A Review of Battery Cooling Systems for Electric Vehicles

Abstract

Battery thermal management is no longer a secondary subsystem in electric vehicles; it directly affects charging capability, usable energy, ageing, safety, and auxiliary energy consumption. This focused review compares the principal cooling approaches used for lithium-ion battery packs, including air cooling, indirect and direct liquid cooling, refrigerant cooling, phase-change materials, heat pipes, thermoelectric devices, and hybrid architectures. The literature is interpreted through a common set of engineering metrics: maximum cell temperature, temperature non-uniformity, hydraulic or auxiliary-energy penalty, packaging burden, controllability, safety, and manufacturability. Air cooling remains attractive where heat load and packaging complexity are modest, whereas liquid cold plates provide the most mature route for high-power automotive packs. Refrigerant and immersion concepts shorten the thermal path but raise sealing, dielectric, and control requirements. Passive devices such as phase-change materials and heat pipes can buffer transient peaks, yet they require a reliable heat-rejection or regeneration path for repeated duty. Recent work has increasingly shifted from single-parameter geometric studies toward multi-objective thermal-hydraulic optimization and surrogate-assisted design. The review therefore argues that future battery cooling should be assessed as a vehicle-level co-design problem rather than by peak temperature alone. Designs that retain thermal uniformity across fast charging, high ambient temperature, repeated drive cycles, and realistic pump or compressor limits are more relevant than isolated optimum points.