Conformity Magazine - November 2007 - (Page 20)

Section 5.1.6 Extended Outages Extended outages are times when commercial power cannot be restored quickly due to bad weather or a natural disaster, and the facility for network communication is not in service. These outages can last a few days to a week until network personnel can visit the location and correct any commercial and/or network powerpath problems (i.e., broken load power lines). During these times, it is critical for batteries with electronic management to retain their charge while AC and network power problems are being corrected. The charge retention capabilities of the battery are dependent on the activity of its electronic management system. Electronic batteries maintain various modes of operation. The operations of these electronics drain cell energy as soon as the battery is turned on. Active electronics can force a battery to shut down permanently or reverse. When in service, the circuitry that controls the electrochemistry is constantly operating and becomes a parasitic drain to the electrochemistry when the battery is in open circuit or when the battery is in discharge. The electronics are needed to optimize safety and efficiency; however, care should be taken to ensure that the battery management consumes minimal energy from the battery. When network power paths are restored, it is important that the batteries provide a certain level of performance to ensure resumption of network operations. Batteries that fail to do this will place an additional strain on network personnel. For the Level III extended outages test, batteries with management systems are required to function for a minimum of 7 days at an ambient temperature of 35C (95 F) after being discharged to 42 V. Following the 1 week period, the batteries are recharged and are required to provide a certain level of performance when discharged to 42 V. An objective for two weeks of battery functionality during an extended outage is also detailed in the GR. 20 Conformity noVEmBEr 2007 Battery crushing is considered extreme and rare. For compliance, battery explosion and ignition is disallowed; however, battery venting or leaking is anticipated and permitted. When tested, batteries are unpackaged and charged to the manufacturer’s normal shipping SoC and slowly crushed between two flat non-conductive surfaces by a force of 9000 lbs (4,082 kgs). The battery is crushed in its longitudinal and traverse orientations. Crush test test setups are shown in Figure 5. Section 4.6.3.3. Low-Level Vibration Resistance Batteries may be subjected to low-level vibration in service caused by nearby rotating equipment, adjacent rail or truck traffic, or construction work in nearby spaces or buildings. This vibration can cause circuit board “walkout,” malfunctions, or other service interruptions or failures. For testing, a fully assembled and charged battery’s resistance to a low-level vibration profile which simulates nearby rotating equipment, adjacent rail or truck traffic, or construction work in nearby spaces or buildings is evaluated. Batteries are required to sustain normal operation, without manual rebooting or replacement of components, during the exposure. Testing is performed according to the requirements detailed in the latest issue of GR-3108-CORE, Generic Requirememts for Network Equipment in the Outside Plant (OSP). Low-level vibration resistance is a Level III test. Other Sections of GR-1350 Also included in GR-3150 are Sections 5 and 6, which detail lithium battery performance and service life requirements, respectively, and appendices providing a list of referenced documents (Appendix A), a list of acronyms used in this GR (Appendix B), and a glossary (Appendix C). Section descriptions are provided here. Requirements in Section 5, Performance Criteria, address lithium battery electrical and environmental performance. Float voltage and capacity (Section 5.1.1), recharge time (Section 5.1.2), end of discharge (eod) voltage (Section 5.1.3), cycling (5.1.4), shelf-life and charge retention (5.1.5), extended outages (5.1.6) requirements are defined in Section 5.1, Electrical Criteria. For Section 5.2, Environmental Criteria, requirements addressing temperature and humidity shock during transportation and storage, cold temperature start, salt fog exposure, particulate containment and resistance to corrosive gases performance are provided. Section 6, Service Life Criteria, provides service life guidelines and rationale for Arrhenius-based accelerated life testing. This is an introduction to a possible method for determining service life by accelerated testing. Criteria for determining service life is not provided in the GR because: 1) the technology is new thus insufficient experience exists to predict all possible battery failure modes; and 2) the broad

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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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