of a comparatively narrow range. In extreme cases, exceeding upper operating limits can risk thermal runaway of cells, leading to catastrophic failure and potentially, fire," a statement said.

For market acceptability – and in particular, to persuade owners of liquid-fuelled vehicles to switch to an EV – charging times are a significant challenge in terms of alleviating range anxiety. Consumers seek fast recharging times, good performance and range, and competitive prices; during fast charging, however, battery cells can produce up to three times more heat energy than in normal driving and charging operations; with heating of the cells being a dominant factor in battery ageing and performance degradation. Using current battery cell technology, therefore, the requirement for thermal optimisation of pack design and operation is vitally important.

Current EV batteries packs tend to use air cooling or cold plate cooling using water/ethylene glycol or a refrigerant. The limitations of such thermal management systems act to restrict charging rates or the number of fast charge cycles that can be carried out each day. One possible answer to range anxiety could be to increase pack size, but this would significantly increase costs.  

Led by M&I Materials, the i-CoBat project is part of the government's Faraday Battery Challenge and will test an immersion cooled battery pack concept using M&I Materials biodegradable dielectric cooling fluid, Mivolt. M&I Materials have been working in advanced materials and electrical insulation for over 100 years, with a core specialism in dielectric fluids for more than 40. The innovation promises improved power output and cell longevity, faster charging rates and lower costs, significantly addressing the key consumer issue of range anxiety.

Ricardo will bring its extensive knowledge of EV battery pack and battery management system design and thermal management to the project while WMG will lend its research capabilities to address the move from research and development to commercialisation.

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