Photo by CDC on Unsplash
In a recent Barry on Batteries column in Chemical Processing, I tried to convey the complexity involved in lithium-ion battery cell manufacturing. To illustrate how this complex process involves numerous steps, requiring specific techniques and tailored approaches to ensure quality and functionality, I explored topics such as material quality, in-process testing, and control measures.
The article further compared manufacturing lithium-ion battery cells to the complexity of synthesizing Active Pharmaceutical Ingredients (APIs). A complex API might involve up to 36 steps while an “easy” specialty chemical might require 15 steps with various chemical combinations, process parameters and by-products. Battery processing isn’t that far behind.
Battery Complexity Compared to Pharmaceuticals
I’m sure that you are thinking that “a battery is a battery,” but this is not the case. Synthesis of the cathode active material is very complex along with the anode material, separators and electrolytes. The actual assembly of the cell battery is also complex. The 11 different steps in lithium-ion battery cell manufacturing, outlined below, also include many sub-steps.
- Slurry Mixing: The cathode slurry and anode slurry is formed.
- Coating: The specific cathode slurry is applied to the carbon-coated aluminum foil while the anode material is applied to the copper foil.
- Drying: The solvent present in the electrode coating needs to be removed through a drying process.
- Calendaring: The anode and cathode electrode sheets are compressed to ensure a consistent thickness.
- Slitting & Notching: Slitting involves precise cutting into multiple strips while notching forms the positive and negative terminals.
- Stacking & Winding: The stacking and winding process puts the cell together by layering the cathode foils, anode foils and separator layer.
- Cell Assembly: The cell assembly process has approximately seven sub-steps before the electrolyte is added.
- Electrolyte Filling: The filling step is critical to ensure complete wetting of the positive and negative electrodes.
- Formation & Aging: Forming refers to the electrochemical activation that results in the Solid Electrolyte Interface (SEI) on the anode electrode while the aging process is a storage time to stabilize the SEI and testing to ensure the cells meet the quality for capacity, voltage and cycle life.
- Final Testing: Completed cells are checked and certified.
- Module Assembly: Cells are shipped for assembly into the modules.
Applying API sophistication
Furthering the parallels with pharmaceuticals, the battery cell manufacturing process also demands testing and quality control, precise data collection and thorough inspections. All this helps ensure batteries meet the high standards for electric vehicle use.
Ultimately, the lithium value chain must act like a sophisticated chemical plant. P&ID has had the privilege already to work with many clients to streamline their processes, ensure the right technology is selected, and discuss safety and testing protocols. Want to discuss what we can do for your process? Contact me today!