Methods for Low-Temperature and Cold-Resistant Design of 18650 Battery
Blog | Published by Alex on December 19, 2025
The 18650 lithium-ion battery is widely used in power tools, energy storage systems, electric vehicles, and outdoor equipment due to its high energy density, standardized dimensions, and mature manufacturing processes. However, in cold climates or winter outdoor applications, low temperatures significantly degrade its discharge performance, capacity retention, and even pose safety risks. Therefore, enhancing the low-temperature tolerance of
18650 battery has become a critical focus in battery technology optimization. This article explores key approaches to cold-resistant design from material, structural, and system-level perspectives.
First, the low-temperature adaptability of the electrolyte is central to battery performance in cold environments. Conventional carbonate-based electrolytes suffer from increased viscosity, sharply reduced ionic conductivity, and even partial solidification below –20°C, severely hindering lithium-ion transport. To address this, researchers incorporate low-freezing-point solvents—such as methyl formate or gamma-butyrolactone—or add co-solvents like fluoroethylene carbonate (FEC) to lower the freezing point and improve ionic conduction at subzero temperatures. Additionally, optimizing lithium salts—for example, partially replacing LiPF₆ with LiFSI—enhances both stability and conductivity in cold conditions.
Second, electrode material modification plays a vital role in improving low-temperature performance. On the cathode side, high-nickel NMC materials offer high energy density but exhibit severe polarization at low temperatures, while lithium iron phosphate (LFP) suffers from intrinsically poor electronic and ionic conductivity. Strategies such as nanostructuring, carbon coating, or metal doping can significantly enhance electron transport. For the anode, graphite exhibits sluggish lithium intercalation kinetics at low temperatures, increasing the risk of lithium plating and potential safety hazards. Alternatives like hard carbon, lithium titanate (LTO), or silicon-carbon composites mitigate these issues. Although LTO sacrifices some energy density, it delivers excellent low-temperature cycling stability and safety.
Third, cell structure and thermal management design are equally important. Internally, optimizing tab placement and minimizing internal resistance in the 18650 battery reduces heat loss during low-temperature discharge. At the pack level, integrating self-heating mechanisms—such as embedded heating films or pulse-based self-heating technologies—can rapidly raise the cell temperature to an optimal operating range before use. Furthermore, thermal insulation strategies (e.g., aerogel layers) help retain heat and extend usable runtime in frigid environments.
Finally, precision in manufacturing processes directly impacts low-temperature performance. Strict moisture control prevents exacerbated side reactions in the cold, while uniform electrode coating and optimized calendering density ensure consistent lithium-ion pathways even under low-temperature stress.
In summary, designing cold-resistant 18650 battery requires a holistic approach that integrates advanced electrolytes, engineered electrode materials, structural refinements, and intelligent thermal management. With ongoing advances in materials science and smart temperature-control technologies, future 18650 battery are poised to operate efficiently and safely at temperatures as low as –40°C, enabling reliable power solutions for polar expeditions, aerospace applications, and renewable energy systems in extreme cold regions.
