Authors: Itziar Azpitarte, Unai Eletxigerra – Tekniker

With its research, BATMACHINE aims to make EU battery manufacturing more sustainable and less environmentally impactful. In this context, consortium partner Tekniker carried out initial coating trials and pilot studies. Specifically, Tekniker conducted the trials in their laboratory-scale slot-die pilot line. During these activities, Tekniker used a FOM-designed slot-die head, ensuring alignment with the full-scale coating machine being developed and delivered by FOM Technologies as part of the BATMACHINE project.

Tekniker’s Pilot Line is a flexible and modular research platform capable of operating in both Roll-to-Plate (R2P) and Roll-to-Roll (R2R) configurations. In fact, this setup allows precise adjustment of multiple coating parameters, providing valuable process insights for the project. The ability to test different coating heads and conditions is particularly important for evaluating various material formulations, such as new electrode chemistries and solid electrolytes, prior to scaling up on the final full-scale machine.

Tekniker Slot-die Pilot line – what does it do?

In the initial stage of the BATMACHINE research, the slurry has been fully characterised. More specifically, this operation included the evaluation of the rheology, visco-stability and solids content. As a result, the choice of the slot-die coating head fell onto FOM’s and its machinery. In fact, the FOM slot-die head appears to be the most suitable for this type of application. This is due to its effectiveness in applying high viscosity coatings and attributable to internal disengagement, capable of reducing dead volume.

The slot die moves on a guided carriage, which supports the various elements that constitute the pilot plant. Moreover, this assembly contains the syringe dosing system that controls the flow rate applied to the slot die. In addition, the two linear axes elevate and descend the head individually or jointly with an accuracy and repeatability of 0.1 microns.  Consequently, the dealignment between the slot-die and the substrates is practically non-existent. The carriage sits on a guided, supported system of skids that allow it to move through the two work areas. It is fixed by a mechanical stop and a confirmation micro to ensure that there are no problems of displacement.
The selection of working areas follows the requirements of the deposited materials. The R2P process involves mounting the flat substrate on a stainless-steel vacuum suction table with working widths ranging from 100 mm to 300 mm. On the other hand, the R2R process is carried out on a 15 cm reel. This comprises the loading centre area where the flexible substrate is coated and the uploading area.

Tekniker’s Contribution to Battery Manufacturing

All these process variables are controllable with an in-house automation software. This configuration facilitates the execution of any experimental design. In turn, this enables researchers to obtain the optimal working window. This is relevant because it ensures the quality of the deposition in post-lab tests, characterisation and so on. In summary, the Tekniker Slot-Die Pilot line demonstrated to be a valuable instrument for the development of electrode coating for lithium-ion batteries. The insights gained at this stage are essential to inform and accelerate the scale-up process. In fact, the final stage will be realised through the full-scale slot-die coating machine delivered by FOM Technologies.