CHAPTER 4 Battery Pack Design Criteria and Selection Perhaps one of the most challenging and frightening aspects of battery design, especially for the non-engineer, is trying to make the initial calculations around a new battery solution. However, there are a few relatively simple calculations that can be made that will allow you to appropriately size a battery concept for your application. The first thing that must be understood is that a lithium-ion battery pack is a system of interrelated subsystems that are all necessary to make the battery pack function and meet its life requirements. At the core of the pack are the lithium-ion cells.
The amount of cells will vary from one application to another, but every battery pack will require a group of cells connected in different ways in order to achieve the voltage and energy desired. In order to “hold” and manage the cells a mechanical structure is put in place. This mechanical system will include both some way to connect and hold the cells as well as the overall enclosure ( Figure 1 ). Within this enclosure, you will also find the battery management system (BMS). The BMS is an electronic controller that monitors and manages all of the functions of the battery opera- tion.
The BMS may also have separate electronics installed at the cell or module level which monitor the temperature and voltage of the cells, often referred to as a voltage temperature Figure 1 A123 lithium-ion battery exploded view. The Handbook of Lithium-Ion Battery Pack Design. http://dx.doi.org/10.1016/B978-0-12-801456-1.00004-X Copyright © 2015 Elsevier Inc. All rights reserved. 35