Pouch Cell
A pouch cell is a battery cell sealed in a flexible, heat-sealed laminated enclosure rather than a rigid metal can. The laminate commonly combines an aluminium barrier with polymer layers for insulation, protection, and sealing. Automotive pouch cells often use stacked electrode layers, but the defining feature is the enclosure. Pacific Northwest National Laboratory: Materials Review of Current/Near-Term Lithium Batteries
What the format changes
The pouch contributes much less mechanical restraint than a rigid cylindrical or prismatic case. The surrounding module or pack must support the broad faces, protect the edges and terminal seals, prevent bending, and apply controlled pressure while allowing normal thickness changes. Gas-producing side reactions and ageing can increase swelling, which can alter local pressure and cooling contact.
Broad cell faces offer a large potential cooling area, but effective heat removal depends on maintaining consistent contact with cooling and thermal-interface components. Argonne's BatPaC vehicle-pack model, for example, places stiff pouch cells with thermal conductors inside supported modules and uses a rack structure to maintain compression. This is one engineering implementation, not a universal pouch layout. Argonne National Laboratory: BatPaC Model Software and User's Manual
Flexible packaging can reduce cell-enclosure mass, but pack-level frames, pads, cooling parts, and protection add mass and volume. A pouch cell is therefore not automatically lighter, more energy-dense, or better than another format.
For detailed construction, cooling, support, and pack trade-offs, see Cell Formats.