4 Chapter 1 electrification, such as GPS, advanced radio, and navigation systems, all require greater levels of power. Greater levels of vehicle to vehicle communications and autonomous vehicles will also require high levels of electrification. More battery technology also enables greater optimization of the engine by transferring these parasitic loads from the engine to the battery, which in turn allows for more engine downsizing. Yet today most electrically based vehicles are still based on architectures that were designed for internal combustion engines.
In fact, in most of these vehicles, there is no standard location for a battery, which is why we see so many different installation locations within different vehicles. Today, with only minor exceptions, most electrically powered vehicles package their batteries under the seats, in the trunk, or in the transmission tunnel—in essence, trying to fit the square peg of a battery into the round hole of the existing vehicle architecture. Future vehicles will be designed with the battery as one of the design criteria so it will be an integral part of the vehicle architecture rather than being added as an afterthought.
Purpose of the Book With all of these challenges in automotive and other energy storage applications, it is becom- ing more challenging to find a common means to discuss them. This book is intended to help bridge that gap by answering questions such as: What is the difference between a power battery and an energy battery? What is the difference between different Li-ion cell chemis- tries? Should the pack be liquid or air-cooled? What is a battery management system (BMS) and what does it do? These are the types of questions that this book will try to answer. Will this qualify you to be a battery engineer when you are done?
Definitely not, but will it prepare you to ask the right questions and have a solid understanding of the topic? Absolutely. Throughout the book I will attempt to use some analogies to correlate the terms and concepts that are used here to make them more easily understandable. For instance, we may think of the term energy, usually measured in kilowatt hours (kWh), in terms of being analogous to the size of a gas tank. So when we are speaking about the energy of a battery, we are talking about how much energy that battery “tank” holds.
I will use many examples from the automotive field to demonstrate the principles and con- cepts discussed here but remember that all of these concepts apply to a much wider variety of uses and applications. In Chapter 15, Li-ion Battery Applications, we will take a very wide look at the different examples of Li-ion batteries in a wide variety of applications ranging from e-bikes to electrified vehicles to forklifts, buses and stationary energy storage. Li-ion batteries more than many other subsystems in the vehicle, require a “systems”-level approach to engineering and design.
Battery pack engineering begins with the chemistry that happens at the cell level, then includes the electrical performance of both the cell and the