Electro-Thermal Degradation Modeling for Fast-Charging Large-Format Prismatic Cells
Electro-thermal degradation modeling reveals that internal thermal gradients accelerate localized lithium plating and active inventory loss during fast charging.
Large-Format Prismatic Cells
Meaning
High-capacity electrochemical energy storage units housed in rigid rectangular metal or plastic casings. These large-format prismatic cells offer higher energy density and better space utilization within a pack compared to cylindrical alternatives. They are the preferred form factor for utility-scale energy storage and long-range electric vehicles due to their ability to provide high amp-hour ratings in a single enclosure.
Physical Construction
Construction of the internal assembly involves wound or stacked electrode sheets that maximize the active material volume. Because large-format prismatic cells use a hard shell, they provide structural support and simplify the cooling plate integration in modular battery designs.
Thermal Performance
Performance of the thermal management system is more complex due to the distance heat must travel from the center of the jelly roll to the outer casing. While large-format prismatic cells reduce the number of electrical connections needed in a pack, they require precise compression systems to prevent the flat sides from bulging during the expansion of the anode. This swelling is a natural result of the lithiation process but must be controlled to maintain the contact between the electrode layers and the current collectors.
Design engineers use heavy end-plates and tension straps to apply the necessary force across the face of each cell.
Manufacturing Scale
Scale of production for these units has increased as global gigafactories standardize around specific dimensions like the VDA or high-capacity LFP formats. Using large-format prismatic cells lowers the cost per kilowatt-hour by reducing the overhead associated with cell-to-pack assembly and monitoring electronics.