A lithium polymer battery, or more correctly, lithium-ion polymer battery (abbreviated as LiPo, LIP, Li-poly, lithium-poly, and others), is a rechargeable battery of lithium-ion technology using a polymer electrolyte instead of a liquid electrolyte. Highly conductive semisolid (gel) polymers form this electrolyte. These. Lithium polymer cells follow the history of and cells, which underwent extensive research during the 1980s, reaching a significant milestone with 's first commercial cylindrical lithium-ion cell in 1991. The voltage of a single LiPo cell depends on its chemistry and varies from about 4.2 V (fully charged) to about 2.7–3.0 V (fully discharged). The nominal voltage is 3.6 or 3.7 volts (about the middle value of the highest and lowest value) for cells based on lithium-metal-oxides. LiPo cells provide manufacturers with compelling advantages. They can easily produce batteries of almost any desired shape. For example, the space and weight requirements of and can be met. They also have a low self. Lithium polymer cells have evolved from lithium-ion and lithium-metal batteries. The primary difference is that instead of using a liquid (such as, LiPF6) held in an (such as //), the. Like other lithium-ion cells, LiPos work on the and de-intercalation of lithium ions from a positive electrode material and a negative electrode material, with the liquid electrolyte providing a conductive medium. To prevent the electrodes from touching. Unlike lithium-ion cylindrical and prismatic cells, with a rigid metal case, LiPo cells have a flexible, foil-type (polymer ) case, so they are relatively unconstrained. Moderate pressure on the stack of layers that compose the cell results in increased capacity retention,. All Li-ion cells expand at high levels of (SOC) or overcharge due to slight vaporisation of the electrolyte. This may result in and, thus, bad contact with the internal layers of the cell, which in turn diminishes the reliability and overall cycle life. This is.