Plastic lithium ion cells

One particular version of the lithium-ion gel polymer cells, also known as plastic lithium-ion cell (PLION). was developed by Bellcore (now Telcordia Technologies).In this case. Gozdz et al. developed a microporous plasticized PVdF—HFP based polymer electrolyte which served both as separator and electrolyte. In PLION cells, the anode and cathode are laminated onto either side of the gellable membrane. Good adhesion between the electrodes and the membranes is possible because all three sheets contain significant amounts of a PVdF copolymer that can be melted and bonded during the lamination step. 

Doyle, M. et al. (1996) Comparison of modeling predictions with experimental data fi-om plastic lithium ion cells. /. Electrochem. Soc., 143 (6), 1890-1903. 

Lithium secondary batteries can be classified into three types, a liquid type battery using liquid electrolytes, a gel type battery using gel electrolytes mixed with polymer and liquid, and a solid type battery using polymer electrolytes. The types of separators used in different types of secondary lithium batteries are shown in Table 1. The liquid lithium-ion cell uses microporous polyolefin separators while the gel polymer lithium-ion cells either use a PVdF separator (e.g. PLION cells) or PVdF coated microporous polyolefin separators. The PLION cells use PVdF loaded with silica and plasticizer as separator. The microporous structure is formed by removing the plasticizer and then filling with liquid electrolyte. They are also characterized as plasticized electrolyte. In solid polymer lithium-ion cells, the solid electrolyte acts as both electrolyte and separator. 

A typical lithium-ion cell consists of a positive electrode composed of a thin layer of powdered metal oxide (e.g., LiCo02) mounted on aluminum foil and a negative electrode formed from a thin layer of powdered graphite, or certain other carbons, mounted on a copper foil. The two electrodes are separated by a porous plastic film soaked typically in LiPFe dissolved in a mixture of organic solvents such as ethylene carbonate (EC), ethyl methyl carbonate (EMC), or diethyl carbonate (DEC). In the charge/ discharge process, lithium ions are inserted or extracted from the interstitial space between atomic layers within the active materials. 

PLI battery (plastic lithium ion battery) A lithium ion cell which uses a polymer electrolyte. 

Polymer electrolytes are used in lithium ion rechargeable batteries. Pure polymer electrolyte systems include polyethylene oxide (PEO), polymethylene-polyethylene oxide (MPEG), or polyphosphazenes. Chlorinated PVC blended with a terpoly-mer comprising vinylidene chloride/acrylonitrile/methyl methacrylate can make a good polymer electrolyte. Rechargeable lithium ion cells use solid polymer electrolytes. Plasticized polymer electrolytes are safer than liquid electrolytes because of a reduced amount of volatiles and flammables. The polymer membrane can condnct lithinm ions. The polymer membrane acts as both the separator and electrolyte [7],... 

The technology of rechargeable lithium batteries is being developed continuously. Goals are larger batteries, e.g. for the hybrid propulsion system of vehicles, environmentally more compatible components, especially for the cathode, lower priced materials, longer cycle lives, more inert electrodes, etc. So-called solid-state batteries with polymeric electrolyte are also to be mentioned here. They are lithium-ion cells with an inert polymer matrix or a gel, which contains the electrolytic solvent-conductive salt mix. Herewith, the use of the normal heavy steel containers, which cannot be manufactured with heavily reduced wall thickness anyway, can be abandoned and a plastic laminated aluminum foil can be applied instead. In this way lightweight and very thin cells of a card format can be made. 

For any system with a high prevalence of organic construction (plastic cases, separators) or organic solvent electrolytes (as in lithium-ion cell technologies), the rate of oxygen consumption may be directly correlated to the heat released based on a standard of 13.1 MJ kg oxygen consumed. A combination of radiant flux meters provides aU necessary data to support large-scale battery failure analysis. 

Doyle et al. [35] show how the full cell-sandwich model can be used to determine maximum and minimum salt concentrations in the ceU as a function of time, position, and current density, in order to evaluate the risk of salt precipitation and the effect of salt depletion on accessible c pacity. Experiments verified the modeks prediction that salt depletion would limit accessible capacity upon high discharge rates in BeUcore-style plastic lithium-ion batteries. Figure 6 compares model predictions to experimental discharge curves at... 

Gel polymer lithium-ion batteries replace the conventional liquid electrolytes with an advanced polymer electrolyte membrane. These cells can be packed in lightweight plastic packages as they do not have any free electrolytes and they can be fabricated in any desired shape and size. They are now increasingly becoming an alternative to liquid-electrolyte lithium-ion batteries, and several battery manufacturers. such as Sanyo. Sony, and Panasonic have started commercial production.Song et al. have recently reviewed the present state of gel-type polymer electrolyte technology for lithium-ion batteries. They focused on four plasticized systems, which have received particular attention from a practical viewpoint, i.e.. poly(ethylene oxide) (PEO). poly (acrylonitrile) (PAN). ° poly (methyl methacrylate) (PMMA). - and poly(vinylidene fluoride) (PVdF) based electrolytes. ... 

Abraham et al. were the first ones to propose saturating commercially available microporous polyolefin separators (e.g., Celgard) with a solution of lithium salt in a photopolymerizable monomer and a nonvolatile electrolyte solvent. The resulting batteries exhibited a low discharge rate capability due to the significant occlusion of the pores with the polymer binder and the low ionic conductivity of this plasticized electrolyte system. Dasgupta and Ja-cobs patented several variants of the process for the fabrication of bonded-electrode lithium-ion batteries, in which a microporous separator and electrode were coated with a liquid electrolyte solution, such as ethylene—propylenediene (EPDM) copolymer, and then bonded under elevated temperature and pressure conditions. This method required that the whole cell assembling process be carried out under scrupulously anhydrous conditions, which made it very difficult and expensive. 

Figure 2 shows a schematic diagram of a complete battery (lithium-ion battery). Several cells as the one shown in Fig. 1 are wrapped together in parallel. The schematic corresponds to a cylindrical battery. The anode, separator, and cathode materials are tightly wrapped and held together to form what is called the jelly roll (see Fig. 2(a)). The jelly roll is introduced into the container or can. The container or can should be resistant to corrosion from both inside and outside, ft should also have the required mechanical strength for the specific application [4]. The containers usually have a plastic insulator for protection of the can from the external media. 

A glance through the table of contents provides an overview of the issues commonly encountered by chemists in the automotive industry. The author discusses fuels cells, lithium ion batteries, carbon nanotubes, and nickel metal hydride technology, all of which requires the technical knowledge of a chemist but crosses the lines of various disciplines. He covers future technology including items such as battery technology, fuel cell membranes, and environmentally friendly plastics such as nylons that use castor oil as a primary component. 

Rechargeable lithium-ion polymer cells incorporate the polymer as part of the electrochemical operation of the battery and these cells are widely used to power such portable consumer products as laptop computers and mobile phones. Lithium-metal-polymer is a relatively new technology from Avestor in Canada. It uses a solid polymeric electrolyte obtained by dissolving a lithium salt in an appropriate co-polymer. The metallic oxide cathode is made from a plastic composite material. 

In Japan Kawasaki Steel has developed a new type of carbon filler for use in the plastic separators of fuel cells. It has been obtained by npgrading the company s mesocarbon microbeads used in lithium-ion rechargeable batteries. 

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