Challenges during lithium-ion cell manufacturing plant set up – Part 5

Process optimisation and skilled workforce

Rahul Bollini is writing a series of articles explaining the challenges faced during Lithium-ion cell manufacturing plant setup, which should be relevant to any company entering this field. This article (part 5 of the series) explains the challenges faced during the cell manufacturing plant setup with respect to process optimisation and skilling of the workforce.

As discussed earlier, any company entering into Lithium-ion cell manufacturing establishes a laboratory setup to get its team acquainted with the complexity of the Lithium-ion cell manufacturing process. This laboratory setup is scaled up to pilot scale (usually MWh size) and later scaled all the way to Giga scale. One fully automated end-to-end equipment line can cater up to a few GWh.

At each of these stages, there can be a few challenges related to process optimisation. Process optimisation means tuning the production process with respect to the equipment to get the desired output. It also means dealing with accuracy problems every now and then with the right troubleshooting steps. It takes specialised expertise to handle process optimisation tasks. This article talks about process optimisation related to various aspects of cell manufacturing.

Workforce

The workforce challenges can be divided into two categories – upskilling and strict QC (quality control) practices to be followed in cell manufacturing. This challenge is alike for every advanced technology field that is newly emerging.

Upskilling – Upskilling simply means acquiring the skills (basic, intermediate and advanced) required for a particular job. This can involve a mix of theoretical and practical training sessions. It is a challenge to find institutions (educational or industrial) that can provide the right skill development guidance for a newly emerging and highly technical field such as cell manufacturing.

Hence, cell manufacturing companies consider sending their first set of employees (from chemical, electrochemical, mechanical, mechatronics, electronics and electrical fields) to their technology partner company (usually outside India) for hands-on training. Due to the high training costs involved in specialisation training, these companies try their best to retain such employees for as long as possible. Maintenance personnel can be hired from a different field, such as Pharma, where the operations for the equipment, dry room and total plant maintenance are similar.

QC Practices – Quality Control is by far the most important aspect of cell manufacturing. Neglecting quality practices during cell manufacturing can have serious implications on the production output, including a high rejection rate during cell grading. There can also be long-term issues on the field, such as cell failures, dangerous incidents and even fire in certain cell chemistries. Adhering to a strict QC process must come from personnel certified in six sigma and other QC certifications.

QC is very important in incoming raw material inspection, process control and monitoring parameters during production, grading and pre-dispatch inspection. It is also relevant to maintain the right ambient working conditions in raw material storage and cell production area in terms of relative humidity, dew point temperature and cleanliness as any foreign particle can potentially disturb the production process.

QC and process optimisation

QC not only involves keeping the environment clean but also getting the process right. Here are the processes that require strict adherence to standard operating procedures.

• Studying the incoming raw material, e.g. analysing active material in SEM and XRD. There are different processes for checking other raw materials and looking for moisture content.

• Composition of electrode (cathode & anode) slurry mix consisting of active material, binder, additive and solvent. The binder needs to blend well in the solvent, and the additive needs to disperse well on the active material.

• Consistency of the slurry material while prepping for coating in terms of viscosity, etc.

• Consistency of the slurry thickness while coating, after drying and calendaring.

• Maintaining a consistent measurement and looking for burr (a rough edge left on metal after cutting) in daughter coils after slitting from the mother coil.

• Static removal in the separator to ensure that it is not carrying any charge.

• Uniform winding (cylindrical and prismatic) or stacking (pouch) to ensure proper alignment of the electrodes with respect to the separator.

• High-accuracy electrolyte filling (less filling can’t ensure proper wettability)

• Strict protocols of cell formation (an important aspect for first-time cell activation).

• Having a regular cleaning system until the cell is closed to ensure no contamination.

• Strictly maintained conditions for dry room (cell production), cell ageing and cell storage areas.

Neglecting any of the aforementioned procedures may compromise the output, resulting in a higher number of lower-grade cells that can only be sold at prices lower than the market rate. The results are usually evident while studying the self-discharge (voltage drop) of the cells after activating them and putting them for ageing under high temperature and normal temperature room for a defined period of time.

A newly set up plant has a low output of high-quality cells initially. Regular process optimisation and finetuning over certain months ensures that the output of high-quality cells steadily goes up to an acceptable level. Quality control plays a vital role in this whole process.

Upcoming parts of this series:

• Part – 6 (Expansion and Diversification of Portfolio)

• Part – 7 (Evolving to Newer Technologies)

• Part– 8 (Backward Integration)

Rahul Bollini is an R&D expert in Lithium-ion cells with 8 years of experience. He founded Bollini Energy to assist in deep understanding of the characteristics of Lithium-ion cells to EV, BESS, BMS and battery data analytics companies across the globe. Rahul can be reached at +91-7204957389 and bollinienergy@gmail.com.

Also Read:

Part 1 Understanding the market

Part 2 Product meeting technical expectation of the market

Part 3 Possibility of localisation, and securing raw materials

Part 4 Plant set up planning

Part 6 Expansion and diversification of portfolio

Part 7 Evolving to Newer Technologies

Part 8 Backward Integration