Snohomish County Public Utility District No. 1

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PUD Battery Technologies

Lithium Ion Batteries

Lithium ion covers a broad array of chemistries, all which transfer lithium ion between the electrodes during charging and discharging. The Energy Storage Association states that “li-ion cells do not contain metallic lithium; rather, the ions are inserted in to the structure of other materials, such as lithiated metal oxides or phosphates in the positive electrode (cathode) and carbon (typically graphite) or lithium titanate in the negative (anode).” Li-ion batteries have been used for many applications, including in electric vehicles, rooftop solar units and utility scale multi-megawatt projects.

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Vanadium Redox Flow Batteries

These batteries store energy through vanadium redox couples. According the Energy Storage Association “these active chemical species are fully dissolved at all times in sulfuric acid electrolyte solutions.” The first such batteries were first demonstrated at the University of New South Wales in the late 1980s.

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