18650 cylindrical battery: It is a secondary battery (rechargeable battery), which mainly relies on lithium ions to move between the positive and negative electrodes to work. During the charge and discharge process, Li + is intercalated and deintercalated between the two electrodes: during charging, Li + is deintercalated from the positive electrode and inserted into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge.
18650 Cylindrical Battery
2000mAh Li-ion battery manufacturer share for you:
Lithium-based batteries are divided into lithium batteries and lithium-ion batteries. Both mobile phones and laptops use lithium-ion batteries, which are commonly referred to as lithium batteries. The battery generally uses a material containing lithium as an electrode, which is a representative of modern high-performance batteries.
Lithium-ion batteries are easily confused with the following two types of batteries:
(1) Lithium battery: Metal lithium is used as the negative electrode.
(2) Lithium-ion battery: use non-aqueous liquid organic electrolyte.
(3) Lithium-ion polymer battery: use polymer to gelate liquid organic solvent, or directly use all solid electrolyte. Lithium-ion batteries generally use graphite-based carbon materials as the negative electrode.
According to different electrolyte materials used in lithium-ion batteries, lithium-ion batteries are divided into liquid lithium-ion batteries and polymer lithium-ion batteries (PLB).
18650 rechargeable lithium battery is currently the most widely used battery in modern digital products such as mobile phones, notebook computers, but it is more "delicate", in use must not be overcharged, overcharged (will damage the battery Of its scrap). Therefore, there are protection components or protection circuits on the battery to prevent expensive battery damage. Lithium-ion battery charging has high requirements. To ensure the termination voltage accuracy within ± 1%, major semiconductor device manufacturers have developed a variety of lithium-ion battery charging ICs to ensure safe, reliable and fast charging.
Mobile phones basically use lithium-ion batteries. Proper use of lithium-ion batteries is important to extend battery life. According to the requirements of different electronic products, it can be made into flat rectangular, cylindrical, rectangular and button type, and has a battery pack composed of several batteries connected in series and parallel. The rated voltage of a lithium-ion battery is generally 3.7V due to changes in materials, and the lithium iron phosphate (hereinafter referred to as iron phosphate) positive electrode is 3.2V. When fully charged, the termination charging voltage is generally 4.2V, and iron phosphate is 3.65V. The termination discharge voltage of a lithium-ion battery is 2.75V to 3.0V (the battery factory gives the working voltage range or the termination discharge voltage. The parameters are slightly different, generally 3.0V and 2.5V for ferrophosphorus). Continuous discharge below 2.5V (ferrous phosphate 2.0V) is called overdischarge, and overdischarge will damage the battery.
Lithium-ion batteries with lithium cobaltate type as the positive electrode are not suitable for high-current discharge, and the discharge time will be reduced when the high-current discharge occurs (high temperature will be generated inside and energy is lost), and may be dangerous; The cathode material lithium battery can be charged and discharged with a large current of 20C or more (C is the capacity of the battery, such as C = 800mAh, 1C charge rate is 800mA), which is especially suitable for electric vehicles. Therefore, the battery production factory gives the maximum discharge current, which should be less than the maximum discharge current in use. Lithium-ion batteries have certain requirements for temperature. The factory gives the charging temperature range, discharge temperature range and storage temperature range. Over-voltage charging will cause permanent damage to the lithium-ion battery. The lithium-ion battery charging current should be in accordance with the recommendations of the battery manufacturer and require a limited current circuit to avoid overcurrent (overheating). The commonly used charging rate is 0.25C ~ 1C. During high current charging, the battery temperature is often detected to prevent overheating from damaging the battery or generating an explosion.
Lithium-ion battery charging is divided into two stages: constant current charging first, and then changing to constant voltage charging when the termination voltage is approached. For example, a 800mAh battery has a termination charge voltage of 4.2V. The battery is charged at a constant current of 800mA (the charge rate is 1C). At the beginning, the battery voltage is boosted with a large slope. When the battery voltage is close to 4.2V, it is changed to 4.2V constant voltage charging. The current gradually decreases and the voltage does not change much. When the charging current drops to 1 / 10-50C (the factory settings are different, it does not affect the use), it is considered to be close to full, and the charging can be terminated (some chargers start the timer after 1 / 10C, after a certain period of time End charging).