Chapter 9 - Rechargeable Batteries and Their Management

Abstract

The demand for smaller, lightweight, portable electronic equipment has dramatically increased the need for research on rechargeable (or secondary) battery chemistries. In addition to achieving improved performance on lead acid and nickel cadmium (NiCd) batteries, many new chemistries such as nickel metal hydride (NiMH), lithium ion (Li-ion), rechargeable alkaline, silver-zinc, zinc-air, and lithium polymer have come up. Higher energy density, superior cycle life, environmental friendliness, and safe operation are among the general design targets of battery manufacturers. To complement these developments, many semiconductor manufacturers have introduced new integrated circuit families to achieve the best charge/discharge performance and the longest possible lifetime from battery packs. This chapter describes the characteristics of battery families such as sealed lead acid, NiCd, NiMH, Li-ion, rechargeable alkaline, and zinc-air together with modern techniques used in battery management ICs. The old concept of battery management meant a reliable, fast, and safe charging methodology for a battery bank, together with the monitoring facilities to detect the discharge condition of the battery pack. The attributes of a modern battery management system must include battery charging methods and charge control, and end of discharge determination. The objective of fast charging a battery is to cram as much energy as it takes to bring the battery back to fully charged state in the shortest possible time, without damaging the battery or permanently affecting its long-term performance.