Objective

2

The development of new energy vehicles that use the lithium-ion batteries （LIBs） as the power source has brought into the prominence of thermal safety risks arising from high-rate chargings. The accumulation of excess heat inside the batteries results in the large temperature differences and induces the thermal runaway， thereby threatening the safety of electric vehicles. Given that the optimal operating temperature range of LIBs is 293.15-313.15 K， an efficient thermal management system is critical for ensuring the battery performance and safety. Accordingly， this study proposes a profiled spiral channel liquid cooling plate， inspired by the DNA double helix and intertwined vine structures， to meet the heat dissipation demand of 99 Ah prismatic LIBs with a 3C charging current， and evaluates its performance in obtaining an optimal charging scheme that balances the thermal and hydraulic performances.

Methods

2

The

internal resistance and entropy coefficient of a 99 A·h prismatic LIB were measured， and a volumetric heat source model of the battery was constructed based on Bernardi’s heat generation theory. A three-factor four-level L₁₆（4

3

） orthogonal experiment was designed to investigate the impacts of the length ratio， spiral angle， and width ratio on the maximum temperature， average surface temperature， and system pressure drop， and the optimal parameter integration was determined using the range analysis. For a consistent channel cross-sectional area， channel number， and inlet flow rate， the spiral channel was compared with three typical structures， i.e.， parallel， corrugated， and Tesla valve channels. The laminar flow was numerically simulated using ANSYS Fluent and verified with a grid independence study. Finally， the desirability function method was adopted to evaluate the thermal-hydraulic performance of each scheme quantitatively.

Results and Discussion

2

The range analysis results show that the spiral angle most affects the maximum and average surface temperatures， whereas the width ratio and system pressure drop are positively correlated. The optimal parameter integration is determined as a length ratio of 0.75， spiral angle of 160°， and width ratio of 0.85. Also， four types of channels show the distinct heat dissipation performances： the parallel channel delivers the worst cooling effect with a maximum LIB temperature of 319.22 K； the corrugated channel achieves a slightly improved performance； the Tesla valve channel reduces the maximum temperature to 312.92 K， owing to its distinctive flow-field characteristics； and the proposed spiral channel achieves an optimal temperature control performance， limiting the maximum temperature to 312.65 K. The inner-outer multiring structure of the proposed spiral channel extends the fluid flow path， optimizes the flow distribution， and improves the heat absorption efficiency of the coolant. In terms of the pressure drop， the parallel channel has the lowest flow resistance， whereas the spiral and Tesla valve channels exhibit the higher pressure drops owing to their complex structures. Per the desirability function calculation， the spiral channel has a desirability value of 0.086， and ranks the first in the heat dissipation among four structures.

Conclusions

2

The experimental internal resistance （1.17 mΩ） and entropy coefficient （-6.0×10

-5

V/K） accurately characterize the heat generation of the 99 A·h LIB， thereby supporting the numerical simulations. The structural parameters of the spiral channel exert different degrees of influences on the thermal and hydraulic performances， and the optimized parameter integration can balance the temperature control and flow resistance. Compared with the three conventional liquid cooling channels， the proposed spiral channel exhibits superior heat dissipation， thus providing a new design guideline for structurally optimized liquid cooling plates in the thermal management systems of LIBs.