66 Chapter 7 energy that operates by converting chemical energy into electrical energy. Linden and Reddy (2011, p. 1.3) define a battery as: a device that converts the chemical energy contained in its active materials directly into electric energy by means of an electrochemical oxidation-reduction (redox) reaction.
Essentially what Linden and Reddy’s (2011) definition means is that when a current is applied to the cell, a chemical reaction occurs between the anode and cathode inside the battery cell, whereby lithium-ions (anions) flow between the anode and cathode through the electrolyte thus generating an electrical current which can be converted into “work” (power) for various applications. The battery is unique in energy storage solutions in that it both generates the energy and stores it within the same device.
This makes the electrical battery somewhat unique in the energy storage applications where virtually all other applications generate the energy somewhere else and the storage device does only that, stores the energy. For example, liquid gasoline and diesel, compressed natural gas, liquid propane gas, com- pressed hydro, compressed air, and other similar technologies are examples of energy that is created in one place and then stored in another and used to generate power in yet another place.
In the internal combustion engine, for example, gasoline is stored in a tank, then is pumped into a fuel injection unit (or a carburetion device) where it is then burned to create energy (power) to move the cylinders. Different battery types have different performance characteristics and are therefore appropri- ate for different types of applications. In Table 1 , nonlithium-based chemistries, several of the most common nonlithium-based chemistry types are compared. The table is not all-inclusive but offers a good summary of some of the major nonlithium chemistries that are being used in ESSs.
For example, traditional lead acid offers the shortest cycle life and lowest energy density but also offers the lowest cost. Secondary battery chemistries such as lead acid, nickel cadmium (NiCd), NiMh, sodium sulfur, and sodium nickel chloride are or were used in many of the early automotive electrification attempts. In fact, today NiMh is still the best selling battery chemistry for hybrid electric vehicles (HEVs). In the sections that follow, we will take a brief look at these chemistries in a bit more detail. Lead Acid Lead acid (PbA, LA, or LAB) is one of the oldest and most commonly used chemistries in energy storage applications today.
Lead acid is a reliable power battery but suffers from low cycle life only achieving 300–500 cycles in the standard lead acid battery. Lead acid batteries take their name from the combination of lead plates that form the anode and cathodes and the sulfuric acid electrolyte in which they are immersed. Today lead acid is the standard battery used in engine starting, lighting and ignition (SLI) applications due to its high power capabil- ity. Early electric vehicles (EVs) also used lead acid as it was the most readily available and cheapest battery on the market. Lead acid is also still commonly used in backup stationary