LR1130 battery.Preparation and process flow of 18650 lithium-ion battery

(1) Ingredients


Positive electrode: Put a proportion of polyvinylidene fluoride (PVDF) and nitrogen methylpyrrolidone (NMP) into the stirrer.


Mix in a mixer and adjust the mixer speed; then add the positive active material and carbon black, vacuum and adjust
Low temperature lithium iron phosphate battery 3.2V 20A -20℃ charging, -40℃ 3C discharge capacity ≥70%

Charging temperature: -20~45℃ -Discharge temperature: -40~+55℃ -40℃ Support maximum discharge rate: 3C -40℃ 3C discharge capacity retention rate ≥70%
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full mixer speed.


Negative electrode: Put the latex and water into the mixer in proportion to mix, adjust the mixer speed to; then


Add CMS, vacuum, and adjust mixer speed.


(2) Coating


Place the aluminum strip (the negative is the copper strip) straightly on the coating machine, and ensure that the aluminum strip is not deflected, wrinkled,
Low temperature and high energy density 18650 3350mAh-40℃ 0.5C discharge capacity ≥60%

Charging temperature: 0~45℃ Discharge temperature: -40~+55℃ Specific energy: 240Wh/kg -40℃ Discharge capacity retention rate: 0.5C Discharge capacity ≥ 60%
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The belt travels smoothly, without material leakage or slipping. Apply the prepared slurry evenly on the machine and set the corresponding parameters.


These include the positive electrode pulping speed, negative electrode pulping speed, oven temperature, and coating width. During the transport process, it is necessary to


Observe whether the slurry is straight, without tilt or misalignment, and whether the thickness of the slurry applied to the aluminum strip (copper strip) is uniform and


consistent.


(3) Vacuum drying


Place the coated positive and negative electrodes in a vacuum oven for drying, with a vacuum degree of -0.09MPa.


(4) Cut large pieces


Cut the coated positive electrode sheet into large pieces of a certain length (according to the specific battery design), and use a shearing machine


The walking speed is 55mm/min, and the incision is required to be burr-free.


(6) Squeegee


Scrape off the slurry on one end of the positive and negative electrode sheets to prepare for ultrasonic spot welding. Use a double-sided scraper.


(7) Rolling


Press the strip-shaped pole pieces into pole pieces of a certain thickness for winding. Strictly control the thickness of the pole pieces during pressing and rolling.


The head-to-tail deviation of the rear pole piece shall not be greater than 0.010mm. Also keep the tablet press clean and clean it with alcohol every 2 hours


One-time tablet press.


(8) Cut into small slices


Cut the cut large pieces into small strips of a certain width (depending on the specific battery design).


The mouth has no burrs.


(1) Welding tab


Use an ultrasonic welding machine to weld the positive electrode tab (aluminum bar) and negative electrode tab (nickel bar) to the positive and negative electrode pieces respectively.


the wiper position. Pay attention to prevent welding deviation, welding misalignment, and false welding.


(2) Winding


Place the ion exchange membrane flushly on the winding needle, with the front end extending out of the winding needle 2-5mm, and the four corners of the pole piece are not


There may be wrinkles, the pole piece cannot fall off, the tape is applied at an angle, the single-sided tape is too long, the double-sided tape is misaligned, and the tape is


Defects such as solder joints are not covered. The positive electrode material must hug the negative electrode material. The pole piece must not be rolled sideways. The front end of the pole piece must be


It must be inserted to the top.


Check the winding defects: the ion exchange membrane is uneven, that is, the positive and negative electrodes exceed the exchange membrane; the sheet is high and the sheet is low; the pole sheet is not


Put it in place, the positive end of the outer ring does not hug the negative end, and the positive and negative plates of the inner ring are not connected to the top of the exchange membrane.


Overlapping, there is still a distance; the exchange membrane holds the negative pole piece too tightly; the positive aluminum strip and the negative nickel strip are too long and short;


The adhesive tape at the end of the cell core is poor; the battery core is not rolled in place: the distance between the positive and negative ears is too wide or narrow; the exchange membrane is not flattened


Wrinkled; the positive electrode is curled; the corners of the positive electrode are not curled or missing; the exchange membrane does not fully embrace the tail of the negative electrode; the inner and outer electrodes are


The piece is misaligned.


(3) Bottom welding


First put the insulating gasket into the steel case, then put the wound battery core into the steel case, and use a spot welder to connect the negative electrode ear.


Welded to the bottom of the steel shell. Check the outer surface of the bottom of the steel shell and pick out any appearance defects such as yellow spots, black spots, defects, explosions, etc.


And try to pull the tabs to find batteries with weak spot welds such as fire, weak soldering, and desoldering.


(4)Sealing


First use a spot welder to spot weld the steel shell and cap of the battery, and then use a laser welder to continuously laser weld


catch. Laser welding should ensure accurate positioning and clean parts to be welded. It is strictly forbidden to cause deformation or damage to the battery. Post-weld inspection


Check and repair welding on defective batteries with welding holes, explosions, etc.


(5) Baking


Bake for 12 hours at a constant temperature and vacuum of -0.09MPa. The main purpose is to dry out the battery cells.


of moisture.


(6) Injection


Inject the electrolyte into the vacuum-baked battery core in a glove box filled with Ar gas. The amount of liquid injected depends on the battery.


Depending on the design, the battery must be weighed before and after filling. The difference in weight is the amount of liquid injected, which can be used to determine the amount of liquid injected.


Whether the amount is appropriate or not.

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