Used lithium ion batteries can serve as energy storage for lighting in remote rural areas of developing countries
Nowadays, people discard their cellphones every three years on average. However, their lithium ion batteries have a lifetime of about five years. Researchers at Kyung Hee University in Seoul, Korea spotted this discrepancy and in an effort to reduce the e-waste, proposed a model for reusing unspent lithium ion batteries into solar power systems. The batteries are used as energy storage units for solar-powered LED lamps. Their proposal would provide both energy and economic growth for rural communities, where candles or kerosene lamps are still the main source of lighting.
Their research was published in the Journal of Renewable and Sustainable Energy, and the proposed program consists of five general steps - battery collection, testing and selection, system manufacturing, commercialization, and installation. Batteries are one of the more expensive components of a solar home system and contribute significantly to the cost barrier of decent lighting systems in rural communities.
The promising prototype
A standard Li-ion phone battery of 1000 mAh capacity can power a 1W LED lamp for about 3 hours, or a 0.5W lamp (bright enough for reading and writing) for about 6 hours. The prototype is a full 12V system made of three mobile phone batteries of 3100 mAh capacity each, with a 5W LED lamp and a small solar panel, and costs less than $25. A system like this can light up a room for about 5 hours each day, and can last for approximately three years without any maintenance before the battery needs to be replaced.
The research team plans to start pilot projects in Senegal and sub-Saharan African countries within the next year.
The prototype system consisting of a solar panel and 12V LED lamp wired to a battery pack containing three Samsung Galaxy Note 2 batteries.