Battery selection process

The process from concept, to design, to product may be accomplished, a number of ways, but current professional practice uses systems engineering (Fig. 11.1), which is a method whereby requirements are cascaded to subtasks and then to a series of validations based on a methodical review of the design. It is a process that emphasizes engineering up-front, but in a cyclic way, which is internally and 

Engineering Director High level vehicle requirements Provide budget Provide headcount Provide facilities Participate in design reviews 

Recruit and manage allocated resources to meet vehicle requirements 

Participate in design reviews Sign-off on battery Vehicle development timing plan — battery dates 

Technical Specialists Provide expertise Analysis of problems 

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Table ILL Roles and responsibilities in the automotive battery selection process.

As discussed, BR and CR lithium batteries are most ideal for applications in which longevity, fluctuating duty-cycle requirements, and high dynamic bandwidth are the major performance requirements. Dynamic physical parameters include variations in temperature, output impedance, duty cycle, and battery energy capacity, which affect the battery-loading conditions and ultimately shape the battery-selection process. These lithium-based batteries are most suitable to operate over high-dynamic-bandwidth physical parameters. 

In conclusion, it can be said regarding the battery selection process, whether primary or secondary batteries are being considered, that the design engineer is faced with many commercial portable power systems in a wide variety of models. The battery selection process cannot therefore be reduced to an exact science. Seldom does any one battery system meet all the requirements Ta a given application. The selec-lion of a battery is further complicated by the fact that the performance characteristics of battery systems vary with temperature, current drain, service schedules, etc. Consequently the selection process usually involves a trade-off or compromise between battery requirements and battery system characteristics. 

Only a few of the thousands of proprosed battery systems have been commercialized. A set of criteria can be established to characterize reactions suitable for use in selecting chemical systems for commercial battery development. Very few combinations can meet all of the criteria for a general purpose power supply. The fact that two of the major battery systems introduced more than 100 years ago, lead acid (rechargeable) and zinc—manganese dioxide (primary), are still the major systems in their category is indicative of the selection process for chemical reactions that can serve the battery marketplace. 

To guide the reactor selection process, Walas [7] has classified reactions according to the operating mode (batch or continuous), reactor type (tank, tank battery, tubular), flow type (back mixed, multistage back mixed), and the phases in contact. This reactor classification in Table 7.2 indicates if a particular reactor arrangement is commonly used, rarely used, or not feasible. 

Batteries are first loaded via a bunker onto a band conveyor where block batteries, battery packs and non-battery waste are removed and sorted by hand. The batteries selected at this stage are those which are unable to be passed through the electromagnetic sensors in stage IV of the process. These include rechargeable battery packs and industrial batteries. 

As seen fix>m the process flowsheets there are many possible entry points for raw materials. This provides flexibility, as well as complexity, to the acquisition of raw materials. The list of input materials contains not only base metal concentrates but also semi-finished products such as unrefined lead bullion, and process by-products such as dust or sludge from other companies. Recycling of consumer products is also an important factor in feed material selection because Cominco has a strong commitment to environmental stewardship, as reflected by the quantity of lead battery products processed annually. 

Another key battery component is the electrolyte. While many possible electrolytes are being developed, we have selected lithium hexafluorophosphate (LiPFe) in a solvent of EC and DMC. Little information exists on the production of LiPFe, so its impact, although estimated on the basis of data presented by Espinosa et al. [12], is somewhat uncertain. Given the potentially harmfiil nature of the compound, it is of interest to consider what its fate may be during the battery recycling process, which we address in Section 4. 

Since different active materials nsed in lithium-ion cells have very different responses to the cell s abnse, the materials selection is crucial from the battery safety and performance point of view. The battery design process usually starts from the selection of cell chemistry and then the safety of the system is analytically determined from the snnunary contribution of the individual components. Chapter 1 presented an introdnction to the constituents of the lithium-ion cell the anode, cathode, separator, and electrolyte. This chapter will discuss safety impact of these components, as well as the internal cell protection devices. A discussion of the selected options of the cell design and packaging (e.g., cell aspect ratio) in terms of thermal and safety properties will be also included. The chapter will conclude with examples of single cell and cell pack safety testing. 

The devil is the in the details, and the choice of materials compatibility is insufficient to match a separator system to a battery chemistry. In this section we will briefly outline design issues and their solutions to a few different chemistries. This is intended to serve as guiding examples for the reader s own selection process of a separator material and system design. 

Because of the varying performance characteristics of battery systems under different conditions, it is virtually impossible to select the battery best suited for a particular application. In selecting the proper battery for a specific application, the designer should consult battery specialists for assistance early in the design process. Since the battery is an integral part of the electrical system, unwarranted and costly compromises may be avoided by coordinating battery selection and product design. 

Solid mixed ionic-electronic conductors (MIECs) exhibit both ionic and electronic (electron-hole) conductivity. Naturally, in any material there are in principle nonzero electronic and ionic conductivities (a i, a,). It is customary to limit the use of the term MIEC to those materials in which a, and 0, 1 do not differ by more than two orders of magnitude. It is also customary to use the term MIEC if a, and Ogi are not too low (o, a i 10 S/cm). Obviously, there are no strict rules. There are processes where the minority carriers play an important role despite the fact that 0,70 1 exceeds those limits and a, aj,i< 10 S/cm. In MIECs, ion transport normally occurs via interstitial sites or by hopping into a vacant site or a more complex combination based on interstitial and vacant sites, and electronic (electron/hole) conductivity occurs via delocalized states in the conduction/valence band or via localized states by a thermally assisted hopping mechanism. With respect to their properties, MIECs have found wide applications in solid oxide fuel cells, batteries, smart windows, selective membranes, sensors, catalysis, and so on. 

Ionic liquid solvents are non-volatile and non-toxic and are liquids at ambient temperature. Originally, work was concerned with battery electrolytes. These ionic liquids (IL) show excellent extraction capabilities and allow catalysts to be used in a biphasic system for convenient recycling (Holbrey and Seddon, 1999). IFP France has commercialized a dimerization process for butenes using (LNiCH2R ) (AlCU) (where L is PRj) as an IL and here the products of the reaction are not soluble in IL and hence separate out. The catalyst is very active and gives high selectivity for the dimers. 

The problems relating to mass transfer may be elucidated out by two clear-cut yet different methods one using the concept of equilibrium stages, and the other built on diffusional rate processes. The selection of a method depends on the type of device in which the operation is performed. Distillation (and sometimes also liquid extraction) are carried out in equipment such as mixer settler trains, diffusion batteries, or plate towers which contain a series of discrete processing units, and problems in these spheres are usually solved by equilibrium-stage calculation. Gas absorption and other operations which are performed in packed towers and similar devices are usually dealt with utilizing the concept of a diffusional process. All mass transfer calculations, however, involve a knowledge of the equilibrium relationships between phases. 

Both batteries and fuei cells utilize controlled chemical reactions in which the desired process occurs electrochemically and all other reactions including corrosion are hopefully absent or severely kinetically suppressed. This desired selectivity demands careful selection of the chemical components including their morphology and structure. Nanosize is not necessarily good, and in present commercial lithium batteries, particle sizes are intentionally large. All batteries and fuel cells contain an electropositive electrode (the anode or fuel) and an electronegative electrode (the cathode or oxidant) between which resides the electrolyte. To ensure that the anode and cathode do not contact each other and short out the cell, a separator is placed between the two electrodes. Most of these critical components are discussed in this thematic issue. 

Electrochemistry can be broadly defined as the study of charge-transfer phenomena. As such, the field of electrochemistry includes a wide range of different chemical and physical phenomena. These areas include (but are not limited to) battery chemistry, photosynthesis, ion-selective electrodes, coulometry, and many biochemical processes. Although wide ranging, electrochemistry has found many practical applications in analytical measurements. The field of electroanalytical chemistry is the field of electrochemistry that utilizes the relationship between chemical phenomena which involve charge transfer (e.g. redox reactions, ion separation, etc.) and the electrical properties that accompany these phenomena for some analytical determination. This new book presents the latest research in this field. 

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