Polymer Lithium-ion Batteries
Polymer Lithium-ion Batteries differentiate themselves from conventional lithium-ion battery systems in the types of both electrolyte and shell used. The original design, dating back to the 1970s, when French Professor M. Armand proposed to use a dry solid polymer electrolyte. This electrolyte resembles a plastic-like film that does not conduct electricity but allows ions exchange (electrically charged atoms or groups of atoms). The polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte. In order to obtain excellent lithium ion conductivity, some gelled electrolyte has been added into Polymer Lithium-ion Batteries. Most of the commercial Polymer lithium-ion batteries used today for mobile phones are a hybrid cells and contain gelled electrolyte. In addition, instead of using a metal can as battery shell, Polymer Lithium-ion Batteries employ the Laminated Aluminum Foil as battery case, which is lighter, thinner, more flexible and safer. The advantages of Polymer Lithium-ion Batteries are listed as followings: - Very low profile - batteries resembling the profile of a credit card are feasible: cell thickness measuring as little as one millimeter (0.039 inches).
- Flexible form factor - manufacturers are not bound by standard cell formats. With high volume, any reasonable size can be produced economically.
- Lightweight - gelled electrolytes enable simplified packaging by eliminating the metal shell.
- Improved safety - more resistant to overcharge; less chance for electrolyte leakage.
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