Jelly roll (battery)
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- positive terminal
- outer metal casing (also negative terminal)
- positive electrode
- negative electrode with current collector (metal grid, connected to metal casing)
- separator (between electrodes)
The jelly roll or Swiss roll design is the design used in the majority of cylindrical rechargeable batteries, including nickel–cadmium (Ni-Cd), nickel-metal hydride (Ni-MH), and lithium-ion (Li-ion). The design has this name because the cross section of the battery looks like a Swiss roll.
In this design, an insulating sheet is laid down, then a thin layer of an anode material is laid down, a separator layer is applied, and a cathode material is layered on top. This sandwich is then rolled up and inserted into a hollow cylinder casing. The battery is sealed, metal contacts are attached, and an optional button top is applied if the battery is intended to replace an AAA/AA/C/D alkaline battery. A label with the brand name is then applied, or a blank protective label, often green (for Ni-MH) or blue (for Ni-Cd) for a generic or OEM battery.
Occasionally, the design is also used for primary (non-rechargeable) batteries, although most primary batteries use the conventional rod-paste-tube design.
The Swiss roll design is likewise used for the plates of cylindrical capacitors.[1][2]
References
- ^ Tatum, Jeremy. "5.20: Real Capacitors - Physics LibreTexts". Retrieved 8 June 2023.
- ^ "Supercapacitors: Electrical Characteristics, Modeling, Applications, and Future Trends". IEEE Access. doi:10.1109/ACCESS.2019.2908558. hdl:2454/34938. Retrieved 8 June 2023.
Most commercial supercapacitor cells are cylindrical[...]. This shape is achieved by rolling up a jelly roll consisting of two aluminum foil current collectors with the electrode active material deposited on both sides.