Cells thin prismatic

The loss of capacity with storage at different temperatures is also shown in Fig. 24.30. As with all lead-acid batteries, they should be recharged when the charge retention is below 50%. The cycle life of the thin prismatic batteries is similar to the one shown for the VRLA cells in Fig. 24.27. 

FIGURE 24.28 Characteristic discharge curves for thin prismatic single-cell sealed lead-acid batteries at 20°C. Courtesy of Portable Energy Products, Inc.)... 

The thin prismatic batteries are designed to meet the needs of compact equipment. The rectangular shape permits more efficient battery assembly, eliminating the voids that occur with the assembly of cylindrical cells. The volumetric energy density of the battery can be increased by a factor of about 20%. The prismatic ceUs also offer more flexibility in the design of batteries, as the battery footprint is not controlled by the diameter of the cylindrical cell. 

Various geometries of LPBs, including a flat thin design for smart credit cards, prismatic packaging for portable computers, C-size cylindrical cells for consumer electronic devices and high capacity cylindrical, spiral... 

The thin-layer cell used in SNIFTIRS experiments is essentially the same as that used in EMIRS. However, Pons and co-workers [92] (SNIFTIRS), Bewick et al. [53] (EMIRS), and Kunimatsu and co-workers [94] (using the IRRAS technique) have all employed prismatic CaF2 windows with 65° bevelled edges [see Fig. 39(b)]. There are two main advantages of this arrangement. 

As already stated in 5 a (p. 467) coacervates in general wet the celloidin membranes of the prismatic cells. This also holds for the coacervate which is produced after accumulation of a basic dye (for example toluidine blue) in the cell compartments filled with gum arabic sol. In the final state it wets the cell walls and lies spread out in a thin layer over them. ... 

The unit cell production for 2005 by product application is given in Table 1.4. Cellular phone applications dominate the unit cell production. The thin, rectangular polymer/laminate cell construction has found favor in the cellular phone market and now accounts for about 13%, with the rest being the prismatic cell sizes. Notebook computers are second followed by cameras. 

Once wound, the jellyroll is inserted into a can and fiUed with electrolyte. The separator must be wetted quickly by the electrolyte to reduce the electrolyte filling time. A header is then crimped into the cell to cover the can from top. In some prismatic cells, the jellyroll is pressed at high temperatures and pressures and then inserted into thin rectangular cans. A typical 18,650 Li-Ion cell use around 0.07-0.09 m of separator, which is approximately 4-5% of the total cell weight. ... 

A related Li ion cell type is the Li ion polymer cell that uses a polymer gel electrolyte. Li ion polymer cells are often designed as flat prismatic cells and can be made quite thin. 

The small sealed sintered plate Ni-Cd cylindrical and prismatic cell constructions have the favorable characteristics of the pocket/tubular plate constructions with increased energy density. The electrodes are thin and the cells have low internal resistance with excellent high rate and low temperature performance. The stem is rugged and can withstand physical and electrical abuse. It requires minimal maintenance. 

Cap-XX — Founded in 1997, Cap-XX focuses on thin, flat, single or dual (prismatic) cells that produce short term high power required for pulse... 

At a larger order of size, enamel has a prismatic structure, the enamel prism or rod representing the most obvious histologically defined entity. In cross-section its dimensions are approximately the same as those of an ameloblast but it is extremely long and may extend from the amelodentinal junction to the enamel surface. Adjacent prisms are approximately parallel but show local changes of direction. The prisms are formed as the result of the activity of ameloblasts, and one ameloblast may contribute to several prisms, while each prism receives material from more than one cell. In the outermost layer of fully formed human enamel the prisms merge into each other and a thin surface layer is produced. This layer resembles reptile enamel which is less than 1 mm thick and is not prismatic but continuous. 

Most primary or dry cells with aqueous electrolytes employ single, thick electrodes arranged in parallel or concentric configurations. Typical battery configurations are categorized as cylindrical, bobbins, buttons, or coin cells. Some primary cells are made in prismatic and thin, flat constructions to achieve the lowest volume. These form factors yield poor energy density and power capacity levels. 

Thin flat prismatic sealed lead-acid cells have been designed for portable applications as they offer more flexibility in the design of the battery. They use space more efficiently than cylindrical cells, resulting in a higher volumetric energy density, and the slim design is adaptable to small-footprint equipment. " An exploded view of a typical flat cell is shown in Fig. 24.5. 

Another potential advantage of the solid polymer battery is that the design lends itself to manufacture by automatic processes and the capability to be easily fabricated in a variety of shapes and forms. Very thin batteries for cell phones, PDAs and similar applications can be manufactured. At the other extreme, large thin plates can be manufactured and assembled in multiplate prismatic or bipolar batteries. 

Since the commercialization of Li-ion batteries by Sony in 1990, a broad array of variants has been introduced. One type, gel-polymer Li-ion batteries, utilizes the same active materials as products that employ liquid electrolytes, but in a different construction that enables the fabrication of cells with a thin form factor. Gel-polymer batteries, also referred to as polymer Li-ion batteries in the marketplace, are products where the microporous separator film used in conventional batteries is substituted by a layer of PVDF-HFP, or other polymer, impregnated with liquid electrolyte and the solid current collector foil is typically substituted with an open expanded metal current collector grid. In gel-polymer cells, the positive, separator, and negative layers are bound by the polymer, typically PVDF-HFP, and can be laminated together to form a monolithic device. Despite these differences, the active cell chemistry may remain identical to that in cylindrical or prismatic Li-ion batteries. 

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