What are the advantages and disadvantages of lithium batteries

Type 18650 lithium battery is a lithium battery commonly used in electronic products. It is also one of the most important battery types in the current charging battery. Generally, it is cylindrical, with a diameter of 18 mm and a height of 65.0 mm. So what are the pros and cons of the 18650 cell? Advantages: 1. Wide application: the battery charger, laptop, intercom, portable DVD, instruments, audio equipment, model aircraft, toys, cameras, digital cameras, and other electronic equipment are used. 2. Flexible combination: in parallel and in series, 18650 cells with different Numbers can easily make a variety of battery packs through the conventional combination to meet different needs. 3, small internal resistance, 18650 batteries internal resistance under 35 m Ω commonly, greatly reduced since the power consumption of the battery, prolong the duration of the battery. 4. No memory effect: the 18650 battery is a lithium-ion battery with no memory effect. 5. High voltage: the voltage of 8650 lithium battery is generally 3.6v, 3.8v and 4.2v, which is much higher than the 1.2v voltage of NiCd and NiMH batteries. 6, high safety: 18650 batteries will be a qualified safety inspection by the following: (1) short circuit: no fire, no explosion (2) charge: no fire, no explosion (3) the hot box test: no fire, no explosion (150 ℃ temperature 10 min) (4) needle thorn: not the explosion (with 3 mm Ф penetrate cells) (5) tablet: no fire, no explosion (10 kg weight from 1 m high hit to battery) (6) burning: no explosion (gas flame barbecue battery) 7, long service life: charge-discharge cycles is more than 500 times. 8. High capacity: the capacity is usually 1200mah-3000mah, and the common capacity is 2200mah-2600mah. 9. Low price: for polymer cells, the price of 18650 cells is much lower. Cons - 1, aging: all lithium-ion batteries slowly lose capacity, depending on the number of USES and temperature. 2. Difficult to recycle: almost none are recycled. 3. Intolerance of overcharge and over discharge: when overcharge occurs, excessive embedded lithium ions will be permanently fixed in the lattice and cannot be released again, resulting in relatively short battery life. When too much lithium ions are released from the electrode during over discharge, lattice collapse can be caused, thus shortening the lifetime. 4, not flexible: due to the basic shape and size has been fixed, so it is difficult to have polymer cell as flexible, of course, this is also an advantage, specification is fixed means replaceable. In general, the 18650 cell has enough advantages that it won't be phased out until new battery technologies are developed.

18650 is the ancestor of lithium-ion battery -- a standard lithium-ion battery model set by SONY of Japan in order to save costs. Among them, 18 indicates the diameter of 18mm, 65 indicates the length of 65mm, and 0 indicates the cylindrical battery.

The common 18650 battery is divided into lithium ion battery and lithium iron phosphate battery. The nominal voltage of the lithium-ion battery is 3.7v, the cut-off voltage of charge is 4.2v, the nominal voltage of lithium iron phosphate battery is 3.2v, the cut-off voltage of charge is 3.6v, the capacity is usually 1200mah-3350mah, the common capacity is 2200mah-2600mah.

Lithium battery (Li-ion, LithiumIonBattery) : lithium ion battery has a lightweight, large capacity, no memory effect, etc, thus obtained

18650 lithium batteries

18650 lithium batteries

Widespread - many digital devices use lithium-ion batteries for power, although they are relatively expensive. The energy density of the lithium-ion battery is very high, its capacity is 1.5~2 times of the weight of nickel metal hydride battery, and has a very low self-discharge rate. In addition, lithium-ion battery almost no "memory effect" and does not contain toxic substances and other advantages is also an important reason for its wide application. Also please note that the lithium battery external generally marked with English 4.2 V lithium-ion battery V lithium secondary battery (lithium battery) or 4.2 (lithium secondary battery), 4.2 V lithium ion rechargeable battery (rechargeable lithium battery), so the user must see when buying batteries battery block appearance, prevent because they didn't see the battery type and cadmium-nickel, nickel-metal hydride batteries will be mistaken for lithium batteries.

Lithium battery standard 3.7v or 4.2v is the same. Just what manufacturer label is different and oneself. 3.7v refers to the platform voltage (i.e., the typical voltage) that the battery discharges during use, while 4.2v refers to the voltage at which the battery is fully charged. Common 18650 rechargeable lithium battery, the voltage is 3.6 or 3.7 v, the charge is 4.2 v, this has very little to do with power (capacity), 18650 battery capacity of mainstream mah from 1800 to 2600 mah, (more than 18650 power battery capacity in 2200 ~ 2600 mah), the capacity of the mainstream and even more than the 3500 or 4000 mah has (remind everybody, above the nominal 3350 mah on the market of domestic batteries are likely to false, the current domestic production of the maximum capacity is 3350 mah.).

Generally, the no-load voltage of lithium battery is considered to be used up when it is below 3.0v (the specific value depends on the threshold value of the battery protection board, such as low as 2.8v or 3.2v). Most lithium batteries cannot discharge the no-load voltage below 3.2v, or excessive discharge will damage the battery (generally, lithium batteries in the market are basically used with a protective plate, so excessive discharge will lead to the protection plate cannot detect the battery, thus unable to charge the battery). 4.2v is the maximum limiting voltage for battery charging, and it is generally believed that charging the no-load voltage of lithium battery to 4.2v means that the battery is fully charged. In the process of battery charging, the battery voltage gradually rises from 3.7v to 4.2v. Lithium battery charging cannot charge the no-load voltage to more than 4.2v, or it will damage the battery.

The 18650 battery life theory gives 1,000 cycles of charge. Due to the unit density of the capacity is very large, so most of the notebook computer batteries, except

18650 lithium batteries

18650 lithium batteries

In addition, because 18650 has very good stability in work, it is widely used in various major electronic fields: it is often used in high-grade strong light flashlight, portable power supply, wireless data transmission device, electric heating clothes, shoes, portable instruments and meters, portable lighting equipment, portable printers, industrial instruments, medical instruments and so on.

18650 means 18mm in diameter and 65mm in length. Model number 5 is 14500, with a diameter of 14mm and a length of 50mm. Generally 18650 batteries in the industrial use more, less civil, common also in the notebook battery and high-end flashlight use more.

The 18650 is only the size and model of the battery. According to the battery type, it can be divided into 18650 for lithium ion, 18650 for lithium iron phosphate, 18650 for nickel hydrogen (very rare), and the common 18650 for a lithium ion.

Charging and discharging principle

The working principle of the lithium-ion battery is its charge and discharge principle. When you charge the battery, you have lithium ions forming on the positive side of the battery, lithium forming

18650 lithium batteries

18650 lithium batteries

Ions travel through the electrolyte to the negative electrode. As the carbon of the negative electrode is layered, it has many micropores. The lithium ions that reach the negative electrode are embedded into the micropores of the carbon layer. The more lithium ions embedded, the higher the charging capacity.

Similarly, when a battery is discharged (the process by which we use the battery), lithium ions embedded in the negative carbon layer escape and move back to the positive electrode. The more lithium ions that return to the positive electrode, the higher the discharge capacity. We usually say the battery capacity refers to the discharge capacity.

It is not difficult to see that during the charging and discharging process of the lithium-ion battery, lithium ion is in the motion state from the positive pole to the negative pole to positive pole. If we think of the lithium-ion battery as a rocking chair, the two ends of the rocking chair are the two poles of the battery, and the lithium ion is like a good athlete, running back and forth between the two ends of the rocking chair. So, the experts gave the lithium-ion battery a cute name: the rocking chair battery.

Charging and discharging process

The lithium battery charging control is divided into two stages. The first stage is a constant current charging. When the battery voltage is lower than 4.2v, the charger will charge at a constant current. The second stage is the constant voltage charging stage, when the battery voltage is 4.2 V, due to the lithium battery characteristics, if the voltage is high, will damage, the charger voltage will be fixed in 4.2 V, the charging current will be reduced gradually, when the current decreases to a certain value (usually 1/10 set current), to cut off the charging circuit, a complete charging indicator, charging is complete.

Excessive charge and discharge of lithium-ion battery will cause permanent damage to the positive and negative electrodes. The excessive discharge will lead to the collapse of the structure of the negative carbon sheet, which will lead to the collapse

18650 lithium battery charger

18650 lithium battery charger

Lithium ions cannot be inserted during charging. Overcharging causes too many lithium ions to embed themselves in the negative carbon structure, so that some of them can no longer be released.

Some chargers use cheap solutions to achieve, in the control accuracy is not good enough, easy to cause abnormal battery charging, or even damage the battery. When choosing a charger, try to choose a big brand of 18650 lithium ion battery charger, the quality, and after-sales guarantee, to extend the service life of the battery. The 18650 lithium-ion battery charger guaranteed by the brand has four protection functions: short circuit protection, over current protection, over voltage protection and battery reverse connection protection. Overcharge protection: when the charger overcharges the lithium-ion battery, the charging state shall be terminated to prevent the rise of internal pressure caused by temperature rise. To this end, the protection device needs to monitor the battery voltage, and when it reaches the battery overcharge voltage, it will activate the overcharge protection function and stop charging. Over-discharge protection: in order to prevent the over-discharge state of lithium ion battery, when the voltage of lithium-ion battery is lower than the detection point of its over-discharge voltage, the over discharge protection will be activated and the discharge will be stopped, and the battery will be kept in the standby mode of low static current. Over current and short circuit protection: when the discharge current of lithium-ion battery is too large or short circuit occurs, the protective device will activate the overcurrent protection function.

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