Battery technology is evolving from Nickel Metal Hydride and Nickel Cadmium to a variety of Lithium-Ion battery chemistries. One of the most promising lithium-ion-derived chemistries is the Lithium Iron Phosphate battery (LiFePO₄).

The two categories of lighting that most employ batteries are emergency lighting and solar lighting. Both of these categories are gradually transitioning to LiFePO₄ batteries. Advantages of LiFePO₄ include:

• Mineral availability – Iron and phosphate are commonly available, while nickel and cobalt have limited availability and high cost.
• Cost – A 2020 US DOE analysis found that LiFePO₄ was 6% lower cost than Lithium Nickel Manganese Cobalt Oxide batteries (NMC). Legacy nickel-based batteries currently have lower initial costs; however, savings can be achieved through lower energy consumption, better longevity, and reduced maintenance costs – which can all be achieved by switching to Lithium Iron alternatives. Lastly, nickel pricing is spiking and will likely continue to go up.
• Cadmium free – Cadmium is a toxic heavy metal in NiCad batteries. LiFePO₄ doesn’t contain Cadmium nor other heavy metals.
• Environmental tradeoffs – Lithium, cobalt, and nickel production all create environmental concerns, which is a problem for all of the battery formulations. However, LiFePO₄ can be recycled to recover the materials used in the electrodes, wiring, and casings, making them the lowest impact on the environment.
• Battery life — LiFePO₄ will typically have 3,000+ charging cycles, to as many as 10,000 cycles in ideal situations. NMC batteries typically have 1,000 to 2,300 charging cycles. LiFePO₄ have greater calendar-life (slower capacity loss) than cobalt or manganese lithium-ion polymer batteries or other lithium-ion batteries.
• Safety — LiFePO₄ have greater thermal and chemical stability which improves battery safety. LiFePO₄cells are harder to ignite in the event of mishandling (especially during charging). The LiFePO₄ battery also does not decompose at high temperatures.

Long-term, it is hoped that Sodium-ion batteries will replace Lithium-ion chemistries, but that is likely years away from commercial viability.

Top Image: Soltech’s SUNLIKE solar area light with LiFePO₄ batteries

Image: Tridonic LiFePO4 Accus 1.5 – 9.0 Ah emergency lighting battery

David Shiller

David Shiller is the Publisher of LightNOW, and President of Lighting Solution Development, a North American consulting firm providing business development services to advanced lighting manufacturers. The ALA awarded David the Pillar of the Industry Award. David has co-chaired ALA’s Engineering Committee since 2010. David established MaxLite’s OEM component sales into a multi-million dollar division. He invented GU24 lamps while leading ENERGY STAR lighting programs for the US EPA. David has been published in leading lighting publications, including LD+A, enLIGHTenment Magazine, LEDs Magazine, and more.

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