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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"Although iron phosphate technology has some challenges, such as in system management due to the fat voltage profle, scientists have developed innovations to overcome them." hydride), and poorer performance at low temperatures. However, the stability traits of the newer solution still prove to be the advantageous ft for maritime operations. Interestingly, iron phosphate's fat voltage profle also offers advantages for designers. The cell provides constant power delivery within a tight voltage window over 80 percent of the state-of-charge (SOC), and storing the battery fully charged has minimal impact on its life. For an application with a narrow voltage window, this utilized energy can be maximized for the most effcient use. However, because battery voltage is not an indicator of SOC or remaining energy as in a metal-oxide-based solution, having a reliable gas gauge for an LiFePO4 battery can be more complicated. Although iron phosphate technology has some challenges, such as in system management due to the fat voltage profle, scientists have developed innovations to overcome them, including innovations to software and electronics to monitor and protect the system effectively over the full operational voltage window, and capitalize on the technology's advantages. Some battery manufacturers have developed advanced iron-phosphate technology that improves the power-to-energy trade-off found in standard iron phosphate. For example, Saft's Super-Phosphate has safety benefts, higher power and higher energy. The battery module and mechanical cell design for cells containing the iron-phosphate chemistry are identical to cells containing Saft's standard lithium-ion chemistry. In this case, Super-Phosphate is interchangeable with traditional lithium ion in system hardware for most applications. Compared with standard lithium-iron phosphate cells, Super-Phosphate technology features safer operation, longer cycle life, better calendar life and a wide operating temperature range. Additionally, the cells have a high resistance to abuse and can safely accept a regenerative charge from foat conditions. Saft designs its cells to withstand common feld abuses, such as overcharge, mechanical shock and vibration, as well as external short circuit, crushing and penetration. Conclusion The implications of hybrid-propulsion pilot projects across maritime applications are far-reaching. As regulations continue to call for further adaptations across the sea, marine operators will realize greater benefts through reduced greenhouse emissions, increased cost savings and extended safety and reliability functions. n Alex Bynum is the business development manager of Saft's lithium battery division in North and South America, which focuses on industrial, commercial and defense applications using a range of primary and secondary chemistries. Bynum's career includes extensive experience in the sales and manufacturing of lithium primary chemistries, as well as complex rechargeable systems. Bynum holds a bachelor's degree in engineering from North Carolina State University. OSIL Salinity Measurement – The complete solution for high quality salinity data • IAPSO Standard Seawater • High precision salinometers • Operator training courses • Salinometer service and repair • Worldwide distribution & support T: +44 (0)2392 488240 / E: / July 2013 / st 13

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