Author: Nasim Saber (University of Iceland) - A more sustainable energy economy needs a higher share of renewable energy sources (RESs). The intermittent nature of RES necessitates suitable storage solutions as RES penetration goes up. Among available energy storage solutions, lithium-ion (Li-ion) batteries have gained significant global attention due to their high energy density, excellent capacity, superior efficiency, and long operational lifespan. The working environment has a significant influence on the behavior of Li-ion batteries. Therefore, designing an effective battery thermal management system (BTMS) is pivotal to ensure their optimal performance, safety, and longevity, particularly as they become increasingly vital in electric vehicles and stationary energy storage applications. While significant research has focused on cooling strategies to prevent overheating, heating strategies have received comparatively less attention, despite their critical role in maintaining battery performance in low-temperature environments. When Li-ion batteries operate at low temperature for a long time, their charging/discharging performances and safety will suffer from severe degradation. This review is the first review of the heating strategies to collect and analyze statistics on the growing number of studies and approaches used for heating. This review presents a comprehensive analysis of battery heating strategies, focusing on BTMS-integrated external systems (air-cooled, liquid-cooled, phase change materials, heat pipes), electric heating elements, and internal approaches (self-heating, DC (direct current), AC (alternating current), pulse heating). We evaluate the effectiveness, advantages, and challenges of each heating technique, emphasizing their impact on performance, safety, and the lifespan of Li-ion batteries. By identifying current gaps, this work aims to guide future developments in battery heating technologies that support sustainable and reliable energy systems under extreme environmental conditions.
