In new energy battery manufacturing, electrode slurry filtration directly affects coating stability, electrode quality, equipment operation, and material utilization. Even small agglomerates, metal particles, dried slurry, or foreign contaminants can cause coating defects, unstable slurry delivery, filter blockage, and unnecessary material waste.

One battery manufacturer was experiencing unstable slurry feeding during the electrode coating process. The customer had already installed filtration equipment, but frequent fluctuations still occurred near the coating machine. The existing filtration arrangement could not effectively balance contaminant removal, flow stability, and filter service life.

Instead of simply recommending a finer filter cartridge, Pullner reviewed the customer’s actual production line, slurry circulation route, filtration positions, equipment arrangement, and operating problems. Based on the on-site analysis, Pullner proposed a combined filtration and pipeline optimization solution using a mesh filter cartridge for upstream protection and three PRI single-cartridge capsule filters installed in parallel before the coating machine.

The optimized system helped the customer improve coating stability, reduce slurry loss, protect production equipment, and lower the overall operating cost of battery manufacturing.

The customer used electrode slurry in a continuous battery coating process. During production, the slurry needed to pass through the delivery and filtration system before entering the coating machine.

However, several problems were affecting normal operation:

• Unstable slurry flow before the coating process

• Uneven coating performance caused by contaminants or agglomerates

• Rapid blockage of downstream filters

• Excessive pressure fluctuation in the slurry delivery line

• Frequent line stoppages for filter replacement and cleaning

• Slurry remaining inside filters and pipelines during maintenance

• Increased waste of high-value battery materials

The customer initially considered replacing the existing filter with a finer filtration product. However, using only a finer filter would not necessarily solve the problem. If large particles and agglomerates were not removed in advance, the final-stage filter could become blocked quickly, creating higher differential pressure and making slurry delivery even less stable.

Pullner therefore recommended evaluating the complete production line rather than focusing only on one filter cartridge.

Pullner’s technical team reviewed the customer’s slurry preparation, transfer, pre-filtration, circulation, and coating sections.

The analysis showed that the original filtration arrangement did not provide sufficient staged protection. Larger contaminants and slurry agglomerates were entering the downstream filtration section, increasing the load on the filters installed near the coating machine.

At the same time, the original pipeline configuration did not provide enough filtration capacity for stable continuous operation. When the downstream filter resistance increased, the slurry pressure and flow rate fluctuated, which affected the consistency of the slurry supplied to the coating machine.

The main issue was therefore not caused by a single filter cartridge. It was the combined result of filtration position, contaminant distribution, available filtration area, pipeline arrangement, and actual operating flow.

Based on these findings, Pullner developed a two-stage filtration solution together with a pipeline modification proposal.

The first improvement was to install a mesh filter cartridge upstream of the existing pre-filtration section.

The mesh filter cartridge was used to intercept larger particles, dried slurry fragments, agglomerates, and other coarse contaminants before they entered the downstream filtration system.

Compared with directly using a fine filter cartridge at this position, the mesh cartridge provided several practical advantages:

• High mechanical strength

• Low initial pressure drop

• Stable performance under slurry circulation conditions

• Effective removal of larger contaminants

• Reduced contaminant load on downstream filters

• Easy inspection and cleaning when required

• Longer service life for the final filtration stage

This upstream protection prevented coarse contaminants from rapidly blocking the filters near the coating machine. It also helped stabilize the differential pressure across the complete filtration system.

The filtration rating and structure of the mesh cartridge were selected according to the customer’s slurry characteristics, contaminant condition, flow requirement, and downstream filtration target.

The second improvement was made at the coating machine inlet.

Pullner recommended installing three PRI single-cartridge capsule filters in parallel before the slurry entered the coating machine. The parallel configuration increased the available filtration area and divided the total slurry flow among three filtration units.

Compared with a single filter line, the three-filter parallel arrangement provided several benefits:

• Lower flow load on each individual filter

• Reduced pressure drop across the filtration stage

• More stable slurry delivery to the coating machine

• Increased total dirt-holding capacity

• Longer filter service life

• Reduced frequency of production interruptions

• Easier maintenance and filter replacement

• Improved operating flexibility

The PRI capsule filter combines the filter cartridge and housing into an integrated filtration unit. Its compact structure helps reduce complicated installation work and makes filter replacement more convenient.

For battery slurry applications, the internal filter configuration can be customized according to the slurry composition, required filtration rating, viscosity, flow rate, pressure, temperature, and chemical compatibility requirements.

The parallel design was especially important in this project. Rather than forcing the complete production flow through one filter, the slurry was distributed through three PRI filtration units. This reduced the filtration resistance of each branch and supported a more stable supply to the coating process.

Product selection was only one part of the project. Pullner also assisted the customer in optimizing the filtration pipeline.

The modification focused on improving slurry flow distribution, reducing unnecessary retention areas, and ensuring that the three parallel filters operated under balanced conditions.

The optimization included reviewing:

• Filter installation positions

• Pipeline branch arrangement

• Inlet and outlet directions

• Flow distribution between parallel filters

• Valve positions

• Pressure monitoring points

• Filter replacement procedures

• Slurry drainage and recovery

• Cleaning and maintenance access

Balanced piping was important because an improperly designed parallel system can cause uneven flow distribution. One filter may carry a higher flow than the others, resulting in faster blockage and unstable operating pressure.

Pullner therefore considered both the filtration products and the actual pipeline arrangement. This allowed the three PRI capsule filters to work as one coordinated filtration stage instead of three independent filters with uneven loading.

The modified line also made maintenance more convenient and reduced the amount of slurry remaining inside the filtration system during filter replacement.

After the mesh pre-filter, three parallel PRI capsule filters, and optimized pipeline arrangement were installed, the customer carried out production testing under actual operating conditions.

The filtration system showed more stable pressure and flow performance. Larger contaminants were intercepted by the upstream mesh filter, while the PRI capsule filters provided controlled final filtration before the coating machine.

The customer reported clear improvements in the coating process:

• Slurry delivery became more stable

• Coating fluctuations were reduced

• Filter blockage occurred less frequently

• Production interruptions were reduced

• Slurry waste during maintenance decreased

• Downstream equipment received better protection

• Filtration operation became easier to manage

The optimized filtration line helped the customer reduce the loss of valuable battery slurry. It also reduced the indirect costs associated with coating defects, equipment cleaning, filter replacement, production downtime, and rejected electrode materials.

Most importantly, the project improved the stability of the complete coating line rather than solving only one temporary filtration problem.

The project was successful because the solution was based on the customer’s real production process.

Battery slurry filtration cannot be determined only by a filter model number or nominal micron rating. Slurry viscosity, solid content, particle distribution, agglomerate condition, flow rate, pressure, pipeline design, coating requirements, and cleaning procedures can all affect filtration performance.

Installing a finer filter without analyzing these conditions may result in rapid blockage, excessive pressure drop, short service life, and unstable slurry supply.

In this case, Pullner used a staged filtration strategy:

1. The mesh filter cartridge removed larger contaminants before pre-filtration.

2. Three parallel PRI capsule filters provided stable final filtration before coating.

3. The pipeline arrangement was modified to improve flow balance and maintenance conditions.

The combination of filtration products and engineering optimization allowed the customer to achieve a more practical and sustainable result.

Pullner provides customized filtration products and technical support for lithium-ion battery and new energy manufacturing processes, including:

• Cathode slurry filtration

• Anode slurry filtration

• Electrode coating line filtration

• Slurry transfer and circulation filtration

• Raw material pre-filtration

• Electrolyte filtration

• Process liquid filtration

• Cleaning liquid filtration

Available solutions include mesh filter cartridges, pleated filter cartridges, stainless steel filters, capsule filters, filter housings, and customized parallel filtration systems.

Pullner can evaluate the customer’s slurry properties, operating flow, filtration rating, pressure, temperature, existing equipment, pipeline dimensions, installation space, and filter replacement requirements before recommending a suitable solution.

Rather than selecting a filter only according to a model number, Pullner focuses on the complete filtration process. Sample testing and small-batch validation can also be arranged before full-scale production use.

For more information about battery slurry filtration and PRI capsule filter solutions, please visit www.pullnerfilter.com.