Battery Technologies

Brad BassettSr. Application Engineer

Battery TypesUsed for solar

• Deep-Cycle Flooded LAo Lead-Acid battery with liquid sulfuric acid electrolyteo Grid alloy with Antimony for deep cycle capability

• Deep-cycle VRLA (Valve Regulated Lead Acid) (AGM or Gel)o Lead-Acid battery with Absorbed Glass Mat (AGM) or gelled sulfuric acid electrolyteo Thin Plate Pure Lead (TPPL), or grid alloy with Calcium/Tin for deep cycle capability and

reduced gassing• Carbon LA

o Lead-Acid battery flooded or VRLAo Carbon or nano-carbon added to the negative plate

• Tubular plate LAo Lead-Acid battery flooded or VRLAo Internal construction with plates in tubular like form

• Lithium-Ion (NMC) o Lithium-Ion with Nickel–Manganese–Cobalt electrode

• Lithium Iron Phosphateo Lithium with Iron-Phosphate electrode

• Nickel-Irono Nickel Iron (Edison cell) battery with alkaline flooded electrolyteo Nickel Cadmium and NiMH

• Othero Lithium Titanate, other lithium chemistries etc.

Appropriate uses for Battery Types

• Off-Grid, Residential or Industrialo Deep-Cycle Flooded LA, Deep-cycle VRLA (Valve Regulated Lead Acid) (AGM or Gel),

Carbon LA, Tubular Gel, Lithium Iron Phosphate, Nickel types

• Grid-Tie Backup Powero Backup VRLA, Lithium-Ion (NMC), Lithium Iron Phosphate, Carbon LA, Tubular VRLA

• Self-Consumption (Self-Supply) and Time of Useo Lithium-Ion (NMC), Lithium Iron Phosphate, Carbon LA

• Peak-Load Shavingo Lithium-Ion (NMC), Lithium Iron Phosphate, Carbon LA, Deep-cycle VRLA, Tubular VRLA

Flooded Lead Acid (Deep Cycle Type)

• Lower initial cost than VRLA in smaller sizes

• Moderate to Excellent cycle life

• Electrolyte loss is replaceable

• Less sensitive to overcharging

• Not sealedo Cannot be mounted on its sideo Ships as hazardous goodso Cannot be shipped by airo Requires isolation (seal ducts) &

ventilationo May require spill containment and

absorption equipment

• Maintenance requiredo Water must be added ~monthlyo Regular equalization charges neededo Reduced life at higher temperatures

• Less efficiento Higher self discharge, o Higher float current than VRLA batteries

Pros Cons

HuP Solar One Flooded Lead-Acid

Valve Regulated Lead Acid – VRLA (AGM or Gel)

• Low maintenance o No watering needed

• Sealedo Can be installed on its sideo Can be shipped as non-hazardous

(generally)o Can be shipped by air

• Low to Excellent cycle life

• High efficiencyLow self discharge and float current

• Thin Plate Pure Lead (TPPL) can have very high charge current

• Somewhat shock and vibration resistant

• Damaged by severe overcharging, electrolyte cannot be replaced

• Reduced life at higher temperatures

• Higher cost than Flooded LA in smaller sizes, similar in larger sizes

Pros Cons

Deka Unigy II (AGM)

OutBack EnergyCell

Valve Regulated Lead Acid – Larger types

Tubular Plate Gel

Carbon EnhancedLead-Acid

• Carbon or nano-carbon is added to the negative plate of lead acid batteries, either sealed or flooded, to improve partial state of charge performance

• Extended partial state of charge (PSoC)o Sulfation on the negative plate is minimizedo Much less need for regular full chargeo Good for self-consumption or off-grid o Higher charge rate acceptance

• Longer cycle life in real conditionso Can be cycled in mid state of chargeo Up to 44% improvement in cycle lifeo Increased round trip efficiency (VRLA)o Only about 15% higher price

• Available in AGM or Floodedo OutBack Energy Cell Nano-Carbon AGMo Trojan SmartCarbon flooded

Tubular plateLead-Acid

• Tubular plate construction lead acid batteries, either sealed or flooded, to improve deep cycle performance

• Very robust for long deep cycle lifeo Up to 3000 cycles at 50% depth of dischargeo High charge rate acceptance

• Meets European DIN standard for cyclingo OPzV for VRLA gel typeo OPzS for flooded type

• Available in OPzV gel o OutBack Energy Cell OPzV, shipping from Greece.

comes with rack and cableso Discover OPzV, shipping from N. America, comes

with rack and cables

LG Chem HV Lithium-IonLithium Nickel-Manganese-Cobalt (NMC)

• NMC chemistry is widely used in EVs • Works at higher DC voltage with lower

cost inverters• Very high energy density and efficiency

o Lighter and smaller packageo Up to ~45 Wh/lbo High round trip efficiency up to 92.5%

• Partial state of charge operationo Preferred use at partial state of charge

• 10 year life at high cycle deptho Over 3,000 cycles @ 80 to 90% DoD

• Expensiveo More expensive than lead-acid batterieso Unknown calendar life >=10 yearso Limited number of units in parallelo Not approved for off grid use

• Thermal management challengeso Operates between 14°F and 113°F, preferred

between 59°F and 86°Fo Not approved for installation at sites over 6,562

feet (2000m) elevation

• Requires sophisticated battery management system (BMS)o DC-DC converter in battery to get higher voltageo Only works with specific inverters with

compatible communications

• Recyclable? and hazardouso Disposal costs not typically included in priceo Ships as hazardous goods, shipping restrictionso Will possibly support combustion in a fire

Pros Cons

Discover AESLithium Iron Phosphate LFP (LiFePO4)

• High energy density and efficiencyo Lighter and smaller packageo Up to ~35 Wh/lbo High charge efficiency up to 95%o Reduces generator run time substantially

• Partial state of charge operationo Preferred use at partial state of charge

• Long life at high cycle deptho Over 4200 cycles @ 90% DoD and countingo Warranted throughput of 16 MWh (48 Volt

unit)

• Easy to installo Works with most 48 volt nominal inverterso LYNK multi-function gateway with daughter

boards for communication with various inverters

o Integrated communications to Schneider Xanbus system networks

o Up to 20 units paralleled for larger capacity (132 kWh)

• Expensiveo More expensive than top line lead-acid

batteries or Li-ION, but is expected to have much longer life in most applications

• Thermal management challengeso Operates between 32°F and 113°F,

preferred between 59°F and 77°F

• Recyclable? and hazardouso Disposal costs not typically included in

priceo Ships as hazardous goods, shipping

restrictions

Pros Cons

Nickel Based BatteriesNiCd, NiFe, NiMH

• Fair to good energy density o NiCd about 60% of Lithium-iono NiFe much lower energy density

• High cycle life at high cycle deptho Up to 5,000 cycles or more @ 80% DoD

for flooded NiFe and NiCd

• Robust (Flooded cells only)o No sudden failures, no memoryo Tolerant of under and overchargingo Very wide operating temperature range

• Very Expensiveo 4 - 5 X price of lead-acid batterieso Heavy metals, Nickel and/or Cadmiumo NiMH small sealed cells only

• Low cell voltage o Low cell voltage (~1.2 VDC)o More cells required per system

• High self-discharge rateo NiFe has very high self discharge

• Alkaline electrolyteo NiFe has very high maintenance o Requires electrolyte changes every 10 years

Pros Cons

NiFe Battery bank

Battery Technologies

Questions?