li ion 18650 battery pack price

　　Problems to be paid attention to in the winding process of 18650 lithium ion battery

　　1. Objective: To prevent water absorption during the winding process of the positive and negative electrodes, resulting in zero voltage, self-discharge, and poor cycle performance;

　　Method: Calculate the dew point value and temperature value to obtain the temperature and humidity value.

　　Low temperature lithium iron phosphate battery 3.2V 20A -20℃ charge, -40℃ 3C discharge capacity ≥70%

　　Charging temperature: -20~45℃ -Discharging temperature: -40~+55℃ -40℃ supports maximum discharge rate: 3C -40℃ 3C discharge capacity retention rate≥70%

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　　2. Dust control ≤ 100,000PC/ft3 (particle size 0.5um)

　　Purpose: To prevent dust in the pole group during the winding process, causing short circuit, overheating, fire, self-discharge and other phenomena.

　　Method: Dust analyzer was used.

　　3. Abnormal glitch reduction

　　Process requirements: pole piece ≤ 8um; pole ear burr ≤ 12um; Test method: 1 computer electric cell randomly selects the first one to check each machine at each transition, and the positive and negative electrodes of the front and rear ends of the burr cutting and the positive and negative electrodes of the ear Negative electrode according to the operation instruction of glitch detection.

　　Low temperature high energy density 18650 3350mAh-40℃ 0.5C discharge capacity ≥60%

　　Charging temperature: 0~45℃ Discharging temperature: -40~+55℃ Specific energy: 240Wh/kg -40℃ discharge capacity retention rate: 0.5C discharge capacity≥60%

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　　Adverse reactions: The plate or tab burr exceeds the technical requirements, which may lead to perforation of the diaphragm, short circuit of positive and negative electrodes, overheating of the battery, explosion in severe cases, and serious safety hazards.

　　18650 lithium ion battery winding steps

　　4. The anode and cathode plates are not well covered

　　Process requirements: The centering of the positive and negative plates is 0.75 to 55 mm.

　　Negative plate and separator aligned to 1?5 mm

　　Detection method: After changing the volume of sampling, observe the degree of adverse reaction after continuous 3 PCS batteries are calibrated by X-ray wi test: 1) - Process alignment out of specification may cause negative not including positive plate, during battery charging, make Lithium There is no corresponding graphite embedded in the front of the ion, and there is free accumulation on the dendrites of the cathode of the lithium-ion battery. The dendrites pierce the separator and cause an internal short circuit, which poses a safety hazard.

　　2) The alignment between the negative plate and the diaphragm exceeds the technical standard, which may cause the negative plate to be squeezed and deformed. Part of the negative electrode material on the electrode plate falls off, and the battery swells during charging.

　　5. Coverage test method difference (length of outer negative super positive material and inner negative super positive material) of winding pole piece direction: every 2h, each winding machine conducts sampling inspection of 3 pc core anatomy, and measures separately Both cover different dimensions with eyepieces and rulers.

　　Adverse reactions: The negative plate cannot cover the positive plate. During the charging process of the battery, after the lithium ions are separated from the positive electrode, no corresponding graphite can be found to embed them, resulting in the accumulation of free lithium ions in the battery on the negative electrode, and dendrites appear. The dendrites puncture the membrane, causing an internal short circuit and compromising safety.

　　18650 lithium ion battery winding steps

　　6. Short circuit test

　　Parameter setting (100V, 25nF250V,

　　Test method: The short-circuit sample testing machine should be used for the initial inspection of each shift; adverse effects: self-discharge, heat generation, explosion and other short-circuit factors: cutting particles, metal dust, burrs, etc., resulting in rupture of the diaphragm hole;

　　7. Glue foil and tab tension

　　Process requirements: Tensile strength > 15N bonding foil area > 2/3 welding printing

　　Test method: 1PCS battery is sampled every 2H for tensile test and foil test