Cornell researchers and a Binghamton battery company reduced a costly step in lithium-ion battery manufacturing by up to about 60% in facility tests while maintaining performance comparable to the company’s conventional process.
The team developed two faster manufacturing protocols after watching protective layers form inside working batteries, according to a Cornell account of the research. The collaboration with Charge CCCV, known as C4V, focused on battery formation, the initial charging and discharging cycles that help determine a battery’s lifetime performance.
Formation creates protective layers at interfaces inside a new battery. Cornell said the process accounts for roughly one-third of production costs and a quarter of a factory’s floor space, making it an expensive part of cell manufacturing.
The findings were published Oct. 28 in the journal Energy Storage Materials. Graduate student Jantakan Nedsaengtip was the lead author, and Vibha Kalra, a chemical engineering professor in Cornell’s Duffield College of Engineering, was the principal investigator.
Watching protective layers develop
Manufacturers typically evaluate formation processes through trial and error, Kalra said. Assessing long-term performance can take months or years because batteries must run through thousands of cycles.
Her laboratory has spent more than a decade developing ways to observe batteries as they operate. For this project, the researchers combined two techniques: operando Raman spectroscopy and operando electrochemical impedance spectroscopy.
Together, the methods let the team track the chemistry of the protective interfaces and changes in their electrical resistance during formation. That provided a real-time view of how the layers developed, rather than relying only on later performance tests.
The researchers found that slower charging helped create a stable interface with more uniform protective layers rich in inorganic material. They also found evidence that faster discharging could shorten the overall formation process. Key resistance measurements stabilized after 1.5 cycles.
Those observations informed the two accelerated protocols tested at C4V’s facility. Both shortened formation time while producing battery performance comparable to the company’s existing process, according to Cornell.
Potential savings for larger factories
A shorter formation process could free manufacturing space and reduce inventory tied up in production. Shalabh Gupta, C4V’s system engineering manager, said combining laboratory measurements with the constraints of large-scale manufacturing helped translate the research into a usable manufacturing approach.
Formation accounts for roughly one-quarter of a battery plant’s electricity consumption, according to Gupta. The team estimated that cutting formation time by half or more could reduce a manufacturer’s overall power use by 10% to 15%.
For a factory consuming more than 10 gigawatt-hours annually, Cornell reported the team’s estimate of up to $100 million in annual formation-cost savings. Those power and cost figures are projections; the reported C4V tests established shorter formation time and comparable battery performance.
The partnership developed through the National Science Foundation’s Energy Storage Engine in Upstate New York, based at Binghamton University. Cornell is a core technology-translation partner, and C4V supplied the battery materials for study at its Binghamton operations.
Kalra also directs the Cornell Atkinson Center for Sustainability. Stan Whittingham, the NSF engine’s chief innovation officer and a 2019 Nobel laureate for his work on lithium-ion batteries, said academic-industry projects can help research reach manufacturing sooner by bringing the needed teams together.
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