Energy storage is a hot topic, particularly as companies and homeowners look at how best to reduce the use of fossil fuels. One of the most tantalizing forms of energy storage is lithium-ion (Li-ion) batteries, which are often seen as a sort of replacement for the deep-cell, lead-acid batteries that have been used in off-grid PV homes since the 1970s.

Lithium-ion batteries are the types of batteries being used in electric vehicles and hybrids, but a question has lingered, are they safe? A new study by Abt Associates, conducted in partnership with the EPA undertook a lice-cycle analysis (LCA), assessing them on a cradle to grave basis.

Overall the study found that lithium-ion batteries show overall promise to power these vehicles and reduce greenhouse gas emissions, but there’s still room for improvement. “While Li-ion batteries for electric vehicles are definitely a step in the right direction from traditional gasoline-fueled vehicles and nickel metal-hydride automotive batteries, some of the materials and methods used to manufacture them could be improved,” said Jay Smith, Abt senior analyst and co-lead of the life-cycle assessment. 

The report stated that since lithium-ion batteries have a large-energy storage capacity they will continue to be in demand for the automotive industry, where energy storage density counts. “The demand for automotive Li- ion batteries is projected to grow significantly, from about $1 billion in 2010 to $30 billion by 2018,” it said. “Given the importance and projected growth of this technology, the partnership undertook this LCA study to help the Li-ion battery industry identify the materials or processes within a battery‘s life cycle that are likely to pose the greatest impacts to both public health and the environment, and to evaluate nanotechnology innovations in advanced Li-ion batteries for electric vehicles that may enhance battery performance.” It also looked the impact of recycling the batteries at the end of the life-cycle.

The highest potential for environmental and human health impacts are in the nickel and cobalt cathodes and in the solvents used in electrode processing. The potential negative impacts the study found were in “resource depletion, global warming, and ecological toxicity—primarily resulting from the production, processing and use of cobalt and nickel metal compounds, which can cause adverse respiratory, pulmonary and neurological effects in those exposed.”

However, the study also found these negative impacts can be reduced. For instance, the cathode materials can be replaced with other materials electrodes can be produced with solvents. Similarly, the processing and recycling process can be carried out without solvents through a process that actually uses less energy than using solvents.

To make tomorrow’s EV and battery storage systems better, the study made a number of recommendations, including those mentioned above. It also suggested that the percentage of metals by mass can be reduced in Li-ion batteries and associated technologies, like the cooling system, and incorporating recovered materials into the batteries.