As more energy storage systems are required to solve the intermittency of renewable energies and as more electric cars hit the road, the higher the volume of manufactured batteries, specially of lithium-ion batteries. Over the past decade, the world’s lithium-ion production capacity has increased nearly tenfold to meet the growing demand (from a production base of 19GWh in 2010 to a production of 160GWh in 2019).

Figure 1. Annual Li-ion Battery demand

As of December 2019, the number of lithium-ion battery megafactories in the pipeline has reached 115 plants. The main manufacturers being LG, CATL, BYD, Panasonic and Tesla.

Figure 2. Top 5 Li-ion manufacturers by capacity (GWh)

Batteries from the first production wave are reaching today their end-of-lifetime and there are already debates on what to do with this hazardous waste. Considering Li-ion batteries production is increasing exponentially, this first wave is just the beginning of a raising concern - battery waste time bomb is the downside of the EV and renewables revolution.

Figure 3. Volume projection of Li-ion batteries.

Recycling process

Many battery technologies are easily recyclable, lead batteries recycling for example typically exceed 95% recovery with no loss of performance. The recovered materials are used in a variety of applications, including new batteries - more than 60% of lead production originates from end-of-life products.

Lithium batteries are recyclable but is not that simple. There are two main ways to deactivate lithium-ion batteries. The most common technique, called pyrometallurgy, involves burning them to remove unwanted organic materials and plastics. This method leaves the recycler with just a fraction of the original material—typically just the copper from current collectors and nickel or cobalt from the cathode. A common pyro method, called smelting, uses a furnace powered with fossil fuels, which isn’t great for the environment, and it loses a lot of aluminum and lithium in the process but is still used for its simplicity.

The other approach is called hydrometallurgy. A common form of this technique, called leaching, involves soaking lithium-ion cells in strong acids to dissolve the metals into a solution. More materials, including lithium, can be recovered this way. But leaching comes with its own challenges. Recyclers must preprocess the cells to remove unwanted plastic casings and drain the charge on the battery, which increases cost and complexity.

Specific dangers associated with lithium-ion battery complex and expensive recycling processes are: electrical dangers, chemical dangers, burning reactions, and their potential interactions. Being so, less than 5% of spent lithium-ion batteries are recycled today and in most cases lithium is not even extracted as the extraction of lithium from old batteries is five times more expensive than mined lithium. However, Li-ion batteries recycling is already being done on a small scale.

Companies at play & further innovation

Redwood is part of a wave of new startups racing to solve the problem. Redwood uses a combination of pyrometallurgy and hydrometallurgy to recover these valuable materials. Redwood’s CEO and founder J. B. Straubel (former CTO at Tesla) claims that it can recover between 95% and 98% of a battery’s nickel, cobalt, copper, aluminum, and graphite, and more than 80% of its lithium.

Later this year, the Canadian firm Li-Cycle will begin constructing a US $175 million plant in Rochester, N.Y. When completed, it will be the largest lithium-ion battery-recycling plant in North America. Li-Cycle takes a different approach to recovery than Redwood. The company’s process skips smelting entirely and refines the battery with leaching alone. “We don’t produce any meaningful amounts of waste” says Tim Johnston Li-cycle’s Co-founder. “We don't produce any meaningful amount of air emissions, we don't produce any waste water, and everything is done at a low temperature. The footprint is very small.”

Fortum achieves a high recycling rate of 80% with a low carbon footprint also using hydrometallurgical recycling process. The lithium-ion batteries are first made safe for mechanical treatment, with plastics, aluminum and copper separated and directed to their own recycling processes. Then the ‘black mass’ is treated on an industrial scale.

Smelting and leaching are the quickest ways to address the rapidly growing challenges with lithium-ion waste, but they may not be the best ones. Some companies are working on a process called direct recovery or direct recycling, which salvages cathode material without destroying its crystalline nanostructure. This reduces the cost of reusing the material. The challenge with direct recycling is that cells are not designed with material recovery in mind. Besides, there is a whole range of different li-ion batteries and is difficult to know which chemistry you may have to recycle if these are not labeled. Being so, it is difficult to practice direct recycling on a commercial scale.

Figure 4. Other Lithium-Ion Battery Recycling Facilities Worldwide classified according to their primary recycling method.

Aceleron’s solution to the problem is simple. The company’s battery platform, Circa, compresses the batteries in a hard shell case and uses a removable circuit to connect them. This means that if an individual cell fails, or the pack’s owner wants to upgrade to a better battery, the cells can be swapped out. “We had to reinvent how you assemble batteries with something that is designed for reuse as well as recycling” Carlton Cummins, the CTO of Aceleron stated.

The lithium-ion battery recycling industry is in its infancy, and still has a lot to prove it can be done economically. But, with current high pricing for cobalt and lithium, and a huge demand wave for Li-ion batteries on the way, the Li-ion recycling industry may soon emerge as a new trend.

References

Daniel Oberhaus. The Race To Crack Battery Recycling-Before It’s Too Late [Online]. Wired. Published: 11/30/2020. Accessed: 10/03/2021. Link.