The use of dry electrode manufacturing in the production of lithium ion batteries is beginning to scale, promising to significantly lower emissions and further reduce costs in the future.
Tesla is set to start producing some of its battery cells using the dry process at the end of this year, while battery producer LG Energy Solution said this week it is developing dry electrode manufacturing to “achieve higher energy density and cost innovation.” The company aims to build a pilot production line in Korea by the end of this year.
And Massachusetts-based startup AM Batteries, which is backed by Toyota Ventures and Porsche Ventures, said this month it had shipped samples from its pilot line to “a major battery cell provider.”
Dry processing cuts down the number of steps needed to produce battery electrodes, as well as removing the need for the use of a solvent to make a slurry.
In most battery factories today, cathode and anode materials are mixed with polymer binder and conductive additives in wet solvent to create a slurry, which is coated onto aluminum or copper foils. These are then heated to around 100 degrees centigrade in an oven.
In the dry processing method cathode or anode material powders are sprayed directly onto the metal foils that make up the electrode.
Because the dry process cuts out the need for ovens to heat the electrodes, it can offer significant energy savings. It also removes the use of NMP solvent, which can be toxic to humans and also be harmful to the environment.
Tesla said last month that it had produced its 100-millionth 4680 battery cell and “continued to progress our dry-cathode manufacturing lines.”
Lie Shi, the chief executive of AM Batteries, told Benchmark Source that the process could reduce energy consumption by around 40%.
AM Batteries has built a first engineering pilot line, which allows the company to make electrode films continuously at “reasonable speed,” Shi said. It aims for full production in 2026, he said.
“So in three years, we’re trying to scale up quickly to the production level,” he said. The company wants to sell its dry coating equipment as well the know-how to other battery manufacturers.
LG Energy Solution says it’s aiming to start mass production of dry electrode technology by 2028.
Check out the exclusive video interview with our CEO, Lie Shi here.
Competing with China
Reno, Nevada-based DragonFly Energy said the dry electrode process means battery production will be a little cheaper than Chinese lithium ion battery production today.
“And that’s before you take into account tariffs, the IRA, and tax credits,” Tyler Bourns, chief marketing officer at DragonFly said. “We need an innovation like this in order to compete with China.”
The company uses spray drying to prepare electrode feedstock materials before the powder is coated onto the metal foil. Its process pre-coats the materials in polymer binders and conductive carbons.
“We’re able to effectively coat the particles in a really homogeneous uniform way,” Emily Litt, director of R&D at Dragonfly Energy, told Benchmark Source. “We almost saran wrap the polymer binder around each individual particle grain and without that step the powder coating isn’t nearly as effective.”
Overall it says its process reduces energy usage by around 25% compared to conventional battery production and the carbon footprint of the entire battery cell by around 9%.
Stricter Controls on NMP Solvents
N-Methylpyrrolidone (NMP) solvent, which is currently used to produce lithium ion batteries, is considered to have damaging impacts on reproductive health and is classed by the European Chemicals Agency as a “substance of very high concern.”
The US Environmental Protection Agency says that it “causes serious health effects, including miscarriages and reduced fertility, as well as damage to the liver, kidneys, immune system and nervous system.”
In June, the EPA proposed stricter controls on the use of NMP solvent, including safeguards for employees working with the substance. This could limit the manufacturing of lithium ion batteries, according to the US Chamber of Commerce.
This summer protests in Hungary against a battery factory there said the solvent was found in the water.
Companies wanting to build even small battery production facilities have had trouble with permits due to this chemical, AM Batteries’ Lie said.
“Using this dry process, AM batteries should be able to provide a solution which not only saves energy but also allows the environmental concern to be addressed,” he said.
The solvent has a really high boiling point, around 200 degrees centigrade, which means that a lot of energy is required to evaporate it off during the battery manufacturing process, Litt said. Because it’s toxic, it also needs to be recovered after use.
“There’s a lot of precaution and safety steps that have to be implemented because it is this toxic solvent,” she said.
