Advanced Thermal Management for High-Tonnage EVs: Increasing Coolant Flow and Reducing Energy Losses

<div class="section abstract"><div class="htmlview paragraph">With the increasing tonnage of electric heavy commercial vehicles, there is a growing demand for higher power and torque-rated traction motors. As motor ratings increase, efficient cooling of the EV powertrain system becomes critical to maintaining optimal performance. Higher heat loads from traction motors and inverters pose significant challenges, necessitating an innovative cooling strategy to enhance system efficiency, sustainability, and reliability.</div><div class="htmlview paragraph">Battery-electric heavy commercial vehicles face substantial cooling challenges due to the high-pressure drop characteristics of conventional traction system cooling architectures. These limitations restrict coolant flow through key powertrain components and the radiator, reducing heat dissipation efficiency and constraining the operating ambient temperature range. Inefficient cooling also leads to increased energy consumption, impacting the overall sustainability of electric mobility solutions.</div><div class="htmlview paragraph">This paper presents a novel approach of optimizing coolant flow by reconfiguring the traction system layout and redesigning the coolant flow paths. These enhancements increase coolant flow by 100–200% compared to conventional systems, allowing the coolant pump to operate within its peak efficiency range. As a result, pumping power consumption is reduced by at least 33%, minimizing parasitic losses, improving vehicle range, and supporting green mobility initiatives by reducing energy waste.</div><div class="htmlview paragraph">The increased coolant flow through the radiator enhances the tube-side heat transfer coefficient, significantly improving radiator heat dissipation and allowing for higher ambient temperature operation. Additionally, the optimized cooling system enables lower fan speeds, reducing both power consumption and cooling fan noise. This verified thermal management strategy, successfully implemented in production-ready heavy-duty electric vehicles, has effectively prevented traction propulsion motor power de-rating, leading to improved vehicle performance, energy efficiency, and long-term sustainability.</div><div class="htmlview paragraph">Furthermore, a unique control strategy has been developed to dynamically regulate coolant pump and radiator fan operation by continues monitoring of each aggregate device temperatures. This optimized thermal management system ensures robust and efficient cooling.</div></div>