Selecting the Right Battery System for Cost-Sensitive Portable Applications While Maintaining Excellent Quality

AN1088 Selecting the Right Battery System For Cost-Sensitive Portable Applications While Maintaining Excellent Quality BATTERY CHEMISTRIES Author: Brian Chu Microchip Technology Inc. There are three key attributes in a battery: 1. Energy Density (Size & Weight) INTRODUCTION 2. Charge/Discharge Cycles (Life Cycle) 3. Capacity (Operational duration without AC Portable electronic devices have played an important Adapter presence) role in a person's daily digital life and have changed the way people live and work. Commonly seen portable Like the most engineering works, the key attributes do electronic devices are Cellular Phone, Media Players, not exist in the same technology. There is always a Digital Camera, Digital Camcorder, Handheld GPS, trade-off between them. In today's portable world, the Digital Reader and PDA. With the emerging technolo- product life cycle is very short. Thus, the battery life gies that are available today, portable electronic cycle is a minimal concern for customers and manufac- designers are trying to integrate more features into turers. The operating duration, package size and over- thinner and smaller form-factors while maximizing the all system weight become the most important factors battery life. when selecting the battery chemistry for a portable application. Batteries are the main power source for portable electronic devices, and selecting a right battery system TABLE 1: BATTERY COMPARISONS 1 [8]for an unique application is one of the important factors in the portable electronic design process. It involves )selecting a battery chemistry and charge management ty ) gity Ls V) /K it / nsin (u hre eg hr -control circuitry. The battery life indicates the length a )- rc gDe n ))i D i Vy tay eCW (V (Vat (W gg g ( r er e gproduct can be used under portable mode. Longer ere ar g Volme n h age (ght ta di tta OpeluEnE COpen n e ol Chemistry ol EV W Vo V Volbattery life can simply make a portable device standout in the market automatically. This can usually be Alkaline 145 400 1.2 1.6 0.9 NA achieved by reducing system power consumption and SLA 30-40 2.0 2.25 1.75 2.850-80 implementing an advanced battery technology. When it comes to production, reliability, safety, low-cost NiCd 40-80 100-150 1.2 1.3 0.9 1.6 and easy installation are the important elements while NiMH 60-100 160-230 1.2 1.3 0.9 1.5maintaining good quality. Each battery chemistry has its advantage over another. This application note is Li-Ion 110-130 210-320 3.6 4.2 2.8 4.2 intended to assist portable electronic product designers and engineers in selecting the right chemistry for today's low cost portable applications with design TABLE 2: BATTERY COMPARISONS 2 [8] simplicity. The solutions are ideal for use in space-lim- ited and cost-sensitive applications that can also e g raccelerate the product time-to-market rate. e ) ha C) ? °) arg ( scm ) h % i ( g tc r. re e ge shlh ( uis inr - c te/D ota D nt n g a n ra har Cr a lf- t s mAca er alete ( ihis is