What is the difference between power lithium battery and capacity lithium battery?

Lithium-ion batteries are new energy vehicles power lithium battery, according to the characteristics into power, energy and power energy balance type 3 kinds. Power type that you talk about power lithium battery main characteristic is to support large ratio of charge and discharge, typically up to 10 c above, the parameters of the main consideration is than function (W/kg).Type of energy is the key features of specific energy (Wh/kg).Analogy is capacity model is a marathon runner, must have the stamina, capacity is bigger, the large current discharge performance is generally not high; Power type is sprinter, spelling is the force of the outbreak, but endurance also should have, or ran near capacity is too small.

Type of lithium battery and power energy is accompanied by the emergence of plug-in hybrid and appear.Stored energy is higher, it requires that the battery can support a range of pure electric drive, also want to have good power characteristics, when low battery into a hybrid model.

18650 is lithium ion batteries granddaddy of Japan's SONY company in order to save cost and set a standard of lithium ion battery model, including 18 said to 18 mm in diameter, 65 said length is 65 mm, 0 means for cylindrical batteries.

Common batteries are divided into 18650 lithium ion battery,lithium iron phosphate batteries.For the nominal voltage of 3.7 v lithium ion battery voltage, charging by the voltage of 4.2 v, the nominal voltage of 3.2 v lithium iron phosphate battery, charge cut-off voltage of 3.6 v, the capacity is 1200 mAh - 3350 mAh, usually common capacity is 2200 mAh - 2600 mAh.

Lithium battery (Li - ion, lithium ion battery) : lithium ion battery has a light weight, large capacity, no memory effect, etc, and widely application, many digital devices are used the lithium ion battery as a power source, although its price is relatively expensive.High energy density lithium ion battery, its capacity is the same weight of 1.5 to 2 times of nimh batteries, and have very low self-discharge rate.In addition, the lithium ion battery has almost no "memory effect", and does not contain toxic substances etc also is the main reason that it is widely used.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.Standard 3.7 V or 4.2 V lithium-ion batteries are the same.Manufacturers of different and just yourself.3.7 V means the battery discharge platform in the process of voltage (i.e., a typical voltage), and 4.2 V refers to the charging full of electric voltage.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, (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 believed to be the no-load voltage of lithium-ion batteries in the 3.0 V is considered under the electricity used up (a specific threshold value needs to see battery protection board, such as low to 2.8 V, there is also a 3.2 V).Most of the lithium battery discharge cannot be under no-load voltage to 3.2 V, or excessive discharge will damage the battery (lithium batteries on the market commonly basic is belt protection board to use, so the excessive discharge can also lead to detect the battery protection board, thus unable to recharge the battery).4.2 V is the highest limit of the battery voltage, it is generally believed to the no-load voltage of lithium-ion batteries charged to 4.2 V is considered the electricity, the battery charging process, the battery voltage rise gradually in 3.7 V to 4.2 V, lithium batteries cannot be no-load voltage to over 4.2 V, otherwise will damage the battery, this is the place where special lithium-ion batteries.

18650 battery life theory as the charging circuit 1000 times.As the density of the unit capacity is very big, so most of the laptop battery, in addition, in 18650 at work stable performance is very good, is widely used in the electronics field: commonly used in high-grade light flashlight, portable power, wireless data transmission, electric thermal clothing, shoes and portable instruments and meters, portable lighting, portable printers, industrial equipment, medical equipment, etc.

18650 mean, 18 mm in diameter, 65 mm long.And 5 battery model is 14500, diameter of 14 mm, 50 mm long.General 18650 batteries in industry, with more civilian rarely, common in laptop batteries and use more high-end flashlight.

18650 is just the size of the battery model, according to the types of batteries can also be divided into, lithium ion, 18650, 18650 of the lithium iron phosphate, 18650 (rare), nickel metal hydride is common 18650 lithium ion.

Charge and discharge principle

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 many pores, arrived in the cathode of lithium ion is embedded into the microporous carbon layer, the embedded lithium ion, the more the higher the charge capacity.

Likewise, when to discharge the battery (i.e., we use the battery process), 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 compared the image of the lithium ion battery as a rocking chair, rocking chair at both ends of the poles for the battery, and lithium ion as excellent athlete, running to and fro in the ends of the rocking chair.So, the experts gave lithium ion battery rocking-chair batteries a cute name.

Charge and discharge process

Lithium battery charging control is divided into two phases, the first stage is the constant current charging, 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 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.

Lithium ion battery over charge and discharge can cause permanent damage to is negative.Lead to excessive discharge cathode carbon layer structure appeared to collapse, and failures can cause in the process of charging lithium ion cannot insert;Overcharge lithium ion anode carbon embedded structure of too much, and cause some of the lithium ion can no longer be released.

Some charger use cheap plan implementation, on the control accuracy is not good enough, easy to cause the battery is unusual, even damage the battery. The charger when choose and buy as far as possible choose a big brand of 18650 lithium-ion battery charger, guaranteed quality and after-sale, prolong the service life of batteries. Brand protection 18650 lithium ion battery charger has four heavy protections: short circuit protection, over current protection, over-voltage protection, the battery reverse connects protection function, etc. Over charging protection: when the charger for lithium ion battery charging, in order to prevent due to temperature rise caused by internal pressure rise, need to terminate the charging status. Therefore, protection device monitor the battery voltage, when it arrived in battery charging pressure, namely activation over charging protection function, to suspend the charge. 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.

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