Battery Power - Winter 2014 - (Page 11)

When Rubber Stamping is Not Enough How to Make Batteries in Critical Devices More Reliable Isidor Buchmann, CEO and Founder Cadex Electronics, Inc. The approval process to release a new product is getting tougher. New rules are added that increase manufacturing costs and complicate logistics. Once approved and released, few rules apply that oversee continued reliability of the device; the agencies have done their job and the responsibility falls on the user. To assist in the regulatory approval, device manufacturers pick the best battery from the lot. This satisfies the present but ignores true field conditions. Little weight is placed on battery aging and no models exist that assure good reliability with a less than perfect battery. Reserve energy to support emergency situations is often ignored. Manufacturers account for some but the amount is not specified. Figure 1 suggests a 20 percent fade as part of a less than perfect but still usable battery and 20 percent for spare. This would bring the usable battery capacity from 100 percent to 60 percent, a requirement that is too stringent for most applications. Knowing when to replace a battery is an ongoing concern and date-stamping provides a partial solution. Device manufacturers support this method for obvious reasons; it sells batter- www.BatteryPowerOnline.com ies. However, date-stamping has flaws and here is why. Some batteries are in constant use delivering full discharge cycles, others are deployed for infrequent missions, and a third group is mostly on standby. Those in constant use could expire before the appointed time; however, the large majority will last far longer. Premature replacement adds to operational expense and causes environmental concerns. Some batteries with SMBus call for a replacement after delivering a given number of discharge cycles. This is an improvement as it identifies busy batteries from those on standby but the capacity information is Figure 1. Calculating Spare Battery Capacity - Reserve capacity must be calculated for a worst-case scenario. The allowable capacity range is 80 to 100 percent; a spare capacity of 20 percent is recommended for critical use. Cadex Article Continued on Page 12 Winter 2014 * Battery Power 11 http://www.battcon.com http://www.battcon.com http://www.BatteryPowerOnline.com

Table of Contents for the Digital Edition of Battery Power - Winter 2014

Editor’s Choice
IDT Announces Next-Generation WPC 1.1 Wireless Power Receiver for Portable Applications
NREL to Research Battery Storage Approaches in Support of ARPA-E RANGE Program
Features
UPS Goes Green to Save Green
When Rubber Stamping is Not Enough
Purdue University Project Aims to Mass-Produce ‘Nanopetals’ for Sensors, Batteries
Growth in Battery Industry Sparks the Need for Battery Innovation Center
ORNL-Grown Oxygen ‘Sponge’ Presents Path to Better Catalysts, Energy Materials
New Products
Batteries
ICs & Semiconductors
Charging, Testing & Monitoring
ICs & Semiconductors
Components
Manufacturing
Departments
Industry News
Marketplace

Battery Power - Winter 2014