Li-ion Rechargeable Battery

Li(NiCoMn)O2 lithium battery

Li(NiCoMn)O2 lithium-ion batteries: Lithium-ion batteries are widely used because of their advantages of light weight, large capacity and no memory effect. Many digital devices use lithium-ion batteries as power supply, although their prices are relatively expensive. Lithium-ion batteries have high energy density, 1.5-2 times the capacity of Ni-MH batteries of the same weight, and low self-discharge rate. In addition, lithium-ion batteries have few "memory effects" and no toxic substances, which are also important reasons for their wide application. In addition, please note that lithium batteries are usually marked 4.2V lithium ion battery (lithium battery) or 4.2V lithium secondary battery (lithium secondary battery) in English, and 4.2V lithium ion rechargeable battery (rechargeable lithium battery). Therefore, when purchasing batteries, users must be aware of the external signs of the batteries, so as to prevent the misconception of nickel-cadmium/ nickel-hydrogen batteries and Lithium batteries because of doing not see the type of batteries clearly.

 

Type distinction

The standard of Li(NiCoMn)O2 lithium batteries is 3.7V or 4.2V. It's just that the manufacturer labels it differently. 3.7V refers to the plateau voltage (i.e. typical voltage) discharged during the use of batteries, while 4.2V refers to the voltage at full charge. Common rechargeable lithium-ion batteries 14500 18500 18650 21700 26650 with voltage of 3.6 or 3.7V and full charge of 4.2v, which has little relationship with the capacity. The mainstream capacity of Li(NiCoMn)O2 lithium-ion batteries ranges from 800mAh to 5000mAh, (14500 battery capacity ranges from 600 to 800mAh, 18500 battery capacity ranges from 1200 to 1500mAh, 18650 battery capacity ranges from 2200mAh to 2600mAh, and 21700 battery capacity ranges from 2800 to 3400mAh. The capacity of 26650 batteries ranges from 3400mAh to 5000mAh.

 

It is generally believed that if the no-load voltage of lithium batteries is below 3.0V, the power will be exhausted (the specific value needs to see the threshold value of the battery protection panel, for example, as low as 2.8V and 3.2V). Most lithium batteries can not discharge the no-load voltage below 3.2V, otherwise excessive discharge will damage the battery (in general, the lithium batteries in the market are basically used with protective panels, so excessive discharge will also lead to the protection panels can not detect the battery, thus unable to charge the battery). 4.2V is the maximum limit voltage for battery charging. It is generally considered that charging the no-load voltage of lithium battery to 4.2V is full. During the charging process, the voltage of the battery gradually rises from 3.7V to 4.2V. Lithium battery charging can not charge the no-load voltage to more than 4.2V, otherwise it will damage the battery, which is the special place of lithium battery.

Usage

The life theory of Li(NiCoMn)O2 lithium batteries is 1000 cycles of charging. Because of the large capacity per unit density, most of them are used in laptop batteries. In addition, because of the excellent stability of lithium-ion batteries in work, they are widely used in various electronic fields: high-grade flashlight, portable power supply, wireless data transmitter, electric heating clothing, shoes, portable instruments, portable lighting equipment, portable printers. Industrial instruments, medical instruments, etc.

 

Charge discharge

Charging and Discharging Principle

The working principle of lithium ion batteries refers to their charging and discharging principles. When the battery is charged, lithium ions are generated on the positive electrode of the battery, and the lithium ions are moved to the negative electrode through the electrolyte. As a negative electrode, carbon has a layered structure. It has many micro-holes. The lithium ion that reaches the negative electrode is embedded in the micro-holes of the carbon layer. The more lithium ions are embedded, the higher the charge capacity is.

 

Likewise, when the battery is discharged (that is, the process of using the battery), the lithium ion embedded in the carbon layer of the negative electrode is released and moves back to the positive electrode. The more lithium ions returned to the cathode, the higher the discharge capacity. What we usually call battery capacity refers to is discharge capacity.

 

It is not difficult to see that in the process of charging and discharging lithium ion batteries, lithium ion is in the state of movement from positive to negative to positive. If we imagine lithium-ion batteries as a rocking chair, the two ends of the rocking chair are the two poles of the batteries, and the lithium ion is like a good athlete, running back and forth at both ends of the rocking chair. So experts gave lithium-ion batteries a lovely name, rocking-chair batteries.

 

Charging and discharging process

The charging control of lithium battery is divided into two stages. The first stage is constant current charging. When the battery voltage is less than 4.2V, the charger will charge with constant current. The second stage is the constant voltage charging stage. When the battery voltage reaches 4.2V, due to the characteristics of lithium battery, if the voltage is higher, it will be damaged. The charger will fix the voltage at 4.2V, and the charging current will gradually decrease. When the current is reduced to a certain value (generally when the current is set at 1/10), the charging circuit will be cut off, the charging indicator will be on and the charging will be completed.

 

Overcharging and discharging of lithium-ion batteries can cause permanent damage to positive and negative electrodes. Overdischarge leads to the collapse of the carbon sheet structure of the negative electrode, and the collapse will result in the insertion of lithium ions in the charging process.

 

Overcharging causes excessive lithium ions to be embedded in the carbon structure of the negative electrode, resulting in some lithium ions can no longer be released.

 

Some chargers are implemented by cheap schemes, which are not good enough in control accuracy, and are liable to cause abnormal battery charging and even damage the battery. When choosing a charger, try to choose a large brand of Li(NiCoMn)O2 lithium-ion battery charger. The quality and after-sale are guaranteed, and the service life of the battery is prolonged. Brand-guaranteed Li(NiCoMn)O2 lithium-ion battery charger has four protection functions: short circuit protection, over-current protection, over-voltage protection, battery reverse connection protection and so on. Overcharge protection: When the charger overcharges lithium-ion batteries, in order to prevent the internal pressure rise caused by temperature rise, it is necessary to terminate the charging state. Therefore, the protection device needs to monitor the battery voltage. When it reaches the battery overcharge voltage, it activates the overcharge protection function and stops charging.

 

Overdischarge protection: In order to prevent overdischarge of lithium-ion batteries, when the voltage of lithium-ion batteries is lower than its detection point of overdischarge voltage, the overdischarge protection is activated, the discharge is stopped, and the batteries are kept in the standby mode of low static current. Overcurrent and Short Circuit Protection: When the discharge current of lithium ion batteries is too large or short circuit occurs, the protection device will activate the overcurrent protection function.

 

General configuration

The nominal voltage of a single section is generally 3.6V or 3.7V.

 

Charging voltage is generally 4.20V (lithium cobalt oxide is 4.2V-4.3V)

 

The minimum discharge termination voltage is generally 2.75V. Lower than this voltage can easily lead to a serious decline in battery capacity and even scrap.

 

Maximum charging termination voltage: 4.20V

Diameter: 18 + 0.2mm

Height: 65 + 2.0mm

Advantages and disadvantages

Advantage

 

1. The capacity of large-capacity lithium-ion batteries is generally between 800 MAH and 5000 mah, while the capacity of general batteries is only about 600 mah. If combined into lithium-ion batteries, lithium-ion batteries can easily break through 10000 mah.


2. The service life of Li(NiCoMn)O2 lithium batteries is very long. The service life of Li(NiCoMn)O2 lithium batteries can reach more than 500 cycles in normal use, which is more than twice that of ordinary batteries.


3. High safety performance: Li(NiCoMn)O2 lithium battery has high safety performance, no explosion, no combustion; non-toxic, non-polluting, and has been certified by RoHS trademark; all kinds of safety performances are completed at one go, the cycle times are more than 500 times; high temperature resistance, discharge efficiency reaches 100% at 65 degrees. In order to prevent short circuit, the positive and negative electrodes of Li(NiCoMn)O2 lithium batteries are separated. So the possibility of short circuit has been reduced to the extreme. Protective boards can be installed to avoid over charging and over discharging of batteries, thus prolonging the service life of batteries.


4. The voltage of lithium-ion batteries with high voltage is generally 3.6V, 3.8V and 4.2V, which is much higher than the 1.2V voltage of nickel-cadmium and nickel-hydrogen batteries.


5. There is no memory effect. It is not necessary to empty the remaining electricity before charging, so it is convenient to use.


6. Small internal resistance: The internal resistance of the cylindrical core is smaller than that of the general liquid cell. The internal resistance of the domestic cylindrical cell can even be below 35m, which greatly reduces the self-consumption of the battery and prolongs the standby time of the mobile phone, and can fully meet the international standards. This polymer lithium-ion battery, which supports large discharge current, is an ideal choice for remote control model and is the most promising alternative to nickel-hydrogen batteries.


7. Li(NiCoMn)O2 lithium battery packs can be assembled in series or in parallel


8. Wide range of applications: notebook computers, walkie-talkies, portable DVD, instruments, audio equipment, aeromodelling, toys, cameras, digital cameras and other electronic equipment.

 

Disadvantage

The biggest disadvantage of Li(NiCoMn)O2 lithium batteries is that their size has been fixed, and they are not well positioned in some notebooks or products. Of course, this disadvantage can also be said to be an advantage. This is a disadvantage compared with other lithium batteries, such as polymer lithium batteries, which can be customized and changed in size. Compared with some products with specified battery specifications, it has become an advantage.

 

Li(NiCoMn)O2 lithium batteries are prone to short circuit or explosion, which is also relative to polymer lithium batteries. If compared with ordinary batteries, this disadvantage is not so obvious.

 

The production of Li(NiCoMn)O2 lithium batteries requires protective circuits to prevent the battery from discharging due to excessive charge. Of course, this is necessary for lithium batteries, which is also a common disadvantage of lithium batteries, because the materials used in lithium batteries are basically lithium cobalt oxide materials, and lithium cobalt oxide materials lithium batteries can not discharge at high current, and the safety is poor.

 

Li(NiCoMn)O2 lithium batteries require high production conditions. Compared with general battery production, Li(NiCoMn)O2 lithium batteries require high production conditions, which undoubtedly increases production costs.

 

If you can't find a battery that meets your requirements on this page, please contact Geilienergy lithium battery suppliers for more information about our custom battery packs.

 

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