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Battery Coating Process 25 Common Faults And Solutions

The factors affecting coating uniformity in the horizontal and vertical directions are different, so the control measures are also different accordingly. In the specific implementation, it is related to the design and manufacture of the machine, as well as the operation and process control. So what are the common faults that affect the coating process?

There are many factors that affect the coating quality, including people, machines, materials, methods, and environment, but the basic factors are several conditions directly related to the coating process: coating substrate, adhesive, coating steel roller/rubber roller and laminating machine, etc.

1) Coating substrate: mainly material, surface characteristics, thickness and uniformity, etc.

2) Adhesive: mainly its working viscosity, affinity and adhesion to the substrate surface, etc.

3) Coating steel roller: It is both the direct carrier of the adhesive and the support base of the coating substrate and rubber roller, so it is the core of the entire coating mechanism. Its geometric tolerance, rigidity, dynamic and static balance quality, surface quality, temperature uniformity and thermal deformation conditions all affect the uniformity of coating.

4) Coating rubber roller: The rubber roller refers to an important variable of coating quality. Its material (such as rubber layer life), hardness, shape and position tolerance, rigidity, dynamic and static balance quality, surface quality, thermal deformation condition, etc. also affect the uniformity of coating.

5) Laminating machine: It is the basic platform for coating. In addition to the accuracy and sensitivity of the coating steel roller and the rubber roller pressing mechanism, it also includes the maximum design speed and the overall stability of the machine.

The factors affecting coating uniformity in the horizontal and vertical directions are different, so the control measures are also different accordingly. In the specific implementation, it is related to the design and manufacture of the machine, as well as the operation and process control. So what are the common faults that affect the coating process?

Fault: Unwinding correction limit

Reason: Unwinding mechanism is not in center mode when threading

Solution: Adjust sensor position or adjust roll position in center position

Fault: Upper and lower limit fault of discharge floating roller

Reason: Discharge pressure roller is not pressed or winding tension is not open, potentiometer is abnormal

Solution: Press discharge pressure roller or open winding tension switch, recalibrate potentiometer

Fault: Traveling correction limit

Reason: Traveling correction is not centered or probe is abnormal

Solution: Re-center setting, check probe position and whether probe is damaged

Fault: Rewinding correction limit

Reason: Rewinding mechanism is not in center mode when threading

Solution: Adjust sensor position or adjust roll position in center position

Fault: Back roller has no opening and closing action

Reason: Back roller has not completed origin calibration or calibration sensor status is abnormal

Solution: Recalibrate origin or check whether origin sensor status and signal are abnormal

Fault: Back roller servo fault

Reason: Communication abnormality or loose wiring

Solution: Press the reset button to reset the fault or power on again, check the alarm code and query the manual

Fault: Intermittent coating on the second side

Reason: Fiber failure

Solution: Check whether the coating parameters or fiber signal are abnormal

Fault: Scraper servo failure

Reason: Alarm of the servo driver for adjusting the blade or abnormal sensor status, emergency stop of the equipment

Solution: Check the emergency stop button or press the reset button to eliminate the alarm, recalibrate the origin of the scraper roller and check whether the sensor status is abnormal

Fault: Scratches

Reason: Slurry particles or notched scraper

Solution: Clear particles with a feeler gauge and check the scraper

Fault: Powder loss

Reason: a. Powder loss caused by over-baking; b. High humidity in the workshop and water absorption of the electrode; c. Poor adhesion of the slurry; d. The slurry has not been stirred for a long time

Solution: Contact on-site quality technology

Fault: Insufficient surface density

Reason: a. Large height difference of the liquid level; b. Speed c. Blade

Solution: Check speed, blade parameters, and maintain a certain liquid level

Fault: Too many particles

Reason: a. Carried or precipitated by the slurry itself; b. Caused by the roller during single-sided coating; c. The slurry has not been stirred for a long time (static state)

Solution: Wipe the roller clean before coating. If the slurry has not been used for a long time, you need to consult the quality technology whether to stir it

Fault: Tailing

Reason: Slurry tailing, non-parallel gap between back roller or coating roller, back roller bounce speed

Solution: Adjust the gap parameter of inter-coating, increase the back roller bounce speed

Fault: Front misalignment

Reason: Alignment parameters are not corrected when there is an alignment error

Solution: Check whether the foil is slipping, clean the back roller, press the reference roller and press the roller, and correct the alignment parameters

Fault: The inter-coating on the back is parallel and tailing

Reason: The spacing between the coating back rollers is too small, too small, or the back roller bounce distance is too small

Solution: Adjust the spacing between the coating back rollers Increase the back roller bounce distance

Fault: Thick head and thin tail

Reason: Head and tail thinning parameters are not adjusted properly

Solution: Adjust the head and tail speed ratio and the head and tail starting point distance

Fault: Changes in coating length and intermittent process

Reason: There is slurry on the back roller surface, the traction rubber roller is not pressed, and the gap between the back roller and the coating roller is too small and too tight

Solution: Clean the back roller surface, adjust the inter-coating parameters, press the traction and rubber roller

Fault: Obvious cracks on the pole piece

Reason: Drying speed is too fast, oven temperature is too high, baking time is too long

Solution: Check whether the relevant coating parameters meet the process requirements

Fault: The pole piece is wrinkled during operation

Reason:

1. Parallelism between rollers;

2. Severe slurry or water on the surface of back roller and roller;

3. Poor joint of foil strip leads to unbalanced tension on both sides;

4. Abnormal deviation correction system or deviation correction is not turned on;

5. Too large or too small tension;

6. Inconsistent gap between back roller and travel;

7. Periodic elastic deformation of rubber surface of back roller after long-term use

Solution:

1. Adjust the parallelism of roller;

2. Deal with foreign matter between back roller and roller in time;

3. Adjust the tension adjustment roller of the machine head first, and adjust it to the original state after the foil is stable;

5. Check the tension setting value, the rotation of each transmission roller and the retracting roller to see if it is flexible , deal with the inflexible roller in time;

6. Expand the gap appropriately, and then slowly reduce it to the appropriate position;

7. When the elastic deformation is serious, replace the new rubber roller

Fault: edge bulging

Reason: The baffle board foam blocks it

Solution: When installing the baffle board, it can be in an outward eight shape or when moving the baffle board, it can be moved from the outside to the inside

Fault: Leakage

Reason: The baffle board foam or scraper board is not installed tightly

Solution: The scraper board gap is slightly larger than the layer thickness by 10-20 microns, and the baffle board foam is pressed tightly

Fault: Uneven winding

Reason: The winding shaft is not installed properly, not inflated, the deviation correction is not turned on, or the winding tension is not turned on

Solution: Install and fix the reel, inflate the air shaft, turn on the correction function, reel tension, etc.

Fault: Uneven white space on both sides

Reason: The installation position of the baffle plate, the unwinding correction is not turned on

Solution: Move the baffle plate, check the rewinding correction

Fault: The reverse side intercoating cannot be tracked

Reason: No sensing input of the optical fiber or no intercoating on the front

Solution: Check the detection distance of the optical fiber head, optical fiber parameters, and the coating effect on the front

Fault: Correction does not work

Reason: The optical fiber parameters are incorrect, the correction switch is not turned on

Solution: Check whether the optical fiber parameters are reasonable (whether the correction indicator light flashes left and right), and whether the correction switch is turned on.

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