Lithium Iron Phosphate Lithium Ferrous Phosphate Lithium Ferrophosphate LiFePO, LiFePO4, Li-Iron, LiFe, LFP 4 types of cells (3.2V/cell). Many multi-cell configurations in different form-factors Introduced in 2006 by A123 Systems, which is now bankrupt. Black & Decker was first customer for power tools. Nominal voltage of 3.2V-3.3V/cell. Charging at 3.6V/cell. Charging cut-off power at V Minimum discharge voltage is 2.8V. Maximum charged voltage is 3.6V. *iccnexergy.com. **wikipedia.org

38140S 12Ah lifepo4 battery are the cylindrical EV batteries (38mm x 140mm) 10S2P means 2 parallels with 10 in series each (20 cells total) 20C/30C means maximum constant discharge rate/Burst discharge rate (<10sec) (for LiFePO there is just one C rating) When combining batteries, the participating batteries must all be identical in voltage and capacity. **Lithium-Ion Batteries for Off-Grid Systems. HomePower.com

red Anode (-) on left. Blue Cathode (+) on right. Graphite on copper - terminal on left (anode). Lithium iron phosphate on aluminum + terminal on right (cathode). Iron blue pyramids. Phosphate red triangles. Lithium gray spheres. Main components of a lithium battery are a cathode, anode, separator, electrolyte. Trend for mixed metal oxide cathodes. Lasts longer bz of stability of the LFP cathode and lower charge voltage that slows degradation rate of the anode and electrolyte. - + Discharging : Charging: *J. Molenda & M. Molenda, Composite Cathode Material for Li-Ion Batteries Based on LiFEPO4 System., InTechOpen.com **Lithium-Ion Batteries for Off-Grid Systems. HomePower.com

*BatteryUniversity.com “C” refers to battery capacity and is used to specify charge and discharge rates (0.5C for a 100Ah battery is 50A)

*BatteryUniversity.com Energy Density (Wh/kg) Energy Density

*gnightearth.com Smaller (y-axis). Lighter (x-axis) Energy Density: Size vs. Weight LFP Pb-acid

*GliderPilotShop.com 2.5x avg lifecycle. 2.5x energy density. Much higher cost per unit but not per comparable utility. Maintenance free!

Discharge: 6Amps to 2.4V. Flat voltage drop. Vs. conventional Lithium-Ion battery *iccnexergy.com/articles/1256/iron-phosphate-builds-a-better-battery/ Discharge Test 1

*iccnexergy.com/articles/1256/iron-phosphate-builds-a-better-battery/ LiFePO 12V, 4.6Ah vs 12V, 7Ah Pb-acid. Flat voltage drop across the discharged capacity and for high discharge rates (5A, 10A, 15A, and 20A) Flat voltage drop under 7C continuous and 20C burst Discharge Test 2

LFP cycle life test (12V, 4.6Ah). Longevity due to inherent stability of the LFP cathode & lower charge voltage that slows degradation of anode & electrolyte. *iccnexergy.com/articles/1256/iron-phosphate-builds-a-better-battery/ Cycle Life Test

*gwl-power.tumbler.com/post/ /depth-of-discharge-dod-all-battery Depth of Discharge DoD State of Charge (SoC), Depth of Discharge (DoD). 80% or less DoD is always recommended. 50% DoD LiFePOs may have well above 5000 cycles. Lower DoDs = longer cycle life Central capacity range = longer cycle life. Central part of capacity range (green zone).

* Discharge Curve1 Capacities ranging from 40Ah to 7000Ah. Operational voltage 2.5V - 3.6V. 3.2 V Expected Cycle Life with Respect to DOD (0.5C Dec C)

* Discharge Curve2 3.2 V Discharge Curve Under Different Temperature Conditions Stable between 25 and 55C

* Depth of Discharge DoD State of Charge (SoC), Depth of Discharge (DoD). 80% or less DoD is always recommended. 50% DoD LiFePOs may have well above 5000 cycles. Lower DoDs = longer cycle life Central capacity range = longer cycle life. Central part of capacity range (green zone).

* Self Discharge 3.2 V Cell Self Discharge (25°)

Lower energy density Still expensive Cell imbalance during charging Thermal runaways Catastrophic field-failures Lithium-intensive Fast/powerful Rugged/durable Stable/reversible Long-lived Safer Cost-effective Low voltage drop under load Predictable end of life Thermally stable to 300 o C Non-explosive No oxygen emission +‒ *BatteryUniversity.com. ** ***batteryspace.com ****cobox-ebikes.com. *****GliderPilotShop.com high charge/discharge rate. Excellent cycle life (life of 5-7 yrs). Abundant P & Fe resources. high power applications like EV, power tools). 4-5x life of a traditional lithium cell: no calendar-based schedule replacement. Does not emit oxygen when over charged as do Ni, Co, and Mn based oxides (precursor to thermal runaway in a conventional lithium battery). long cycle life Balancing issue: needs management boards that control each cell

1,000,000 duty cycles 10yrs DC life, 4yrs shelf Shock/Vibration resistance -40 o C to 65 o C operation Low charge/discharge temp ∆ 4Wh (14kJ), 7.5Wh /kg (energy) 8.0kW /kg (power) 18mA /72hrs (leakage) 0.22 mOhms (ESR) 100A cont, 2,000A peak, 10,000A sc, 3V max Electric double-layer capacitors (EDLC): supercapacitors (ultracapacitors). High power/energy, fast charge/discharge, low temperature operation. not for AC. The future of batteries…may not be batteries at all. 3500F typical capacitance (3400 min). AAA NiMH (HR03, 1.2V/0.8Ah): 3.5kJ or 1Wh (70Wh/kg; ). AA NiMH (HR6, 1.2V/2.4Ah): 10kJ or 3Wh (97Wh/kg; ). Discharge current at milliamps (1A max). 2.7V: 1.8kJ or 0.5Wh. 2.7V: 7.3kJ or 2Wh Maxwell BCAP F, 2.85V ($55-$71) *maxwell.com, allaboutbatteries.com

*wikipedia.org Note Supercapacitors!!! Energy vs. Power Density