Battery Manufacturing Needs More Attention

In the realm of EV batteries, much of the discussion seems to revolve around materials and chemistry. Researchers around the world are trying to find the magic recipe that will yield more energy density and power from raw materials that are cheaper and more accessible. But designing a better mousetrap is only as useful as your ability to produce it. Manufacturing is rarely the sexy, attention-grabbing part of the process, but it is among the most important. Before the next technology leap is achieved, such as solid state cells, the next major breakthrough may actually be in electrode coating, and a small Michigan startup thinks it has the answer. 

A cell consists of the negative anode and the positive cathode foils coated with active materials such as nickel manganese cobalt, a separator film to keep them from shorting and a conductive electrolyte, all stuffed into a package. One of the most difficult parts of production is coating active materials onto the foils.

Today, most coating is produced by roughly the same “wet” process whereby a slurry of the active powder mix is applied to the foil and then run through rollers to get an even coating before drying it and rolling it up. The drying process consumes large amounts of energy and floor space in factories. 

At its September 2022 battery day, Tesla announced a new dry coating process that it was developing for electrode production. That process involved applying a dry metal powder mixture directly to the aluminum foil and pressing it down with rollers. Through elimination of drying and solvent recovery, it was claimed that this process would reduce the $/kWh cost of cells by 18%. However, 2 years later, the company is still struggling to scale this process due to low yields and mechanical issues. 

At the recent Battery Show North America in Novi, Michigan, a local startup called Intecells displayed a completely different dry coating process that shows real promise for achieving the goals of lower cost and improved performance. Intecells Is using a cold plasma process to treat the surface of the foil for improved adhesion and then applying the active material mix. The nature of the process allows the creation of a thicker coating with a structure that helps to improve energy density. 

In essence, this approach is a form of additive manufacturing, building layers of the cell. It is agnostic to the cell chemistry and can even be integrated with current slurry wet processing. However, the real benefits come from dry processing. Samples produced by Intecells include the application of cathode material, solid electrolyte, and anode. By eliminating the polymer separator and binders, internal resistance is reduced and performance improves. Intecells claim that cells produced with its process can achieve up to a 100% increase in energy and power density as a result. They also claim a 93% reduction in cell manufacturing cost and 50% overall reduction in battery pack cost per kilowatt-hour. The elimination of the drying and calendering process also reduces energy consumption by 90%.

So far, Intecells has only eight employees in Michigan, and they are able to produce sample pouch cells of about 3x3 inches for testing. They are working on scaling the production process and looking for partners that can develop a larger version of the cold plasma machinery used for electrode coating. Cofounder and CEO Dr. Xiaohong (Shawn) Gayden believes that integration into automotive scale production is possible by mid-decade. Intecells’ and Tesla’s innovations in battery manufacturing are likely to be just as important as chemistry advancements to getting EV prices down.