Contributed Commentary by David G. Malobicky, Swindell Dressler International
May 28, 2024 | Global lithium-ion battery production capacity is projected to increase eightfold by 2027 to nearly 9 TWh. The US is projected to have over 10% of this capacity in place, which is over a tenfold increase from today’s capacity.
Currently, the U.S. relies on international markets for the processing of most lithium-battery raw materials. These include critical minerals to produce battery components such as cathodes, anodes, and electrolytes. While clear advances have been made to manufacture these batteries domestically in the US, the ability to mine and process the critical raw materials in the US has been slow to advance.
Production of Lithium Battery Cathode Active Materials
A robust, secure, and domestic industrial base for lithium-ion batteries requires access to a reliable supply of raw, refined, and processed material inputs. The goal is to reduce U.S. dependence on scarce and foreign supplied cathode active materials to develop a stronger, more secure and resilient domestic supply chain.
These battery materials include lithium, cobalt, nickel, manganese, and iron phosphate among others, which must go through a precursor purification process for lithium batteries. This manufacturing process for battery cathode materials involves crucial steps known as Calcining and Sintering, where anode and cathode precursors undergo controlled high-temperature treatment to enhance their structural integrity and optimize electrochemical properties. Kilns, the workhorses of this process, play a pivotal role in providing the necessary controlled atmospheres and uniform heat distribution.
Therefore, kilns operating at high temperatures are critical to manufacturing the active powders required in lithium-ion batteries. The desired microstructure, morphology, particle size, and degree and type of possible contamination in the CAM powders play a decisive role in the type and function of the needed kiln.
Kiln Technology for Battery Active Materials
Kilns are used worldwide to produce finished materials for a wide range of products. While the processing of cathode materials at high production rates is relatively new, the cycles and conditions of heating and cooling have close relationships with many other ceramic and metallic materials.
Kiln designers must foster process development in this evolving technology by providing flexibility in design of heating and cooling rates, as well as the kiln atmosphere. In addition to meeting stringent process parameters, kiln designers must help determine the type of firing system required. There are two categories of firing, namely batch and continuous, each with certain advantages and disadvantages. However, due to the high throughput needs, only continuous kilns are considered for production scale battery materials.
Furthermore, there are 3 major configurations of continuous kilns mostly considered for processing such materials. They are Roller Hearth, Rotary, and Pusher Plate. The following is a brief description for each of these kiln designs.
Roller Hearth Kilns (RHK)
Roller Hearth Kilns consist of a driven roller conveyor that propels saggars (boxes) loaded with CAM material through the kiln. Cycle speed is governed by the speed of the conveyor, and application of heat energy is applied in multiple zones to create different rates of heating. Cooling is managed by removing heat through recirculation and heat exchange of internal kiln gases, sometimes combined with water jacketed portions of the cooling segment. Energy efficiency is quite good since the temperature of the kiln within each zone is maintained continuously.
Rotary Kilns (RK)
Rotary Kilns utilize a simplistic design where products are continuously fed into a rotating, inclined cylinder, and proceed through the kiln gradually due to the tumbling action and incline angle. The cylindrical drum is heated from the outside through various means (fossil fuel combustion or resistance heating). Atmosphere is injected into the drum to provide the required atmosphere. The entry and exit of the kiln is sealed to avoid air infiltration and excessive atmosphere leakage.
Pusher Plate Kilns (PPK)
Pusher Plate Kilns are similar to RHK’s, but the transport of product through the kiln is simpler. The PPK pushes the saggars on ceramic pallets or plates at the entry of the kiln tunnel. These plates slide on a hearth of alloy or ceramic, The PPK embodies similar heating and cooling advantages as in the RHK. Sliding friction of the plates tends to limit the maximum load applied to the plates since they are pushed through the kiln as opposed to being propelled by a conveyor. On the other hand, PPK’s do not require complicated roller drive systems and are relatively easy to seal against air infiltration.
Conclusion
Unprecedented electric vehicle demand, along with a significant increase in government spending and new regulations, have driven the US battery industry to new heights. To meet these growing demands and regulations, and to meet strict cost targets to make the investments attractive, domestic raw material and manufacturing equipment availability are critical. However, the US currently lacks a robust and secure supply of lithium batteries. Consequently, the country relies heavily on imports and accounts for only 30% of the value-added in lithium batteries that are consumed in the US.
To address this situation the US Department of Energy launched Li-Bridge, a project that brings together US lithium battery technology experts. Their mission: to devise a strategy for a robust, sustainable lithium battery supply chain for North America. Li-Bridge has established a 2030 goal for the US lithium battery industry: to double current value capture, such that the US will increase its domestic stake of the US market to 60%. This would add $17 billion in direct value and 40,000 direct jobs.
To successfully achieve the Li-Bridge goals, all aspects of the battery manufacturing process must be considered for domestication, including the much overlooked midstream and upstream manufacturing equipment. One of the key steps in the midstream processing of critical Cathode Active Materials is converting precursor metals into CAMs during the sintering process utilizing custom designed kilns. As such, sourcing these kilns in the US for the increasing domestic battery production demand will be a critical success factor. However, the equipment capacity to support this demand with local suppliers is being compromised by economically advantaged foreign suppliers. Therefore, the US related government funding initiatives, which have to date mainly focused on promoting the availability and domestication of critical battery raw materials, should also focus on promoting and assisting domestic sources for critical upstream and midstream manufacturing equipment.
David G. Malobicky is currently the President of Swindell Dressler International, a US based company specializing in the design, manufacture, and installation of large industrial kilns used to support a wide range of industries. Prior to Swindell Dressler David had spent most of his career with PPG, a global supplier of paints, coatings, and specialty materials. Highlighted roles include Global Director – New Energy. In this role, David was responsible for defining growth initiatives within the emerging Energy Transition sector. David also led PPG’s Mobility segment focusing on advantaged products targeting the production of lithium-ion batteries and packs for the electrification of the global transportation sector. He also previously served as the General Manager of PPG’s global Electronic Materials business. He can be reached at dmalobicky@swindelldressler.com.
