Energy Storage

Frontmatter

Chapter 1. Introduction

Abstract

Concern about the inevitable depletion of the fossil fuels that are now the major sources of energy has been greatly reduced, due to the recent development of fracking technology, as described in the Preface, and which will be further discussed in Chap. 23. However, there is another matter that is very important in considering the effective use of the energy that is available. This involves the relationships between the several types of energy, and also the various different uses of energy.

Robert A. Huggins

Chapter 2. General Concepts

Abstract

This book is about energy, and various mechanisms by which it can be stored for use at a later time, for a different purpose, or at a different place.

Robert A. Huggins

Chapter 3. Thermal Energy Storage

Abstract

It was mentioned in Chap. 1 that a significant portion of the total energy use is for temperature control and lighting in living and working spaces. Energy use for lighting purposes comprises between 20 and 50 % of the total energy used in homes, and varies appreciably with both location and time of the year, of course. This is expected to decrease substantially as the result of the use of fluorescent and light-emitting-diode (LED) devices in the future.

Robert A. Huggins

Chapter 4. Reversible Chemical Reactions

Abstract

In the discussion of thermal energy storage in Chap. 3, it was pointed out that energy can be stored in both the sensible heat that is related to changes in the temperature of materials and their heat capacities, and the latent heat involved in isothermal phase transitions. A common example of such an isothermal phase transition with a significant amount of stored heat is the melting and freezing of water. In such cases, there are no changes in chemical composition. The chemical species below and above the phase transition are the same. Only their physical state is different. Such reactions are said to be congruent.

Robert A. Huggins

Chapter 5. Energy Storage in Organic Fuels

Abstract

The Preface included a discussion of the several types of natural materials that can be obtained from the earth and used as fuels. The major ones are wood and the several fossil fuels, including the various types of coals, crude oil, and natural gas. The fossil fuels, which now play such a major role in the energy supply, will surely gradually become less important as they become depleted. But the recent development of fracking technology, as discussed in the Preface, will result in the access to substantial additional sources of crude oil in some locations.

Robert A. Huggins

Chapter 6. Mechanical Energy Storage

Abstract

There are two basic types of energy storage that result from the application of forces upon materials systems. One of these involves changes in potential energy, and the other involves changes in the motion of mass, and thus kinetic energy. This chapter focuses upon the major types of potential energy and kinetic energy storage. It will be seen that it is possible to translate between these two types of energy, as well as to convert these energies to heat or work.

Robert A. Huggins

Chapter 7. Electromagnetic Energy Storage

Abstract

Several of the prior chapters in this text have shown that there is a wide range of energy storage needs with widely different time periods; some involve seasonal, weekly, and daily cycles, and others require energy intermittently, sometimes over much shorter time periods. A variety of different technologies are employed to meet these various requirements.

Robert A. Huggins

Chapter 8. Hydrogen Storage

Abstract

Hydrogen is an important energy carrier, and when used as a fuel can be considered to be an alternate to the major fossil fuels, coal, crude oil and natural gas, and their derivatives. It has the potential to be a clean, reliable and affordable energy source, and has the major advantage that the product of its combustion with oxygen is water, rather than CO and CO₂, which contain carbon and are considered greenhouse gases. It is expected to play a major role in future energy systems.

Robert A. Huggins

Chapter 9. Introduction to Electrochemical Energy Storage

Abstract

Among the various methods that can be used for the storage of energy that are discussed in this text, electrochemical methods, involving what are generally called batteries, deserve the most attention. They can be used for a very wide range of applications, from assisting the very large scale electrical grid down to tiny portable devices used for many purposes. Battery-powered computers, phones, music players, etc. are everywhere, and one of the currently hot topics involves the use of batteries in the propulsion of vehicles, hybrid autos, plug-in hybrids, and fully electric types.

Robert A. Huggins

Chapter 10. Principles Determining the Voltages and Capacities of Electrochemical Cells

Abstract

In the prior chapter it was shown that the fundamental driving force across an electrochemical cell is the virtual chemical reaction that would occur if the materials in the two electrodes were to react with each other. If the electrolyte is a perfect filter that allows the passage of ionic species, but not electrons, the cell voltage when no current is passing through the system is determined by the difference in the electrically neutral chemical compositions of the electrodes. The identity and properties of the electrolyte and the phenomena that occur at the electrode/electrolyte interfaces play no role. Likewise, it is the properties of the electrodes that determine the capacity of an electrochemical cell.

Robert A. Huggins

Chapter 11. Binary Electrodes Under Equilibrium or Near-Equilibrium Conditions

Abstract

The theoretical basis for understanding and predicting the composition dependence of the potentials, as well as the capacities, of both binary (two element) and ternary (three element) alloys has now been established. The relevant principles are discussed for the case of binary systems in this chapter. Ternary systems will be treated in the next chapter.

Robert A. Huggins

Chapter 12. Ternary Electrodes Under Equilibrium or Near-Equilibrium Conditions

Abstract

The previous chapter described binary electrodes, in which the microstructure is composed of phases made up of two elements. It was pointed out that there are also cases in which three elements are present, but only partial equilibrium can be obtained in experiments, so the electrode behaves as though it were composed of two, rather than three, components.

Robert A. Huggins

Chapter 13. Potentials

Abstract

Potentials and potential gradients are important in battery systems. The difference in the potentials of the two electrodes determines the voltage of electrochemical cells, being larger when they are charged, and smaller when they are discharged. On the other hand, potential gradients are the driving forces for the transport of species within electrodes.

Robert A. Huggins

Chapter 14. Insertion Reaction Electrodes

Abstract

The topic of insertion reaction electrodes did not even appear in discussions of batteries and related phenomena just a few years ago, but is a major feature of some of the most important modern battery systems today. Instead of reactions occurring on the surface of solid electrodes, as in traditional electrochemical systems, what happens inside the electrodes is now recognized to be of critical importance.

Robert A. Huggins

Chapter 15. Electrode Reactions That Deviate from Complete Equilibrium

Abstract

The example that was discussed earlier, the reaction of lithium with iodine to form LiI, dealt with elements and thermodynamically stable phases. By knowing a simple parameter, the Gibbs free energy of formation of the reaction product, the cell voltage under equilibrium and near-equilibrium conditions can be calculated for this reaction. If the cell operates under a fixed pressure of iodine at the positive electrode and at a stable temperature, the Gibbs phase rule indicates that the number of the residual degrees of freedom F in both the negative and positive electrodes is zero. Thus the voltage is independent of the extent of the cell reaction in both cases.

Robert A. Huggins

Chapter 16. Primary, Non-rechargeable Batteries

Abstract

Except for the discussions of the lithium/iodine cell in Chap. 10, all of the discussion concerning batteries for energy storage has been oriented toward understanding the properties of individual cell components and systems. The emphasis has been upon those that are most interesting for use in rechargeable batteries.

Robert A. Huggins

Chapter 17. Lead-Acid Batteries

Abstract

Over many years, the most common use of the word “battery” was in connection with the rechargeable energy source that was used to start automobiles. These were almost always what are generally called Pb-acid batteries, and were often a source of aggravation. A considerable amount of progress has been made in recent years, so that the SLI (starting-lighting-ignition) batteries now used in autos are actually quite reliable, assuming that they are not abused. Different types of Pb-acid batteries are used for a number of other applications, both mobile and stationary, and ranging from quite small to very large. The greatest fraction of the total battery market worldwide is now based upon this technology.

Robert A. Huggins

Chapter 18. Negative Electrodes in Other Rechargeable Aqueous Systems

Abstract

This chapter discusses two examples of negative electrodes that are used in several aqueous electrolyte battery systems, the “cadmium” electrode and metal hydride electrodes.

Robert A. Huggins

Chapter 19. Positive Electrodes in Other Aqueous Systems

Abstract

This chapter discusses three topics relating to positive electrodes in aqueous electrolyte battery systems, the manganese dioxide electrode, the nickel electrode and the so-called memory effect that is found in batteries that have “nickel” positive electrodes.

Robert A. Huggins

Chapter 20. Negative Electrodes in Lithium Systems

Abstract

A great deal of attention is currently being given to the development and use of batteries in which lithium plays an important role. Looked at very simply, there are two major reasons for this. One is that lithium is a very electropositive element, and its employment in electrochemical cells can lead to larger voltages than are possible with the other, less electropositive alkali metals. The second positive aspect of lithium systems is the possibility of major reductions in weight, at least partly due to the light weight of elemental lithium and many of its alloys and compounds.

Robert A. Huggins

Chapter 21. Positive Electrodes in Lithium Systems

Abstract

Several types of lithium batteries are used in a variety of commercial products, and are produced in very large numbers. According to various reports, the sales volume in 2008 is approximately 10 billion dollars per year, and it is growing rapidly. Most of these products are now used in relatively small electronic devices, but there is also an extremely large potential market if lithium systems can be developed sufficiently to meet the requirements for hybrid, or even plug-in hybrid vehicles.

Robert A. Huggins

Chapter 22. Energy Storage for Medium- to Large-Scale Applications

Abstract

Most of the highly visible applications of advanced energy storage technologies are for relatively small applications, such as in portable computers or implanted medical devices, where the paramount issue is the amount of energy stored per unit weight or volume, and cost is not always of prime importance. Such energy storage components and systems have occupied much of the attention in this text, especially the later chapters related to electrochemical cells and systems.

Robert A. Huggins

Chapter 23. Storage of Energy for Vehicle Propulsion

Abstract

Most vehicles are propelled by internal combustion motors that consume liquid fuels, either gasoline or diesel fuel. In those cases, the energy storage mechanism is a simple tank to hold the liquid fuel.

Robert A. Huggins

Chapter 24. A Look at the Future

Abstract

When considering what changes and new developments are possible, or even likely, in the years ahead, it is realistic to consider a quotation attributed to Thomas A. Edison:

Robert A. Huggins

Backmatter