Sea Technology

JUL 2013

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

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ity gauging. In addition, the modules completed pressure verifcation tests of multiple cycles to 6,000-meter depth capability (10,000 pounds per square inch) at an independent mechanical engineering frm in Texas. Maximum stateof-charge is confgurable and is managed by the BMS to optimize extended operating life up to 15 years. Charge is provided by off-the-shelf constant-voltage/constantcurrent power supplies. The module enclosure is fberglass flled with thermally conductive, fameretardant polyurethane potting material. In addition to its thermal benefts, the potting material also dampens shock and vibration. The modules are UN DOT 38.3 certifed for transportation. They can be confgured in customerdesigned cases or within an SWE-supplied SeaSafe battery case. thus increasing reliability. For instance, if one string of two series-connected modules is accidently shorted, both modules monitor the shorting current, with two opportunities for the short to be autonomously interrupted. The SeaSafe PII can be used when the battery system has parallel strings of modules or cases. The PII is a diode O-ring circuit and enables increase in battery system amp-hour capacity with redundancy. If one string should fail, other parallel strings would continue to function normally. The PII also allows faster charging of multiple strings and isolates multiple strings during discharge, thereby preventing potential high-current discharge from one parallel string to another. One PII is used with each module string connected in parallel. PIIs are not needed for singlestring confgurations. Safety, Reliability Features The SeaSafe Battery SeaSafe Battery Systems System has safety and reliSWE SeaSafe Battery Sysability features that assure tems are built with SeaSafe safe operation, protect the Battery Modules installed in module's cells from daman SWE-designed pressureage and prolong cell life. equalized case. Up to four Autonomous safety and SeaSafe Modules can be conreliability features include fgured within one case in a three types of intra- and Observer software for SeaSafe Modules. series/parallel combination of intermodule balancing to modules to meet voltage and amp-hour capacity needs, deassure cell safety and reliability, algorithms to detect internal livering up to 132 volts or 112 amp-hours maximum. Multicell shorts to notify and/or prevent failures from lithium denple cases can be stacked and connected to increase voltage drites, algorithms to prevent formation of metal dendrites and/or amp-hour capacity. The system is pressure tolerant subsequent to copper dissolution, confgurable control of down to 6,000 meters. The pressure-equalized case is built charge level within each battery module to extend battery rugged from 316 stainless steel and incorporates SEA CON cycle life and safety, thermal control of cells and modules to (El Cajon, California) WET-CON connectors. assure battery safety and extend operating life, short circuit The case has a translucent urethane bladder that equalizfuse protection for safety redundancy should system eleces ocean-depth pressure with the battery modules immersed tronics fail, and classic lithium-ion safety features confguwithin the case in pressure-compensation oil. The dimenrable to specifc applications and missions. sions of the case are 14.8 by 15.6 by 17.8 inches. There are custom thresholds for over- and under-voltWhen SeaSafe Battery Modules are connected in a seage detection and prevention, excessive charge and disries string, many autonomous safety features are redundant, charge current detection and prevention, ensuring charge 22 st / July 2013

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