As the world aims to reduce its carbon emissions and reliance on fossil-fuel, electrification has become a key aspect that is taking increasing prominence in many industries. At the center of it all is the battery, and the world needs a lot of them. However, with their high price still an issue and to continue becoming greener, there is a need to produce high-quality and cost-effective batteries.
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In the battery industry, one of the main aims is to keep production costs down. Currently, one of the most expensive parts of a battery’s production phase is the coating process as it consumes high amounts of energy and takes a lot of time. Additionally, this is the stage where a lot of emissions are created. Therefore, as the industry tries to be more efficient in terms of pollution, energy and time needed to create batteries, one of the methods to accomplish this is by modifying the drying process.
The Coating Process
Traditionally, the drying process is carried out by applying the active material, which is semi liquid, on the current collector. Following this, it needs to be dried in an oven, which is very time consuming and adds expense in terms of energy for battery production. This stage typically takes 12-24 hours but can be more for certain electrodes. Furthermore, the electrodes need a substantial amount of time to completely dry as if they have any residual moisture or solvent, they will not function properly nor will they meet their expected longevity prior to their expected deterioration in performance. Consequently, any effort to reduce these factors will result in the ability to create more batteries with greater efficiency and a lower price point.
An alternative would be to use dry coating instead, where the active material on the current collector would already be dry, removing or minimizing the need for a drying process. However, as this is a complicated process which requires new capex, and is not yet used commercially, the industry is still working to find the right material combination. As a result, a change is needed to make the drying process more effective.
The Coating Process with 3D Electrodes
While traditional 2D electrodes have a smooth surface, 3D electrodes have a porous structure, which enables the active material to be embedded and distributed more homogeneously. When it comes to the dry coating process, the robustness and surface area of the electrode can improve adhesion of the active material with the current collector. However, this can be problematic in batteries with thick electrodes for high energy applications. As such, the traditional coating mixture has presented big issues for established companies such as Tesla, when the mixture they used unexpectedly dented the calender rollers. Indeed, to use the dry coating mixture, it must be even across the large areas of the electrodes. When this is not the case, this process quickly exposes uniformity issues and complications arise surrounding large scale production. Consequently, coating mixtures for dry coating processes have suffered many setbacks and are seeing a longer time to get to market.
3D structures can help by providing more mechanical adhesion and the ability to change compositions to provide new and more adapted formulations. For instance, if the amount of the “glue” composite can be reduced, a larger amount of active material can be carried, which would lead to a higher energy density. Moreover, the designed 3D network also provides greater accessible capacity and lower resistance in the cell.
At the same time, the 3D metal framework design can be optimized to improve the thermal heat dissipation attributes in the electrode. This can be useful when the cell is operating and gets hot, by dissipating heat to colder surroundings. Furthermore, the same conductivity via the metal framework can also help in reducing drying times by providing a thermal pathway deeper inside the electrode structure. Therefore, less solvents are used and heating the electrode more efficiently vaporizes and dries off the remaining solvents.
Addionics 3D Electrodes
With Addionics’ solution, thicker electrodes are available, which otherwise would not be manufactured with conventional foils. Indeed, due to the characteristics of the metal used in Addionics’ 3D Electrodes, the dry coating process can be more effective. In addition, if drying is needed, with a greater surface area to spread the active material on, there are more contact areas with Addionics’ cells, allowing the heat to spread faster and the drying time to accelerate. Additionally, as the industry tries to improve its battery-making process, using a smarter structure such as Addionics’ can improve battery lifetime and reduce costs.
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