Conformity Magazine - November 2007 - (Page 18)

Safety issues can also arise after overdischarge. The recharge of an overdischarged battery can also lead to an explosion or fire. For overdischarge, the battery under test is overdischarged at its 4 hour rate and at its fastest specified rate for 24 hours. The 4 hour rate version of the test is only performed in Level I. Additional electrical safety testing details are provided here. In Level I: • Level I excessive overcharge, external short circuit, reverse polarity, and overcharge tests simulate typical electrical abuse events that can occur during laboratory evalution when the battery’s full complement of protection is left intact. • Batteries are expected to not explode, ignite, vent, or leak, and to provide some level of performance following excessive overcharge, external short circuit, reverse polarity, and overdischarge abuse. • Electrical abuse is sustained for 24 hours at an ambient temperature of 25°C (77°F). In Level II: • Level II excessive overcharge, external short circuit, reverse polarity, and overdischarge tests simulate typical electrical abuse that can occur during a limited time deployment (e.g., field trial) when the battery’s full complement of protection is left intact. • Batteries are expected to not explode, ignite, vent, or leak during and after abuse. • The abuse is maintained for 24 hours and at an ambient temperature of 75°C (167°F). Following the overcharge, short circuit, voltage reversal, and overdischarge events, the battery’s ability to function safely at 25°C ,when an attempt is made to operate the battery normally, is also evaluated. In Level III: • Level III excessive overcharge, external short circuit, reverse polarity, and overdischarge tests simulates typical electrical abuse that can occur during a full deployment when the battery’s primary protection fails. • Batteries are expected to not explode or ignite, but may vent or leak during and after the abuse. • The abuse is maintained for 24 hours and at an ambient temperature of 75°C (167°F). • Following the overcharge, short circuit, voltage reversal, and overdischarge events, the battery’s ability to function safely at 25°C, when an attempt is made to operate the battery normally, is also evaluated. The following criteria are also included in the electrical safety testing section. Section 4.5.5 - High String Voltage During power plant installation there is a potential for inadvertent series connections of two or more 48 V batteries. This configuration leads to a high-string voltage (80 V to ground) that can cause installer injury and a system fault if the installer inadvertently connects the high string to the DC power plant bus. For conformance, the manufacturer is required to provide documentation stating high string voltage warnings and corrective actions to take when a high string voltage occurs. High String Voltage is a Level I requirement. Section 4.5.6 Electromagnetic Compatability Conducted and Radiated Emissions/Immunity Circuit packs are necessary to protect component cell(s) from misuse and abuse, optimize charge efficiency, gauge reserves, and transmit status and alarms. While in service, circuit packs may: • Radiate energy that affects normal network activity; • Malfunction or fail due to sources of electrical disturbances. Malfunctions or failure can lead to improper management of component cell(s). The conducted and radiated emissions and immunity criteria determine if lithium battery circuit packs can operate safely when subjected to electrical disturbances, and will not radiate energies that can affect the normal operation of surrounding network equipment. Criteria are based on Telcordia GR1089-CORE and encompasses not only the criteria found in FCC Part 15, but also those frequencies above and below the FCC range that are present in a central office environment. Emissions testing is conducted in Level I, and immunity testing is performed in Level II. Batteries are required to operate safely during these tests. Lightning and AC Power Fault Metallic conductors on lithium battery telecommunciations ports, such as wire pairs used for communciating status and alerts, may be exposed to electrical surges resulting from lightning and commercial power system disturbances. Despite the presence of surge protective devices in the telecommunications network that limit the effects of lightning and power surges, a portion of these disturbances can be impressed on the battery’s telecommunications ports. The lightning and ac power fault generic criteria are intended to establish that lithium batteries will fail in a safe manner 18 Conformity noVEmBEr 2007

Table of Contents Feed for the Digital Edition of Conformity Magazine - November 2007

Conformity - November 2007 Contents Editor’s Note Commission Sets Date, Terms for 700 MHz Auction FCC Reaffirms Roaming Obligations Commission Moves to Improve USF Management FCC Proposes Fines for Violations of E911 Handset Requirements Commission Levies $1 Million Plus Fines for Unsolicited Fax Advertisements GR-3150 - Lithium Battery Certification Levels Based on Criteria for General Product, Safety, and Performance, Part 2 ESD Open Forum Machinery Field Evaluation for the United States Validation, Verification, and Immunity Testing Techniques for EMC for Functional Safety Thermal/EMC Simulation Addresses New Mechanical Design Challenges Product Safety Equipment Buyer’s Guide FCC Releases Report on Telephone Numbering Resource Utilization Canada Still Has PCS Spectrum to Assign Updated Standards List for the EU’s Medical Devices Directive Updated Standards List for EU Directive on Active Implantable Medical Devices Call for Papers for the 2008 EOS/ESD Symposium Announced Mobile Phone Use in Hospitals May Be Dangerous CPSC Actions in the News IEC Standards Update UL Standards Update Telcordia Standards Update From Our “You Can’t Make This Stuff Up” Department Product Reviews Looking Back: Items from Past Issues of Conformity Upcoming Events Advertisers

Conformity Magazine - November 2007

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