Design of a novel cooling system for high performance battery packs

MTC's Solution

MTC performed a requirement capture for the intended system, then conducted in-depth research into academic papers and past projects, relating to innovative thermal management systems and materials within several industries, and thermal modelling of state-of-the-art automotive thermal management systems.  Our observations recognised that the full surface area of battery cells was not effectively utilised in cooling the cells, a performance limiting characteristic which could be exploited in the creation a new system. The information gathered from this research was used to develop a concept design which was validated using thermal simulation, before being iterated several times to develop an improved design with better performance.

This approach enabled the creation of a design that was manufacturable with several different materials and advanced manufacturing methods. Which when combined, could dramatically improve the thermal performance of a battery pack under high current applications when compared to the industry standard systems. 

The developed concept utilised fluid cooled channels which slotted between the battery cells. These channels then drained into a manifold which ran the coolant under the cells to provide bottom cooling, whilst also providing a way to collect the coolant into a single exit point for recirculation. The use of the vertical side cooling channels allowed for the coolant to be provided to each channel separately via a top manifold, creating a parallel cooling system. Utilising a parallel cooling system meant the coolant provided to each cell was at a similar temperature unlike series cooling systems (one coolant channel is run past numerous cells), in which the coolant heats up as it runs through the system leading to a larger variance in coolant and therefore cell temperature. The cooling channel geometry was designed to allow up to 10% cell growth during use and the system contained fire retardant foam between the cells to absorb this growth whilst also preventing thermal run-away.

The system and its geometries were designed for additive manufacturing, which provided a large array of opportunities to improve performance. The improved design freedom associated with this manufacturing method allowed for the combining of numerous components to reduce assembly processes, whilst allowing for the incorporation of complex geometries to improve contact area with the cell and open up potential future mass reduction by replacing solid internal bodies with lattice structures. Additive manufacturing also allowed for the use of novel material to further improve the mass and thermal properties of the parts.

Throughout the design process, MTC’s modelling and simulation team performed thermal analysis on a coupon-scale model to inform the design concept The model was then developed into a full system, providing The MTC with thermal data to compare with that found in academic studies of state-of-the-art electric vehicle battery thermal management systems.

The Opportunity

This programme showcased the value of modelling and simulation tools in developing innovative solutions in thermal management. Whilst the conceptual solution has potential impact for batteries in improving their performance and lifespan, the engineering design has significant value across a range of engineering challenges.