Rechargeable cylindrical

The manufacturing lines for the production of rechargeable cylindrical cells are nearly identical with those of the low-cost primary cell version. This is an important cost-determining factor [17]. 

The packaging approach utilized for tliis battery is similar to that for nickel—hydrogen single cylindrical cells as shown in Figure 23. The sdv er electrode is typically the sintered type used in rechargeable sdv er—zinc cells. The hydrogen electrode is a Teflon-bonded platinum black gas difhision electrode. 

Secondary lithium-metal batteries which have a lithium-metal anode are attractive because their energy density is theoretically higher than that of lithium-ion batteries. Lithium-molybdenum disulfide batteries were the world s first secondary cylindrical lithium—metal batteries. However, the batteries were recalled in 1989 because of an overheating defect. Lithium-manganese dioxide batteries are the only secondary cylindrical lithium—metal batteries which are manufactured at present. Lithium-vanadium oxide batteries are being researched and developed. Furthermore, electrolytes, electrolyte additives and lithium surface treatments are being studied to improve safety and recharge-ability. 

Figure 2. Section through a cylindrical AA-size alkaline Mn02-Zn cell. Primary cells and the rechargeable cells discussed later have same construction and differ only in separator type, electrode compositions, and cathode / anode balance. (Reproduced by courtesy of Battery Technologies, Inc.).

Nickel-cadmium sealed cells are now a commercially important consumer product. They find use, both as button and cylindrical cells, in portable cordless appliances such as power tools, electric razors and photoflash apparatus, and increasingly in hybrid mains/battery equipment such as portable tape recorders, radios and television receivers. Many of these cells are readily interchangeable with primary batteries. In recent years, advances in design have increased recharge rates cylindrical cells with sintered electrodes can now be fast charged from full discharge at up to the C/l rate of 80% of capacity. 

Fig. 7.29 Construction of a C(coke)-LiCo02 cylindrical rechargeable cell. (By permission of Sony Energytech.)...

In the consumer sector uses for primary nonaqueous batteries include button or coin cells for watches, calculators and other small devices with relatively low power requirements. Larger cylindrical and prismatic rechargeable consumer-oriented nonaqueous batteries are essentially all based on a Li or, most frequently, Li-ion negative electrode technology and are increasingly widely used in many portable electronic devices. 

The recent example of the ab initio structure determination of the polymer electrolyte Poly (ethylene oxide)6 LiAsFe by Bruce et is a notable example of the complex structures that can be determined from powder diffraction on a pulsed neutron source. Polymer electrolytes consist of salts dissolved in solid high molecular weight polymers, and represent a unique class of solid coordination compounds. Their importance lies in their potential in the development of truly all-solid-state rechargeable batteries. The structure of the 6 1 complex is particularly important, as it is a region where the conductivity increases markedly. The structure of the complex is distinct from all known crystal structures of PEO salt complexes (see Figure 7). The Li-i- cations are arranged in rows, with each row located inside a cylindrical surface formed by two PEO chains, with the PEO chains adopting a previously unobserved conformation. Furthermore the anions are located outside the PEO cylinders and are not coordinated with the cations. 

The AMF, with guidance from Jet Propulsion Lab (JPL), developed a small cylindrical lithium ion rechargeable battery. A new company (QuaUion, Inc.) was formed and financed by Alfred Mann to manufacture and improve these unique highly reliable batteries. Today, these batteries can be safely recharged if discharged to zero volts and are expected to operate for over 10 years. These batteries were designed specifically for the BPB (Figure 34.2). 

Lithium ion cells serve the smaU-sealed rechargeable battery market and compete mainly with the Ni-Cd and Ni-MH cells for the various applications. The Li-Ion cells are available in cylindrical and prismatic format as well as flat plate constructions. The cylindrical and prismatic constructions use a spiral-wrap cell core where the ceU case maintains pressure to hold and maintain compression on the anode, separator, and cathode. The lighter-weight polymer constructions utilize the adhesive nature of a polymer/laminate-based electrolyte to bond the anode to the cathode. 

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