Charging principle and positive & negative electrode judgment of 18650 lithium-ion battery

Some chargers use inexpensive solutions. If the control accuracy is not good enough, it is easy to cause abnormal battery charging or even damage the battery. Choosing a popular brand of 18650 lithium-ion battery charger not only can ensure the quality and after-sales but extend the service life of the battery. The 18650 lithium-ion battery charger guaranteed by the brand has four protections: short circuit protection, overcurrent protection, overvoltage 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 internal pressure rise caused by the temperature rise.

Therefore, the protection device needs to monitor the battery voltage. When it reaches the overcharge voltage of the battery, it activates the overcharge protection function and stops charging. Over discharge protection: to prevent the lithium ion battery over discharge state, when lithium ion battery voltage is lower than the discharge voltage testing point, namely the activation over discharge protection, suspend the discharge, and keep the battery in low static current standby mode. Over current and short circuit protection: when the lithium ion battery discharge current is too large or short circuit occurs, the protection device will activate the over current protection function.

The lithium battery Charging control is divided into two phases. The first stage is the constant current charging, when the battery voltage is lower than 4.2 V the charger will be at a 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 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). Cut off the charging circuit, the indicator light is on and the charging is completed.

Excessive charge and discharge of lithium ion battery will cause permanent damage to the positive and negative poles. Lead to excessive discharge cathode carbon layer structure appeared to collapse, and failures can cause in the process of charging lithium ion cannot insert. Overcharging causes too many lithium ions to be embedded in the negative carbon structure, so that some of them can no longer be released.

Charging principle of 18650 lithium battery

The working principle of lithium-ion battery is refers to the principle of charging and discharging. When charging the battery, the battery has lithium ions generated in the anode, the generated lithium ions through the electrolyte to the negative movement. As a cathode carbon layer structure, it has a lot of pores and the lithium ions that go to the negative end are embedded in the pores of the carbon layer. The more lithium ions are embedded, the higher the charging capacity.

Likewise, when the battery is discharged (the process by which we use the battery), it is embedded in the cathode carbon layer of emergence, lithium ions and movement back to the anode. Back to the anode of lithium ion, the more the higher the discharge capacity. We usually mean by battery capacity is the discharge capacity.

It is not hard to see, in the process of charging and discharging lithium ion batteries, lithium ion in the motion state from the positive and negative to the anode. If we think of lithium ion battery as a rocking chair, the two ends of the rocking chair are the two poles of the battery, and lithium ion is like a good athlete, running back and forth on both ends of the rocking chair. So experts have come up with a cute name for lithium-ion batteries: rocking chair batteries.

18650 the application of lithium batteries

The application of lithium secondary battery in energy battery industry benefits from its superior performance. With the development of lithium secondary battery technology has been widely used in our daily life. Repeated use of rechargeable batteries is more and more get the favour of consumers. Pay attention to the energy battery industry, and fully understand the battery so that we can do "for our own use". At present, 18650 lithium battery has some applications in the following fields:

1, energy

it is mainly applied to the base station power supply, clean energy, energy storage, grid power energy storage, domestic optical storage system, etc.

2, power

Mainly refers to electric vehicles, electric bicycle, new energy vehicles, etc.

3, digital

Mobile phone, tablet, notebook computers, electric toys, MP3 / MP4, headphones, charging treasure, model aircraft, mobile power supply, etc.

Three ways to determine the positive and negative electrodes of 18650 lithium battery

Method 1: 18650 lithium battery convex head is positive, flat is negative.

Method 2: If you measure it with a multi-meter, the red and black pen, the red line is + when it's positive, the black line is - when it's negative. The red pen corresponds to the - electrode and the black pen corresponds to the + electrode.

Method 3: Look at the screen, if there is a screen printing on the positive screen, is generally left positive and right negative.

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