Carbon fiber composites with 2D microvascular networks for battery cooling

- A battery packaging scheme is presented using carbon/epoxy composites.
- Composites with 2D microvascular networks were fabricated using sacrificial PLA.
- Different network designs were compared using thermal tests with an IR camera.
- CFD simulations were performed in Fluent and agreed well with experiment.
- Gradient-based optimization was used to improve cooling performance.

Electric vehicle (EV) batteries require both thermal regulation and crash protection. A novel battery packaging scheme is presented that uses microvascular composite panels with 2D channel networks to accomplish both objectives. Microvascular carbon fiber/epoxy composite panels are fabricated by vacuum assisted resin transfer molding, with the channel network formed by post-cure vaporization of an embedded polylactide channel template. Panel cooling performance is evaluated for parallel, bifurcating, serpentine, and spiral channel designs at different coolant flow rates and channel diameter. The spiral design provides the best thermal performance, but requires high pumping pressure (>100 kPa) at the flow rates needed for adequate cooling (>30 mL min−1). The bifurcating design and a network obtained by computational optimization offer much lower pressure with slightly reduced thermal performance. Channel diameter has negligible effect on cooling performance, but strongly affects pumping pressure. Computational fluid dynamics (CFD) simulations are also performed and correlate well with the experimental data. Simulations confirm that microvascular composite panels can cool typical battery cells generating 500 W m−2 heat flux below the target temperature of 40 °C.

A novel battery packaging scheme is presented using microvascular carbon fiber/epoxy composites that simultaneously cool the battery cell and protect it from external damage.87