Lithium-polymer technology

Solid polymer and gel polymer electrolytes could be viewed as the special variation of the solution-type electrolyte. In the former, the solvents are polar macromolecules that dissolve salts, while, in the latter, only a small portion of high polymer is employed as the mechanical matrix, which is either soaked with or swollen by essentially the same liquid electrolytes. One exception exists molten salt (ionic liquid) electrolytes where no solvent is present and the dissociation of opposite ions is solely achieved by the thermal disintegration of the salt lattice (melting). Polymer electrolyte will be reviewed in section 8 ( Novel Electrolyte Systems ), although lithium ion technology based on gel polymer electrolytes has in fact entered the market and accounted for 4% of lithium ion cells manufactured in 2000. On the other hand, ionic liquid electrolytes will be omitted, due to both the limited literature concerning this topic and the fact that the application of ionic liquid electrolytes in lithium ion devices remains dubious. Since most of the ionic liquid systems are still in a supercooled state at ambient temperature, it is unlikely that the metastable liquid state could be maintained in an actual electrochemical device, wherein electrode materials would serve as effective nucleation sites for crystallization. 

The solid polymer electrolyte approach provides enhanced safety, but the poor ambient temperature conductivity excludes their use for battery applications. which require good ambient temperature performance. In contrast, the liquid lithium-ion technology provides better performance over a wider temperature range, but electrolyte leakage remains a constant risk. Midway between the solid polymer electrolyte and the liquid electrolyte is the hybrid polymer electrolyte concept leading to the so-called gel polymer lithium-ion batteries. Gel electrolyte is a two-component system, viz., a polymer matrix... 

Scale-up from laboratory test cells to EV module is the next challenge for the LPB technology. There are three general areas which need to be addressed when considering scale-up, namely (1) raw materials, (2) component fabrication, and (3) cell and battery construction. In general, the raw materials employed in the various forms of lithium polymer batteries can easily be obtained in large quantities. The key areas are the lithium metal foil and the active positive material. Lithium metal foils are commercially available in a range of thicknesses down to 50 pm. However, thinner... 

Stula et al 15] have reported the advanced battery technologies in the USA. Nickel-metal hydride, lithium ion, lithium polymer batteries and ultracapacitors have attracted an attention and been under development. 

Even with the current technology the lithium polymer batteries represent the state of the art in the field of electric energy storage systems, since they are characterized by very interesting values of the basic electrochemical parameters, as already reported in Table 1.8 in comparison with other batteries today available. 

Work at Harwell has concentrated on scaling up the lithium polymer battery technology for use in electric vehicle traction batteries. The project, supported by the Commission of the European Communities, has systematically scaled up the cell active area. The various cell sizes are shown in Figure 6.33. The larger cells were used to construct two 80 A h units which are shown in Figure 6.34. The results of the project have highlighted the need for capacity balance and excellent cell-to-cell reproducibility. 

This enterprise is an advanced lithium polymer battery innovator and manufacturer. Divisions include clean transportation, consumer products and more. Electrovaya claims to have >150 global patents on its Lithium Ion SuperPolymer battery technology and associated system technologies. SuperPolymer is basically a novel nanostructured lithium-ion polymer technology platform. It enables more energy to be stored in a smaller space applications are smaller, lighter and more powerful. 

Kokam is a very dedicated Korean manufacturer founded in 1989. Kokam possesses its own unique, proprietary technology (the Superior Lithium Polymer Battery, or SLPB), which has proven marketability over the existing and perceived competition. They offer batteries for transportation, defense and industrial application. All their battery systems are based on nickel—manganese—cobalt (NMC) lithium-ion cells. They are the battery supplier for Land Rover, Mercedes, Lotus and MotoCzysz (electric motor bikes). 

Even in the case of communication apparel, autonomy versus weight and volume is once again a compromise that must be made. Battery technologies evolve, for example, lithium polymer, but unfortunately the batteries are still often the heaviest part of portable devices. The advantage of communication apparel is that the weight distribution in clothing will make it possible to be freed partly from this constraint. 

To begin with (in the mid-1970s ), the positive electrode was made of intercalation materials such as TiS2 (titanium disulfide) whose lamellar structure contained inserted lithium, the negative electrode being made simply of metal lithium, with the difficulties inherent to that electrode, which we shall recap below. These difficulties remain with lithium-metal polymer technology as described in Chapter 8. 

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