Preparation of electrode sheets
(1) Ingredients
Positive electrode: A mixture of polyvinylidene fluoride (PVDF) and N-methylpyrrolidone (NMP) in a certain proportion is added to a stirring pan.
Mix the materials in a mixer, adjusting the mixer speed; then add the positive electrode active material and carbon black, create a vacuum, and adjust...
Adjust the mixer speed.
Negative electrode: Mix latex and water in a mixer according to the specified ratio, adjusting the mixer speed to [speed value missing]; then...
Add CMS, create a vacuum, and adjust the mixer speed.
(2) Coating
Place the aluminum strip (with copper strip as the negative electrode) flat on the coating machine, ensuring that the aluminum strip is not misaligned or wrinkled.
Smooth conveyor belt movement, no material leakage, and no slippage. Apply the prepared slurry evenly to the machine, set the appropriate parameters, and...
These include the positive electrode feed rate, the negative electrode feed rate, the oven temperature, and the coating width. During the conveyor belt operation, it is necessary to...
Observe whether the slurry is straight, without tilting or misalignment, and whether the thickness of the slurry applied to the aluminum (copper) strip is uniform.
Consistent.
(3) Vacuum drying
The coated positive and negative electrodes were placed in a vacuum oven for drying, with a vacuum degree of -0.09 MPa.
(4) Cut large pieces
The coated positive electrode sheet is cut into large pieces of a certain length (depending on the specific battery design) using a shearing machine.
The running speed is 55 mm/min, and the cut should be burr-free.
(6) Scraper
Scrape off the slurry from one end of the positive and negative electrode plates to prepare for ultrasonic spot welding, scraping the plates on both sides.
(7) Roller pressing
The strip-shaped electrode sheets are pressed into sheets of a certain thickness for winding. The thickness of the electrode sheets is strictly controlled during pressing and rolling.
The deviation between the first and last ends of the rear electrode should not exceed 0.010 mm. At the same time, keep the tablet press clean and clean it with alcohol every 2 hours.
A single tablet press.
(8) Cut into small pieces
Cut the large slices into strips of a certain width (depending on the specific battery design). The cutting process should be precise.
The mouth is smooth and free of burrs.
(1) Welding electrode lug
The positive electrode tab (aluminum strip) and negative electrode tab (nickel strip) are welded to the positive and negative electrode sheets respectively using an ultrasonic welding machine.
The scraper position. Care should be taken to prevent welding misalignment, incorrect welding, and incomplete welding.
(2) Winding
Place the ion exchange membrane flat on the winding needle, with the front end extending 2-5mm beyond the needle. The four corners of the electrode should not be...
There should be wrinkles, the electrode sheet should not have any loose material, the adhesive tape should not be applied at an angle, the single-sided adhesive tape should not be too long, the double-sided adhesive tape should not be misaligned, and the adhesive tape should not be misaligned.
Defects such as uncovered solder joints must be addressed; the positive electrode material must fully grip the negative electrode material; the electrode sheet must not be rolled off-center; and the front end of the electrode sheet must be...
It must be inserted to the top.
Inspect for winding defects: uneven ion exchange membranes, i.e., positive and negative electrodes extending beyond the exchange membrane; electrodes too high or too low; electrodes not fully extended.
When placed in position, the outer ring positive electrode end did not grip the negative electrode end, and the inner ring positive and negative electrode plates were not in contact with the top of the exchange membrane.
Overlap, but still some distance; the exchange membrane is too tight around the negative electrode end; the positive electrode aluminum strip and the negative electrode nickel strip are too long or too short; the electrical...
Poorly applied adhesive tape at the end of the battery cell; battery cell not properly wound; gap between positive and negative tabs too wide or too narrow; exchange membrane not flattened.
Wrinkled; positive electrode edge rolled; positive electrode plate with unrolled or missing corners; exchange membrane not fully enclosing the negative electrode plate tail; inner and outer electrode layers
The image is misaligned.
(3) Bottom weld
First, place the insulating pad into the steel shell, then place the wound battery cell into the steel shell, and use a spot welding machine to attach the negative electrode tab.
Welded to the bottom of the steel shell. Inspect the outer surface of the bottom of the steel shell, and pick out any defects such as yellow spots, black spots, flaws, and splattering.
They also tested the electrode tabs and picked out batteries with poor spot welding, such as those that sparked, had cold solder joints, or detached from the solder joints.
(4) Seal
First, spot weld the steel casing and cap of the battery together using a spot welding machine, then use a laser welding machine for continuous laser welding.
Attachment. Laser welding must ensure accurate positioning and cleanliness of the welded area. Deformation or damage to the battery is strictly prohibited. Post-weld inspection is required.
Inspect and repair batteries with defects such as weld holes or sparks by welding.
(5) Baking
Baking for 12 hours under constant temperature and vacuum conditions of -0.09MPa is mainly to dry the battery cells.
The moisture content.
(6)Injection
After vacuum baking, the battery cells are filled with electrolyte in a glove box filled with Ar gas. The amount of electrolyte injected depends on the battery's specific requirements.
Unlike other designs, the battery is weighed before and after electrolyte injection. The weight difference represents the amount of electrolyte injected, which is used to determine the amount of electrolyte injected.
Is the quantity appropriate?
