As EVs continue to make waves in the automotive industry, the spotlight is increasingly turning towards battery technology to make the next step change. A key innovation that has caught the eyes of many and that has the potential to revolutionize EVs is dry coating. One of the main steps in the battery manufacturing process, this occurs when the dry active material is coated onto the metal foil to form the electrode. From the origins of dry coating to its obstacles and benefits, dry coating can give another boost to the EV industry.
The Origins of Dry Coating
The Traditional Drying Process
Traditionally, the drying process involves mixing the electrode material with water or an organic solvent, and applying the semi-liquid active material onto the current collector, followed by a time-consuming oven drying process. This drying stage is the most energy-intensive and carbon-intensive stage of battery manufacturing. Indeed, thorough drying is essential to ensure that there is no residual moisture or solvent in the electrodes, as their functionality and expected lifespan greatly depend on it. Hence, alternative solutions to mitigate these challenges and yield a more efficient battery production at a reduced cost are needed.
Dry coating is an alternative method that eliminates the conventional drying phase. Indeed, the active material starts off dry and is applied to the current collector. Pressure and minor temperature changes are then applied to the mixture, allowing it to adhere to the foil and significantly reducing the need for a separate drying step. However, while this approach is promising, it presents complexities and has not yet seen widespread commercial implementation.
Obstacles in the Dry Coating Process
One of the main setbacks in the dry coating process is the adhesion of the dry material to the electrode. For batteries with traditional 2D foils, the dry coating material must effectively bond to the flat surface of the electrode. However, lack of texture and limited surface area can make it more difficult for the dry material to form a strong bond with the electrode surface. Due to the flat nature of the electrode, it can be challenging for the dry coating to properly stick to it when the dry coating is layered on. This can cause the battery to suffer from low mechanical stability, introducing the risk of electrode delamination, which would cause the battery to stop functioning. On the other hand, effectively dry coating comes with
Dry Coating Benefits
One of the main advantages of implementing dry coating in EV batteries lies in its ability to achieve a higher compaction density of the active materials, a crucial factor contributing to enhanced battery performance. This allows for a 20% increase in the battery's energy density when operating under identical conditions, making it a game-changing innovation in EV technology.
Due to its dry nature, dry coating doesn’t use solvents, has fewer preparation steps and needs less equipment in the overall process. As a result, capital and operational costs are reduced. Additionally, the faster process of dry coating leads to a higher manufacturing output at the same time as reducing costs. Indeed, these advantages can result in the battery’s cost being cut by at least 10%.
A More Sustainable Option
With its reduced necessity for heavy equipment, dry coating enables the simultaneous production of electrodes while decreasing the conventional factory's footprint. Moreover, this reduces the energy needed for the complete battery production. Indeed, around 39% of the energy used in the manufacturing of lithium-ion batteries is associated with overall drying processes, with the electrode drying step making up for approximately half of that consumption. Regarding dry coating, although the dry processes may still require heated rollers, the removal of drying and solvent recovery stages leads to a substantial reduction in both electricity usage and expenses.
Less Time Needed
In the case of traditional electrodes, the drying process is notably time-consuming, with some electrodes requiring as long as 24 hours to be fully dry. Dry coating offers a distinct advantage as the active material on the current collector is dryer, leading to a substantial reduction in drying time. This process significantly contributes to an overall reduction in fabrication time, making it an efficient and time-saving technique in EV battery production.
Going all the Way with Addionics
While dry coating offers numerous benefits, the technology has not yet reached its full potential for optimal utilization. With Addionics’ 3D Electrodes that use a porous metal structure, the active chemical material is embedded inside during the coating process. Consequently, the active material can be more easily inserted into the metal framework, and from both sides, allowing it to be more uniform. This results in improved mechanical stability and enhanced adhesion for 3D battery electrodes. Moreover, the dry coating technique for 3D electrodes can be integrated into the foil-based fabrication process in addition to being executed on the same production line.