1. Industry Background and Challenges‌

In mining and metallurgical production processes, large volumes of corrosive media—such as acidic solutions, alkaline liquids, and organic solvents—must be handled. These substances are not only highly corrosive but may also contain solid particles or other impurities, imposing stringent demands on pump materials, sealing performance, and operational stability. Selecting the appropriate pump solutions is critical to ensuring continuous and safe production.

2. Overview of Anhui Changyu Pump & Valve Solutions‌

Anhui Changyu Pump & Valve Manufacturing Co., Ltd. has developed a range of specialized pump products tailored to the unique demands of the mining and metallurgical industries. Below are the key pump solutions offered:

‌2.1. Corrosion-Resistant Magnetic Drive Pumps‌

• ‌Working Principle‌: Utilizes magnetic coupling technology to eliminate mechanical seals, ensuring leak-free operation.
• ‌Materials & Applicable Media‌: Constructed with high-performance corrosion-resistant alloys (e.g., 304, 316, 316L stainless steel, Hastelloy), ideal for handling highly corrosive fluids.
• ‌Advantages‌: Compact design, smooth operation, and suitability for diverse corrosive media in mining and metallurgical processes.

‌2.2 Plastic-Lined Slurry Pumps‌

• ‌Applications‌: Designed for corrosive slurries such as phosphoric acid slurry and fluorosilicic acid slurry.
• ‌Features‌: Plastic-lined interior for enhanced corrosion resistance, combined with superior abrasion resistance for particle-laden media.
• ‌Advantages‌: Easy maintenance and reliable performance, making them ideal for slurry transportation in mining and metallurgy.

‌2.3 Stainless Steel Centrifugal Pumps‌

• ‌Materials‌: Premium stainless steel construction for excellent corrosion and high-temperature resistance.
• ‌Applications‌: Suitable for seawater, brine, organic solvents, and other corrosive media at varying concentrations.
• ‌Advantages‌: Compact structure, high efficiency, and versatility for diverse corrosive fluid handling needs in the industry.

3. Detailed Application Scenario Analysis‌

‌3.1. Ore Processing‌

• ‌Process Description‌: Involves crushing, grinding, and leaching of ores, requiring handling of large volumes of corrosive media.
• ‌Pump Selection‌: Corrosion-resistant magnetic drive pumps and stainless steel centrifugal pumps are ideal for ore processing, ensuring stable transportation and leak prevention.

‌3.2 Flotation Separation‌

• ‌Process Description‌: Separates valuable minerals from waste rock via flotation technology, involving corrosive reagents.
• ‌Pump Selection‌: Plastic-lined slurry pumps excel in flotation due to their corrosion and abrasion resistance.

‌3.3 Smelting & Extraction‌

• ‌Process Description‌: Operates in high-temperature, high-pressure environments with corrosive media.
• ‌Pump Requirements‌: Pumps must resist corrosion, high temperatures, and pressure. Magnetic drive pumps and stainless steel centrifugal pumps are preferred for their superior performance.

‌3.4 Tailings Treatment‌

• ‌Process Description‌: Handles slag and tailings containing solid particles and acidic waste liquids.
• ‌Pump Selection‌: Plastic-lined slurry pumps, balancing corrosion and abrasion resistance, are optimal for tailings processing.

3.5 Cooling Circulation‌

• ‌Process Description‌: Requires corrosion-resistant cooling media circulation in smelting.
• ‌Pump Requirements‌: Pumps must resist corrosion and ensure long-term stability. Stainless steel centrifugal pumps are well-suited for this application.

4. Conclusion‌

Leveraging extensive expertise and cutting-edge technology in pump and valve manufacturing, Anhui Changyu Pump & Valve Manufacturing Co., Ltd. delivers a comprehensive range of high-efficiency, reliable pumping solutions tailored for the mining and metallurgical industries. These solutions not only address the industry's specialized requirements for handling corrosive media but also enhance operational stability and safety in production processes.

Moving forward, as technology evolves and industry demands continue to shift, Anhui Changyu Pump & Valve remains committed to innovation and R&D, striving to provide the mining and metallurgical sectors with superior pump products and technical services.

I. Characteristics and Advantages of Polyacrylate (PAA) Binders

1. Minimal Swelling in Electrolyte Solvents: Exhibits low swelling, maintaining structural integrity of electrode sheets during charge/discharge cycles.
2. High Proportion of Carboxyl Groups: The high density of polar carboxyl groups forms strong hydrogen bonds with hydroxyl-containing active materials, enhancing dispersion stability.
3. Continuous Film Formation: Creates a uniform film on material surfaces, improving contact between active materials and current collectors.
4. Excellent Mechanical Stability: Facilitates ease of processing during electrode manufacturing.
5. Enhanced SEI Formation and Cycling Performance: The high concentration of polar functional groups promotes hydrogen bonding with silicon material surfaces and aids in forming a stable Solid Electrolyte Interphase (SEI) layer, resulting in superior cycle life.

II. Development Challenges

Conventional PAA (Polyacrylic Acid) binder systems for electrodes typically utilize cross-linked PAA polymers as the anode binder. As a high-molecular-weight polymer, PAA offers excellent adhesion, dispersion stability, and corrosion inhibition. It stabilizes the network structure within the anode slurry, ensures uniform dispersion of active materials, and extends electrode sheet lifespan.

• However, the polar functional groups facilitate hydrogen bonding within the long molecular chains of PAA. This restricts free rotation of the chains, increasing their rigidity. Consequently, PAA-based electrode sheets generally exhibit poor toughness. This compromises their ability to withstand stresses induced by the volume expansion of active materials during cycling, hinders cell winding processes, and ultimately limits improvements in battery electrochemical performance.

III. Research Practices in Practical Applications of Battery-Grade PAA

1. Sodium-Ion Battery Hard Carbon Anodes

Manufacturers of hard carbon anodes for Sodium-Ion Batteries (SIBs) impose stringent requirements on PAA binders. A high-quality, highly flexible PAA binder is crucial for protecting the structural integrity of hard carbon anodes.

• In the current SIB hard carbon anode market, using substandard PAA binders significantly increases the risk of elevated internal resistance, negatively impacting battery efficiency and reliability. Conversely, a premium, highly flexible PAA binder effectively mitigates these issues.
• The electrochemical performance, conductivity, environmental adaptability, and corrosion resistance of the flexible PAA binder are also critical factors, directly influencing the quality of the final hard carbon anode product.
• Beyond inherent characteristics, practical application focuses heavily on performance parameters such as binder characteristics, solid content, adhesion strength, and pH level. These parameters directly correlate with the operational efficiency of the hard carbon anode.

2. Silicon-Based Anodes

Silicon-based lithium-ion battery anodes offer a specific capacity an order of magnitude higher than conventional graphite. However, forming stable silicon anodes is challenging due to significant volume changes during the electrochemical alloying/dealloying of silicon with lithium. Binder selection and optimization are vital for improving silicon anode stability. Most research utilizes Carboxymethyl Cellulose (CMC) and Polyvinylidene Fluoride (PVDF) binders.

• A significant body of experimental research indicates that pure PAA possesses mechanical properties comparable to CMC but contains a higher concentration of carboxyl functional groups. This enables PAA to act as a binder for Si anodes, delivering superior performance.
• Research further demonstrates the positive impact of carbon coating on anode stability. Carbon-coated Si nanopowder anodes (tested between 0.01 and 1 V vs. Li/Li+), incorporating PAA at levels as low as 15 wt%, exhibit exceptional stability over the first 100 cycles. These findings open new avenues for exploring novel binders like the Polyvinyl Alcohol (PVA) series.
• Crosslinking PAA with other materials represents a new development direction, including AA-CMC cross-linked binders, PAA-PVA cross-linked binders, PAA-PANI (Polyaniline) cross-linked binders, and EDTA-PAA binders.

3. PVA-g-PAA (PVA-grafted-PAA)

A novel water-soluble binder, PVA-g-PAA, is synthesized by grafting PAA onto the side chains of highly flexible PVA (Polyvinyl Alcohol). This functional group modification enhances the flexibility of the PAA binder system while leveraging PVA's excellent adhesion properties.

• This free-radical grafting polymerization introduces elasticity, compensating for the structural limitations of pure PAA binders.
• During electrode sheet fabrication, rolling compaction is performed continuously using varying roller pressures across defined length segments of the sheet. This process enhances sheet toughness, minimizing deformation, increasing electrode specific capacity, improving rate capability, and extending battery cycle life.

4. PAA Prelithiation (LiPAA)

The application of silicon-carbon (Si-C) materials imposes higher demands on anode binder and conductive agent systems. Traditional rigid PVDF binders are unsuitable for Si anodes. Acrylic PAA binders contain numerous carboxyl groups capable of forming hydrogen bonds with functional groups on Si surfaces, promoting SEI formation and significantly improving the cycle life of Si anodes. Thus, PAA binders are highly effective for Si anodes.

• Studies indicate that Lithium Polyacrylate (LiPAA) outperforms PAA itself, although the underlying reasons were unclear. Extensive research has been conducted to elucidate the mechanism behind LiPAA's superior performance.
• Electrodes composed of 15% nano-Si, 73% artificial graphite, 2% carbon black, and 10% binder (either PAA or LiPAA) were studied. After initial drying, a secondary drying step at 100-200°C was performed to remove residual moisture completely. Coin cell testing revealed capacities of ~790 mAh/g for LiPAA-based anodes versus ~610 mAh/g for PAA-based anodes.

Cycle performance curves of full cells using NMC532 cathodes

• Figure A: Cells with LiPAA binder show no significant correlation between cycle performance and secondary drying temperature. The NMC532 cathode delivered an initial capacity of 127 mAh/g at C/3, declining to ~91 mAh/g after 90 cycles.
• Figure B: Cells with PAA binder exhibit a clear dependence on secondary drying temperature (120°C red, 140°C gold, 160°C green, 180°C blue). While the 160°C dried PAA cell showed the highest initial capacity and the 120°C dried cell the lowest, the 160°C dried cell degraded fastest, reaching ~62 mAh/g after 90 cycles. The 140°C dried cell degraded slower, maintaining ~71 mAh/g.
• First-cycle Coulombic Efficiency (CE): LiPAA cells achieved ~84% (only the 200°C LiPAA cell was slightly lower at ~82%). Their Coulombic efficiency rapidly increased to ~99.6% within the first 5 cycles. PAA cells achieved ~80% first-cycle CE (only the 180°C PAA cell was significantly lower at ~75%), requiring ~40 cycles to reach 99.6% CE – markedly slower than LiPAA cells.
• Pulse discharge tests at 50% Depth of Discharge (DOD) revealed significantly lower internal resistance in LiPAA cells compared to PAA cells [Referenced Figure Below], with no apparent link to secondary drying temperature for LiPAA. In contrast, PAA cell resistance increased noticeably with higher secondary drying temperatures.

• Thermogravimetric Analysis (TGA) by Kevin A. Hays [Referenced Figure Below] on LiPAA and PAA anodes identified two main dehydration steps: 1) Free water removal (~40°C), 2) Adsorbed water removal (LiPAA ~75°C, PAA ~125°C). Additional weight loss peaks occurred for PAA between 140-208°C and LiPAA between 85-190°C, attributed to polymerization of some carboxyl groups releasing water [Referenced Reaction Below]. This reaction is less pronounced in LiPAA, where Li replaces H in ~80% of carboxyl groups.

• High-temperature polymerization of PAA carboxyl groups may weaken the interaction between PAA and Si, potentially explaining the poor cycle performance of high-temperature dried PAA anodes. However, peel strength tests showed that while PAA adhesion decreased with higher drying temperatures, it remained higher than LiPAA overall, suggesting other factors contribute to LiPAA's superior cycling.

Ⅳ. Conclusion

This study identifies poor electrochemical stability as a key factor limiting PAA's cycle performance. At low potentials, PAA undergoes partial conversion to LiPAA, generating hydrogen gas:

PAA + ... -> LiPAA + H₂

This reaction explains the lower first-cycle CE of PAA cells (~80%) compared to LiPAA cells (~84%), and the significantly longer time (~40 cycles vs. <5 cycles) required for PAA cells to achieve high Coulombic efficiency (99.6%).

TOB NEW ENERGY - Your Professional Partner in Battery Materials, Equipment, and Production Line Solutions.

In lithium-ion battery manufacturing, the fineness of the slurry (mainly referring to the electrode slurry) is a key parameter affecting electrode performance (such as capacity, rate capability, cycle life, safety) and process stability. Different battery types have significantly different fineness requirements for the slurry (usually measured by particle size distribution indicators such as D50, D90, Dmax), due to the intrinsic characteristics of their positive/negative electrode active materials (such as crystal structure, ionic/electronic conductivity, specific surface area, mechanical strength, reactivity) and different requirements for electrode microstructure.

The following is a detailed analysis of slurry fineness requirements for major battery types:

I. Lithium Cobalt Oxide (LCO) Batteries

1. Material Characteristics:

Layered structure (R-3m), high theoretical capacity (~274 mAh/g), high compaction density, but relatively poor structural stability (especially at high voltages), moderate cycle life and thermal stability, high cost.

2. Fineness Requirements):

High fineness is required. Typically requires D50 in the range of 5-8 μm, D90 < 15 μm, maximum particle size Dmax < 20-25 μm.

3. Reasons:

• High rate performance: Finer particles shorten the lithium-ion diffusion path within the particles, facilitating high-rate charging and discharging.
• High compaction density: Fine particles can pack more tightly, increasing the electrode's compaction density and volumetric energy density.
• Reducing side reactions/Improving cycling: Small and uniform particles help form a more uniform solid electrolyte interphase (SEI) film, reducing cracks caused by localized stress concentration in large particles and side reactions with the electrolyte, improving cycle stability (especially at high voltages).
• Reducing polarization: Reducing particle size can lower charge transfer resistance and concentration polarization.

II. Lithium Iron Phosphate (LFP) Batteries

1. Material Characteristics:

Olivine structure (Pnma), extremely stable structure (strong P-O bonds), long cycle life, excellent thermal safety, low cost. However, both electronic conductivity and ionic conductivity are low, compaction density and voltage plateau are low.

2. Fineness Requirements:

Very high fineness is required. Typically requires D50 in the range of 0.2-1.0 μm (200-1000 nm), D90 < 2-3 μm. This is the highest fineness requirement among all mainstream lithium-ion battery cathode materials.

3. Reasons:

• Overcoming intrinsic low conductivity: This is the core reason. LFP's extremely low electronic and ionic conductivity is the main bottleneck for its performance. Nanosizing it (D50<1μm) is a key strategy to improve rate capability, significantly shortening the transport paths of electrons and lithium ions.
• Improving rate performance: Nanoparticles enable high-rate charge/discharge capability.
• Improving tap/compaction density: Although nanoparticles themselves have low tap density, through reasonable particle morphology (such as spheroidization) and slurry/electrode processes, fine primary particles can fill better, improving electrode compaction density (though still lower than LCO/NCM).
• Fully utilizing capacity: Ensures all particles can fully participate in the electrochemical reaction, avoiding unreactive "dead zones" inside large particles.

III. NCM Batteries (LiNiₓCoᵧMn₂O₂)

1. Material Characteristics:

Layered structure (R-3m), combines the high capacity/high voltage of lithium cobalt oxide, the high capacity of lithium nickelate, and the stability/low cost of lithium manganate. Performance (energy density, rate capability, cycle life, safety, cost) depends on the specific ratio (e.g., NCM111, 523, 622, 811). Higher nickel content leads to higher capacity and energy density, but greater challenges in structural stability and safety.

2. Fineness Requirements:

High fineness is required, but specific requirements become stricter with increasing nickel content.

• Medium/Low Nickel (e.g., NCM523 and below): D50 typically 6-10 μm, D90 < 18-22 μm.
• High Nickel (e.g., NCM622, 811, NCA): D50 requires finer particles, typically 3-8 μm (especially 811/NCA tends to be finer), D90 < 12-15 μm, strict control of Dmax < 20 μm.

3. Reasons:

• High energy density/rate performance: Fine particles help increase compaction density and rate performance (shortening Li⁺ diffusion path).
• Improving structural stability of high-nickel materials: High-nickel materials (high reactivity) are more prone to structural degradation (e.g., phase transition, microcracks) during cycling.
• Fine and monodisperse particles can: Reduce stress concentration within particles and crack initiation/propagation.
• Form a more uniform and stable CEI film, reducing electrolyte consumption and transition metal ion dissolution.
• Mitigate particle pulverization during cycling, improving cycle life.
• Reduce interfacial impedance/polarization: Similar to LCO.
• Safety considerations: Finer particles have relatively better heat dissipation and more stable structure, helping to improve safety (especially for high-nickel materials).

IV. NCA Batteries (LiNiₓCoᵧAl₂O₂)

1. Material Characteristics:  Very similar to high-nickel NCM (high capacity, high energy density). Aluminum doping aims to improve structural stability and cycle performance, but processing challenges (e.g., sensitivity to humidity) and safety challenges remain.

2. Fineness Requirements:

Very high fineness is required, close to or equivalent to high-nickel NCM (e.g., 811). D50 typically 3-7 μm, D90 < 12-15 μm, strict control of Dmax.

3. Reasons:

Identical to high-nickel NCM. The core lies in maximizing structural stability, cycle life, and safety through nano-sizing/fine particles while pursuing high energy density.

V. Lithium Titanate (LTO) Batteries)

1. Material Characteristics:

Spinel structure (Fd-3m), used as anode. Has "zero-strain" characteristic (minimal volume change), ultra-long cycle life (over 10,000 cycles), excellent rate capability and low-temperature performance, extremely high safety. However, high operating voltage (~1.55V vs Li+/Li) leads to low full-cell voltage and low energy density.

2. Fineness Requirements:

Medium to fine fineness is required. D50 typically in the range of 1-5 μm, D90 < 10-15 μm. Coarser than LFP, possibly slightly finer or comparable to some NCM/LCO.

3. Reasons:

• High-rate performance: LTO itself has good conductivity, but fine particle size is still an effective means to improve ultra-high-rate performance (e.g., fast charging), shortening the Li⁺ solid-phase diffusion path.
• Increasing compaction density: Although LTO is "zero-strain", increasing compaction density still helps improve volumetric energy density (despite its low absolute value).
• Reducing electrode impedance: Fine particles facilitate the formation of a tighter conductive network.
• Balancing processability and performance: Excessively fine LTO nanoparticles have a huge specific surface area, which significantly increases slurry viscosity, reduces solid content, increases binder/conductive agent usage, and exacerbates side reactions with the electrolyte (although LTO is stable, nano-sizing increases surface activity). Therefore, the fineness requirement is a balance between high-rate performance and processability/cost.

VI. Solid-State Batteries (SSBs)

1. Important Note:

"Solid-state batteries" cover various technical routes (polymer, oxide, sulfide electrolytes), and the choice of positive/negative electrode materials is also diverse (can be any of the above materials or new materials such as lithium-rich manganese-based, lithium metal anode). The requirements for slurry fineness are extremely complex and highly dependent on the specific system, but there are some common trends.

2. Core Challenge:

Solid-solid interfacial contact. In liquid batteries, the electrolyte can wet and fill pores, while the solid electrolyte is rigid particles, and point contact with active materials leads to huge interfacial impedance. This is one of the core challenges of solid-state batteries.

3. Fineness Requirement Trends:

• Generally higher fineness is required: Both active material and solid electrolyte particles usually require finer particle size (D50 often in the sub-micron to micron range).
• Reasons:

(1) Increasing solid-solid contact area: Fine particles provide a larger contact interface, reducing interfacial impedance.

(2) Shortening ion transport path: Fine particles can shorten the Li⁺ transport distance within the active material and solid electrolyte, and at the interface between them.

(3) Achieving more uniform composite: When preparing composite electrodes (active material + solid electrolyte + conductive agent + binder), the particle size and morphology matching of each component is crucial. Usually, all components need to achieve comparable fineness levels to mix uniformly and form effective ionic/electronic conductive networks.

4. Specific System Differences:

• Sulfide solid-state batteries: Highest fineness requirements. Sulfide electrolytes (e.g., LPS) usually need to be made into sub-micron or even nano-sized particles (D50 < 1 μm), active materials also often need to be nano-sized, and extremely uniform mixing (often using high-energy ball milling) is required to form a good ion-percolating network. Maximum particle size control is very strict.
• Oxide solid-state batteries: Electrolytes (e.g., LLZO) are usually hard and have larger particle sizes (micron level). To improve contact, active materials (especially the cathode) also tend to use smaller particles (e.g., D50 1-5 μm), and may require the introduction of a small amount of polymer binder or liquid wetting agent (quasi-solid). High requirements for mixing uniformity.
• Polymer solid-state batteries: The process is relatively close to traditional liquid batteries. Polymer electrolytes have a certain fluidity after heating. The fineness requirements for active materials are similar to or slightly higher than the corresponding liquid systems (e.g., using LFP, NCM), mainly for better interfacial contact and ion transport. The fineness of the polymer electrolyte itself (e.g., PEO particles) also needs to be controlled.
• Anode (e.g., lithium metal, silicon-based): If lithium metal foil is used, there is no slurry fineness requirement. If composite anodes are used (e.g., pre-lithiated silicon/graphite mixed with solid electrolyte), the fineness and mixing uniformity requirements for silicon particles and solid electrolyte particles are extremely high.

VII. Summary and Key Points:

1. Most Stringent Requirements:

Lithium iron phosphate requires the highest fineness (nanoscale) due to its intrinsic low conductivity. High-nickel ternary (NCM811/NCA) and active materials/electrolytes in sulfide solid-state batteries also require very high fineness (sub-micron to microns).

2. High Fineness Requirements:

Lithium cobalt oxide, medium/low-nickel ternary, and active materials in oxide/polymer solid-state batteries usually require high fineness (D50 several microns) to improve energy density, rate performance, and stability.

3. Moderate Fineness Requirements:

Lithium titanate requires medium to fine fineness (D50 1-5 μm), balancing rate performance and processability.

4. Core Driving Factors:

• Overcoming material intrinsic defects: The low conductivity of LFP is the most typical example requiring ultrafine particles.
• Improving kinetic performance (rate capability): Almost all materials need to reduce particle size to shorten ion diffusion paths.
• Increasing energy density (compaction density): Fine particles facilitate tight packing (especially for LCO, NCM).
• Improving structural stability and cycle life: Particularly important for layered materials (LCO, NCM, NCA). Fine particles can reduce stress cracks and side reactions. This is the key reason why high-nickel materials pursue finer particles.
• Optimizing solid-solid interface (solid-state batteries): This is the core requirement distinguishing solid-state batteries from liquid batteries, universally driving the demand for finer particles and more uniform mixing.

5. Trade-off Considerations:

Fineness is not always finer the better. Excessively fine particles can cause:

• Dramatically increased specific surface area -> High slurry viscosity, difficult dispersion, low solid content, increased binder/conductive agent usage -> Increased cost, greater process difficulty, potential reduction in energy density.
• High surface activity -> Aggravated side reactions (consuming electrolyte/lithium source, gas generation), cycle performance may instead decrease (especially for highly reactive materials like high-nickel).
• Severe particle agglomeration -> Affects uniformity and performance

Therefore, the optimal slurry fineness for each battery material is the result of meticulous trade-offs and optimization between its material characteristics, performance targets (energy, power, lifespan, safety), and process feasibility/cost. Manufacturers usually determine the most appropriate fineness control range based on specific material suppliers, formulation design, process equipment, and product positioning.

At TOB NEW ENERGY, we are committed to being your strategic partner in advancing energy storage technologies. We empower next-generation lithium battery production through precision battery mixing systems, electrode preparation systems, battery assembly line, intelligent battery production lines, and high-performance battery materials.  Our offerings extend to cutting-edge battery manufacturing equipment and battery tester, ensuring seamless integration across every stage of battery production. With a focus on quality, sustainability, and collaborative innovation, we deliver solutions that adapt to evolving industry demands. Whether you’re optimizing existing designs or pioneering next-generation batteries, our team is here to support your goals with technical expertise and responsive service. Let’s build the future of energy storage together. Contact us today to explore how our integrated solutions can accelerate your success.

In lithium battery manufacturing, the often-overlooked A/B-side coating misalignment issue during the coating process significantly affects battery capacity, safety, and cycle life. Misalignment refers to inconsistencies in the positional alignment or thickness distribution of coatings on the front and back sides of electrodes, which can lead to risks such as localized lithium plating and mechanical damage to the electrodes.

This article analyzes the root causes of misalignment from perspectives including equipment precision, process parameter settings, and material properties, while proposing targeted optimization strategies to help enterprises enhance product consistency and stability.

Ⅰ. Causes of A/B-Side Misalignment

1. Equipment Factors

Insufficient roll system assembly accuracy: Horizontal or coaxial deviations during the installation of backing rolls and coating rolls may cause positional shifts.

Coating head positioning errors: Low-resolution encoders/grating rulers or sensor feedback drift result in deviations between actual and preset coating positions.

Tension fluctuations: Unstable unwinding/winding tension causes substrate stretching or wrinkling, reducing coating precision.

2. Substrate (Foil) Issues

Non-uniform ductility: Inconsistent foil plasticity complicates gap control during coating.

Poor surface quality: Residual oxide layers weaken slurry adhesion, leading to partial coating or misalignment.

3. Slurry Properties

High viscosity impairing leveling: Poor slurry flowability causes uneven accumulation.

Large surface tension differences: Uneven edge shrinkage due to tension disparities between front/back coatings.

4. Process Settings

Inconsistent coating speeds: Speed differences between sides disrupt slurry spreading.

Drying condition variations: Temperature differences induce uneven thermal shrinkage, causing misalignment.

Ⅱ. Proposed Solutions

1. Equipment Precision Optimization

Regularly inspect roll coaxiality/flatness to control installation errors.

Upgrade coating head positioning components (e.g., high-resolution encoders) to limit deviations within ±0.1 mm.

Implement closed-loop tension control (e.g., PID adjustment) to maintain tension fluctuations below ±3%.

2. Substrate Consistency Control

Select high-uniformity copper/aluminum foils with stable elongation properties.

Adopt advanced surface treatments (e.g., low-temperature plasma cleaning) to enhance slurry adhesion uniformity.

3. Slurry Performance Adjustment

Optimize viscosity (anode: 10–12 Pa·s; cathode: 4–5 Pa·s) for better leveling.

Add surfactants (e.g., PVP, SDS) to balance surface tension between sides.

4. Process Parameter Refinement

Maintain identical coating speeds for both sides (error <0.5 m/min).

Apply segmented temperature control: Low-temperature pre-drying for stress relief and high-temperature curing, with overall temperature differences <5°C.

Ⅲ. Diagnosis and Monitoring Mechanisms

1. Equipment Diagnosis

Use laser interferometers to verify roll parallelism (error <0.02 mm/m).

Inspect motor/sensor signal stability to prevent drift exceeding 0.5% of the range.

2. Substrate Evaluation

Test elongation at break (deviation <±5%).

Analyze surface microstructure/oxide layers via SEM (thickness <50 nm).

3. Slurry Testing

Measure viscosity and thixotropy via rheometers (thixotropic area difference <5%).

Ensure surface tension difference <2 mN/m using tensiometers.

4. On-Line Process Control

Monitor coating thickness with laser sensors (CV <1%).

Post-drying X-ray inspection for coating density uniformity (lateral deviation <2%).

Conclusion

Through precise equipment calibration, material screening, slurry optimization, and systematic process management, A/B-side misalignment can be controlled within ≤0.5 mm. This effectively enhances battery consistency, safety, and cycle life.

At TOB NEW ENERGY, we are committed to being your strategic partner in advancing energy storage technologies. We empower next-generation lithium battery production through precision battery coating systems, intelligent battery production lines, and high-performance materials.  Our offerings extend to cutting-edge battery manufacturing equipment and battery tester, ensuring seamless integration across every stage of battery production. With a focus on quality, sustainability, and collaborative innovation, we deliver solutions that adapt to evolving industry demands. Whether you’re optimizing existing designs or pioneering next-generation batteries, our team is here to support your goals with technical expertise and responsive service.