Batteries including Lithium Polymer Types

The use of polymers in battery construction can be categorised in three distinct ways. For example the polymer may be used in the manufacture of the battery separators used in traditional cells to provide physical separation of the positive and negative plates whilst permitting electron flow through the electrolyte. Polyester and polypropylene fibres may also be used to reinforce the battery plates themselves in traditional cells. The second function is as a battery container material which must resist chemical attack by the electrolyte and give the container mechanical strength. 

Rechargeable lithium-ion polymer cells are also available from IBT, for use in such portable applications as mobile communications and hand-held instrumentation, with a nominal voltage of 3.7 V and capacities ranging from 100 mAh to 4500 mAh at the five hour discharge rate. The polymer may be part of the electrochemical operation of the battery as in the case of lithium polymer designs. 

The performance of traditional fithium-ion cells has more than doubled over the past ten years from 280 Wh/1 (watt hour per litre) in 1995 to 580 Wh/1 in 2005 as a result of changing the chemical 

Prototypes of a 3.6 V battery can be charged with a power density of 10 kW/kg compared to the 1.0 kW/kg obtainable from a conventional lithium-ion design. NEC has already experimented with the possibility of using the ORB as a back-up power supply for desktop personal computers. 

Future trends include the adoption of a nickel-cobalt-manganese (NCM) cathode comprising a solid solution of nickel-cobalt-manganese. Further ahead, towards the end of 2006, the NCM will be replaced, by Panasonic, with the NCA, which is a blend of nickel-cobalt-aluminium dioxide. This development will increase the energy density to 620 Wh/1. 

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Nippon Kodoshi Corporation (NKK), headquartered in Kochi, Japan, has been established since 1941. NKK s product lines include separators for capacitors (aluminum electrolytic and conductive solid polymer capacitors), separators for electric doublelayer capacitors, separators for multiple types of batteries (alkaline, lithium-ion, and NiMH batteries), and lastly, inorganic and organic nanohybrid membranes. 

Studies performed by the author on various types of rechargeable batteries for EVs and HEVs reveal that lithium-based batteries are widely used by various manufacturers. The most widely used rechargeable batteries include Li-ion-manganese-dioxide, Li-ion-iron phosphate, Li-ion-sulfide, and Li-ion-polymer. Performance capabilities and other important characteristics of these batteries are described in great detail in this section, with a particular emphasis on energy density, selfdischarge rate, longevity, and power density. 

A recent solid state battery design, lithium composite cathode batteries, developed at Harwell, features a lithium ion conducting polymer electrolyte (e.g., polyethylene oxide) and a solid intercalation cathode. The battery is made up of a sandwich of lithium foil (50 pm), polymer-electrolyte (50 pm), composite cathode (various types have been studied including VsOis, TiS2, MoOj, etc., plus 5% carbon black) (56 ym) and a nickel foil current collector (10 pm). Thus total cell thickness is 150-200 pm and areas can range from cm to m. ... 

At this time the only commercially available all-solid-state cell is the lithium battery containing Lil as the electrolyte. Many types of solid lithium ion conductors including inorganic crystalline and glassy materials as well as polymer electrolytes have been proposed as separators in lithium batteries. These are described in the previous chapters. A suitable solid electrolyte for lithium batteries should have the properties... 

This chapter, in addition to surveying membrane types and production, overviews applications of gas and liquid membrane separation and polymer films as banier layers. Water purification for reuse and in desalination using reverse osmosis and nano-, ultra-, and microfiltration are discussed. Electrodialysis, dialysis, and hemodialysis are also covered. Membranes in emerging technologies are described including fuel cell membranes, membranes in lithium batteries, conducting polymer membranes, and thin film membranes used in LED and photovoltaic applications. 

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