ANODE AND CATHODE SLURRY
Consistent Electrode Coating Increases Efficiency
How to convey anode and cathode slurries reliably and without bubbles
Manufacturing lithium-ion batteries requires maximum process stability and reproducible quality. How can production volume, despite tight tolerances, be increased while reducing maintenance costs and waste? Reliable conveying of the anode and cathode slurries to the coating machine is crucial, as even the smallest disruption has a direct impact on electrode quality.
As a global specialist in handling complex media, NETZSCH Pumps & Systems offers technically sophisticated solutions for high-precision coating processes. We will show you how a hermetically sealed progressing cavity pump can improve the cost-effectiveness and process reliability of your battery production.
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Complex conditions require maximum precision
The anode and cathode slurries are viscous mixtures containing abrasive solids. Typical viscosities are in the range of several thousand mPas, while at the same time, absolutely uniform delivery is required. Even the slightest pulsations or air entrainment lead to inhomogeneities in the coating, which adversely affect the quality and service life of the lithium-ion batteries. In addition, the fine solids place high demands on the pump’s sealing and wear parts. Abrasion, dead spaces that are difficult to clean, and the risk of metal abrasion directly impact product quality and service life. At the same time, maintenance and cleaning downtime must be kept to a minimum to ensure plant productivity.
If pulsation-free slurry conveyance isn’t enough
An American manufacturer of lithium-ion batteries used conventional progressing cavity pumps in its coating process. Although these pumps basically met the requirements for pulsation-free pumping, recurring problems arose during operation. Leaky mechanical seals led to high repair costs and considerable labour. Between production runs, the pumps had to be dismantled entirely to remove residues from closed areas. In addition, condensed gases entered the feed system. This resulted in air bubbles on the electrode surface, local indentations and coating defects.
Seal-free pump design for maximum battery quality
A NEMO® progressing cavity pump with a specially developed magnetic coupling was used to solve the challenges described. The innovative design of the NEMO® MY magnetically coupled pump eliminates the need for a conventional dynamic shaft seal. Torque is transmitted without contact, resulting in a hermetically sealed pump design. This reliably prevents the escape of medium or vapours, as well as the ingress of air into the delivery system. Air pockets caused by coating and the resulting surface defects are thus effectively avoided. The fully enclosed delivery chamber also prevents condensed gases from infiltrating the suspension. This ensures uniform, homogeneous delivery and contributes to the reproducible quality of the electrode coating. In addition, the pump is equipped with a CIP connection. CIP stands for “Cleaning in Place”. Cleaning is carried out by simply rinsing with a suitable cleaning solution, without dismantling. This significantly reduces downtime and the personnel required for maintenance and cleaning. Optional metal-free, wetted wear parts reliably prevent metallic abrasion particles from entering the electrode slurries. This increases process reliability and protects the sensitive electrode structure. The proven progressing cavity pump principle also ensures pulsation-free and precise conveying. Even at very low flow rates, constant-volume flow is achieved, guaranteeing uniform layer thicknesses and stable coating quality.
In early 2025, the manufacturer installed a NEMO® MY magnetically coupled pump in the coating system and conducted extensive tests to evaluate coating quality, pump performance and cost-effectiveness. The results showed a significant improvement in process stability and a measurable reduction in coating-related defects. In addition, maintenance-related downtime was significantly reduced. The annual savings in operating and maintenance costs exceed 23,254 US dollars per pump. Based on these results, the manufacturer decided to convert all coating pumps to magnetic coupling technology.
Contact the experts at NETZSCH Pumps & Systems to optimise your coating processes. We will be happy to assist you in designing and integrating the right pump solution.
NEMO® MY magnetically coupled pump
