Applied Embedded Electronics

Chapter 5. Battery Power

Modern electronics includes a multitude of mobile and portable devices, with the AC power cord relegated to battery charging. Battery power is a must-have for modern devices, and even plugged-in devices frequently have internal batteries to preserve critical systems when the power goes out.

Many device fires, product recalls, and explosions can be traced to improper battery system design. Also, many end users are frustrated by devices with insufficient battery capacity that can’t make it through a typical day of use. Clearly, there are a lot of marginal battery systems out there in need of improvement.

Most battery textbooks focus on the chemistry and physics of batteries, with few centered on how to incorporate batteries into an electrical design. In this book, chemistry discussions are minimal and batteries are primarily treated as a black box. Readers here are trying to design better circuits and systems, not create better batteries.

In this chapter, the emphasis is on designing a battery system to fit the needs of an electronic system and on the selection criteria and support materials required to make proper design decisions. As your design progresses, make sure you obtain the latest performance specifications of the devices you plan to use. Battery technology is evolving, and specifics need to be up to date.

Battery Basics: Definitions

Figure 5-1 shows the general structure of a single-cell battery that includes three distinct parts:

Anode

Electrical ...