Abstract
The effects of variable charging rates and incomplete charging in off-grid renewable energy applications are studied by comparing battery degradation rates and mechanisms in lead-acid, LCO (lithium cobalt oxide), LCO-NMC (LCO-lithium nickel manganese cobalt oxide composite), and LFP (lithium iron phosphate) cells charged with wind-based charging protocols. Poor pulse charge acceptance, particularly for long pulses, contributes to incomplete charging and rapid degradation of lead-acid cells due to apparent high rates of sulphation and resistance growth. Partial charging and pulse charging, common lead-acid stressors in off-grid applications, are found to have little if any effect on degradation in the lithium-based cells when compared to constant current charging. These cells all last much longer than the lead-acid cells; the LFP batteries show the greatest longevity, with minimal capacity fade observed after over 1000 cycles. Pulse charge acceptance is found to depend on pulse length in lead-acid and LFP cells, but not in LCO and LCO-NMC cells. Excellent power performance and consistent voltage and power behavior during cycling suggest that LFP batteries are well-suited to withstand the stresses associated with off-grid renewable energy storage and have the potential to reduce system lifetime costs.
Original language | English (US) |
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Pages (from-to) | 492-500 |
Number of pages | 9 |
Journal | Energy |
Volume | 60 |
DOIs | |
State | Published - Oct 1 2013 |
All Science Journal Classification (ASJC) codes
- Civil and Structural Engineering
- Modeling and Simulation
- Renewable Energy, Sustainability and the Environment
- Building and Construction
- Fuel Technology
- Energy Engineering and Power Technology
- Pollution
- Mechanical Engineering
- General Energy
- Management, Monitoring, Policy and Law
- Industrial and Manufacturing Engineering
- Electrical and Electronic Engineering
Keywords
- Capacity fade
- Lead-acid
- Lithium-ion
- Off-grid renewables
- Variable charge
- Wind