Title: Nanofluid In Battery Cooling System with Wavy Channel CFD Simulation, ANSYS Fluent Training

For thermal control in modular lithium-ion batteries, nanofluid cooling systems with wavy or stair-shaped channels offer an incredibly effective option. These systems disperse heat more efficiently than traditional coolants by using the better thermal conductivity and heat transfer capabilities of nanofluids, which are fluids packed with nanoparticles. The coolant flow is more turbulent due to the wavy or stair-like channel shapes, which raises the heat transfer coefficient and encourages a more even temperature distribution across the battery modules. This time, based on the reference paper entitled “ A novel nanofluid cooling system for modular lithium-ion battery thermal management based on wavy/stair channels [1]” published in International Journal of Thermal Sciences, a CFD simulation is executed.

• Reference [1]: Sarchami, Amirhosein, et al. “A novel nanofluid cooling system for modular lithium-ion battery thermal management based on wavy/stair channels.” International Journal of Thermal Sciences182 (2022): 107823.

Figure 1- Schematic of BTMS system [1]

Simulation Process

The three primary solid components of this system—the stair channel, the wavy channel, and the copper sheath—each carry out a distinct function and are utilized to cool 18650-type batteries. With a nominal capacity of 2.75 Ah, these batteries have dimensions of 65 mm for height and 18 mm for diameter. Keep in mind that a real battery pack for an electric automobile can have a large number of batteries. For instance, the Tesla Model S is made up of 7104 18650-type batteries, which are divided into 16 sheets. The Al2O3 nanofluid mixed with water liquid is flowing through the wavy channel. This mixture is modeled considering a single-phase approach.  The heat produced by battery cells is applied as a heat flux on the walls.

Post-processing

The wavy channel cooling system has a clear gradient pattern in the way temperatures are spread out, and the temps stay around 298K all the time. The channels’ wavy shape makes areas with high and low fluid contact that change over time. This is clear from the different color intensities in the contours. The wavy shape seems to improve mixing and heat transfer by creating secondary flows and swirls at the curved parts, which can be seen most clearly in the way the temperatures change along the channel walls.

Observing views from different angles make it clear that the cooling system does a good job of controlling temperature. The temperature difference slowly grows from the entry to the outlet areas. The blue areas, which mean cooler temperatures, are mostly at the entrance, and the warmer tones (green to orange) move toward the exit. This pattern shows that the wavy channel design effectively helps heat escape while keeping the system’s temperature rise under control, which is very important for proper battery thermal management. The even temperature distribution across the channel cross-sections shows that the nanofluid mixes well, which is probably helped by the wavy shape, which creates turbulence.

Figure 2: Temperature distribution around the battery system with wavy channel