20L Lithium-Ion Battery Slurry Dual-Planetary Mixer Repair Case Study – Wuxi Customer
Customer Information
| Item | Details |
|---|---|
| Customer Location | Wuxi, Jiangsu Province |
| Equipment Model | 20L Lithium-Ion Battery Slurry Dual-Planetary Mixer |
| Delivery Date | 2024 |
| Return Date | August 2026 |
| Application | Cathode and anode slurry production for lithium-ion batteries |
Background
A Wuxi-based lithium battery material manufacturer purchased a 20L dual-planetary mixer from us in 2024. The equipment is primarily used for high-viscosity mixing and dispersion of cathode and anode slurries in lithium-ion battery production. With its unique planetary motion combining revolution and rotation, the mixer effectively handles slurry systems with solid content as high as 3,000,000 cps, making it a critical piece of equipment on the customer's production line.
After more than two years of continuous operation, the customer reported several issues including insufficient vacuum level, abnormal operating noise, and oil leakage, which were affecting normal production. Upon receiving the feedback, we responded promptly and arranged for the equipment to be returned to our facility for comprehensive inspection and repair.
Fault Symptoms
Upon arrival, our technical team conducted a systematic inspection and confirmed the following major issues:
Vacuum system failure: After starting the vacuum pump, the system pressure could not reach the target value of -0.095MPa within 3 minutes. The pressure drop exceeded 0.005MPa during a 30-minute hold test, failing to meet the degassing process requirements for slurry production.
Abnormal mixing noise: Intermittent metallic knocking sounds were heard from the mixing impeller area during operation, indicating a potential risk of impeller-to-wall contact.
Bearing seal leakage: Obvious oil stains were found around the planetary gearbox bearing area, contaminating the equipment surface and working environment.
Fault Diagnosis and Analysis
After step-by-step troubleshooting, our technical team reached the following conclusions:
Vacuum system: The O-ring seal on the tank lid had experienced compression set due to prolonged exposure to organic solvents in the slurry, resulting in loss of elasticity. This was the primary cause of the vacuum failure. Additionally, the mechanical seal on the mixing shaft had exceeded its recommended replacement interval (every 24 months or 3,000 operating hours). The worn sealing faces further contributed to vacuum leakage.
Abnormal mixing noise: Precise measurements revealed that the clearance between the impeller outer edge and the tank wall had exceeded the standard range (standard clearance should be 1.5%-2% of the tank diameter). The root cause was identified as impeller wear and loosening of positioning components over extended operation, leading to reduced clearance and interference between the impeller and tank wall.
Bearing oil leakage: The bearing seals had aged and lost their sealing function. Combined with excessive lubricant application, this resulted in oil seeping out from the bearing housing.
Repair Solutions
Targeted repair measures were implemented for each fault, as summarized in the table below:
| Fault Symptom | Root Cause | Solution |
|---|---|---|
| Vacuum level cannot reach target | O-ring aged and deformed; mechanical seal worn beyond limit | Replace with FKM O-ring; replace complete mechanical seal assembly (rotary face + stationary face + sealing ring) |
| Abnormal mixing noise | Impeller wear and positioning looseness causing clearance deviation | Realign impeller and tank body; replace worn impeller; adjust clearance to standard range |
| Bearing oil leakage | Seal aging; excessive lubricant application | Replace bearing seals; refill lubricant to standard quantity; clean oil residue |
During the repair process, our technicians also identified a minor leak at the hydraulic station oil pipe fitting, which was promptly tightened to eliminate any potential hidden hazard.
Post-Repair Test Results
After completing all repairs, the equipment underwent a 72-hour continuous trial run with actual slurry materials. The test results are summarized below:
| Test Item | Standard Requirement | Measured Result | Status |
|---|---|---|---|
| Ultimate vacuum level | ≤ -0.095MPa | -0.098MPa | Pass |
| Pressure drop over 30 min hold | ≤ 0.005MPa | ＜ 0.005MPa | Pass |
| Operating noise | No abnormal sound | Normal | Pass |
| Bearing seal integrity | No leakage | No leakage | Pass |
All performance indicators have been restored to factory specifications, fully meeting normal production requirements.
Recommendations for the Customer
To extend equipment service life and ensure production continuity, we recommend the following daily maintenance practices:
Regular seal inspection: Check the lid O-ring for deformation, hardening, or damage before each startup. Replace immediately if any abnormality is found.
Proper lubricant management: Strictly follow the quantity specified in the operation manual. Over-lubrication can be just as harmful as under-lubrication.
Periodic clearance verification: Inspect the impeller-to-wall clearance once every quarter to ensure it remains within the standard range.
Vacuum pump maintenance: Replace vacuum pump oil regularly (recommended every 500 hours or annually) and clean the inlet filter periodically.
Maintain maintenance records: Keep a log of all maintenance activities, including dates, tasks performed, and parts replaced, to facilitate tracking and preventive maintenance planning.
The dual-planetary mixer is the core equipment in lithium-ion battery slurry preparation. Its vacuum sealing performance and mixing precision directly affect slurry dispersion quality and final battery performance. This repair case once again highlights the importance of regular preventive maintenance. Replacing critical components before they reach the end of their service life can effectively avoid unplanned downtime and production losses.
Our company is committed to providing full-lifecycle services, from equipment selection and installation to after-sales support. Should you encounter any issues during operation, please do not hesitate to contact our after-sales service team.
With over 20 years of experience in R&D and manufacturing of mixing equipment, we offer a complete range of models from laboratory-scale to mass-production lines. Welcome to contact us for more information.
