Influence of straight and inclined baffles on enhancement of battery thermal management system performance

Abstract

Battery thermal management systems (BTMSs) are used in electric vehicles (EVs) to regulate the heat generated by batteries while in use. Existing research on the improvement of BTMSs revealed that more research can be done by exploring different strategies to extend the service life and capabilities of EV batteries beyond the current limitations. In this study, effects of orientation of baffles; straight ( $90°$ ), inclined ( $60°$ and $30°$ ), height of baffles, thickness of baffles, positioning of baffles and number of baffles on the performance of conventional Z - Type BTMS were studied using Computational Fluid Dynamics (CFD) approach. The CFD approach was validated with existing experimental result from literature. Findings from the study showed that for straight baffle, the maximum temperature ( $T_{\max }$ ) reduces as the height of baffles decreases. Furthermore, increasing the baffle thickness from 1 mm to 2 mm, produced reduction in $T_{\max }$ by 0.26 K. For inclined baffles, by comparing the BTMS without baffles and BTMS with 2 baffles, $T_{\max }$ and maximum temperature difference ( $\Delta T_{\max }$ ) reduced by 0.82 K and 0.68 K, respectively at angle $60°$ , and reduced by 1.65 K and 1.43 K, respectively at angle $30°$ . The BTMS with 2 baffles, inclined at angle $60°$ , with height of 6 mm and thickness of 1 mm, yielded the optimum $T_{\max }$ (Lowest) value of 333.15 K, a reduction by 2.65 K when compared to the conventional Z - Type BTMS. This was also accompanied with a slight increase in $\Delta P$ by 1.12 Pa. In conclusion, it can be said that findings from this study will be beneficial in enhancing the design of BTMSs through adequate selection and utilization of baffles orientation.

Keywords: BTMS; CFD; Divergence plenum; Inclined baffles; Straight baffles.

Fig. 1

Reference Z-type BTMS geometry: a) 2D geometry with schematic; b) 3D geometry of BTMS and a 3D geometry of battery.

Fig. 2

A baffled Z-type BTMS model: a) 2D schematic view; b) 3D geometry and a baffle.

Fig. 3

Schematics of the different baffle arrangement (a) 8 Straight baffles (b) 8 Inclined baffles (c) 4 Straight baffles (d) 4 Inclined baffles (e) 2 Straight baffles (f) 2 Inclined baffles.

Fig. 4

Performance of numerical simulation with varying grid sizes.

Fig. 5

Maximum temperature comparison between Experimental Chen et al. [26] and current study simulation results.

Fig. 6

Minimum temperature comparison between Experimental Chen et al. [26] and current study simulation results.

Fig. 7

(a) 2D model, (b) Selected grid and (c) Temperature profile, of the Z – Type BTMS.

Fig. 8

Comparison of $T_{\mathit{max}}$ and $\Delta T_{\mathit{max}}$ for the cases with and without baffles.

Fig. 9

Estimated values of $\Delta P$ for the cases with and without baffles.

Fig. 10

Comparison of temperature on the batteries with and without baffles.

Fig. 11

Temperature contour profile of straight baffles.

Fig. 12

Comparison of $T_{\mathit{max}}$ and $\Delta P$ with different baffle height.

Fig. 13

Comparison of $T_{\mathit{max}}$ and $\Delta P$ with different baffle thickness.

Fig. 14

Comparison of $T_{\mathit{max}}$ and $\Delta T_{\mathit{max}}$ for the cases with and without baffles.

Fig. 15

Estimated values of $\Delta P$ for the cases with and without baffles.

Fig. 16

Inclined baffle comparison of $T_{\mathit{max}}$ on the batteries.

Fig. 17

Temperature contour profile of inclined baffles.

Fig. 18

Inclined baffle comparison of $T_{\mathit{max}}$ and $\Delta P$ for the cases with different baffle height.

Fig. 19

Inclined baffle comparison of $T_{\mathit{max}}$ and $\Delta P$ for the cases with different baffle thickness.