Author ：Iflowpower – Portable Power Station Supplier
More than three hundred years ago, Benjamin Franklin began to capture thunder and lightning, opened people's understanding of lightning, and opened people's understanding of electricity. From that time, many people are considering how to store captured electricity, so The gradual battery has appeared. It is indeed, as a very important invention in history, the emergence of the battery has indeed solved a lot of problems, which greatly improves various life efficiency, and the emergence of lithium-ion batteries makes people The awareness of electricity is getting deeper, and the 18650 lithium-ion battery is the most used time, and there is still a lithium-ion battery in many places.
It can see shadow of 18650 lithium-ion batteries because of this battery. Compared to other batteries, the advantage is very obvious, and safety is relatively good, and even has been used on large equipment. This article introduces you 18650 battery knowledge, introduces why the incident will have an explosion.
The 18650 lithium-ion battery generally believes that the no-load voltage of the lithium-ion battery is considered to be electrically used (the specific value should see the threshold value of the battery protection board, such as low to 2.8V, there are 3.2V).
Most lithium-ion battery discharges cannot ran out the no-load voltage or less, otherwise excessive discharge will damage the battery (the lithium-ion battery in the general market is basically used by protective boards, so excessive discharge can also cause the protector The battery is not detected, so that the battery cannot be charged). 4.2V is the highest limit voltage of the battery charging, which is generally considered to charge the no-load voltage of the lithium ion battery to 4.
2V. During the battery charging process, the voltage is gradually rising from 3.7V to 4.
2V, lithium-ion battery. Charging cannot charge the no-load voltage to more than 4.2V, otherwise the battery will also damage the battery, which is a special place for lithium ion batteries.
Generally, the 18650 lithium-ion battery has the following advantages. 1. Use the wide laptop, walkie-talkie, portable DVD, instrument, audio equipment, model, toys, cameras, digital cameras and other electronic devices.
2, series can be connected in series or in parallel into 18650 lithium-ion battery pack. 3, the internal resistance of the internal resistance small polymer battery is less than that of the general liquid cell, the internal resistance of the domestic polymer battery can even achieve 35m or less, which greatly reduces the self-consuming power of the battery, and extends the standby time of the phone. It can achieve the level of international lacking.
This polymer lithium-lithium-supported polymer that supports large discharge current is ideal for the remote control model, which is the most promising product of alternative nickel-hydrogen batteries. 4, no memory effect 18650 lithium-ion battery does not have to take the remaining electric quantity before charging, easy to use. 5, voltage high 18650 lithium ion battery is generally 3.
6V, 3.8V and 4.2V, far higher than 1.
2V voltage of nickel-cadmium and nickel-hydrogen batteries. 6, the safety performance of 18650 lithium-ion battery is high, no explosion, no burning; non-toxic, no pollution, through RoHS trademark certification; various safety performance is more than 500 times; high temperature resistance, 65 degrees The lower discharge efficiency is 100%. To prevent battery short circuit, the positive and negative of 18650 lithium ion batteries is separated.
Therefore, it may have dropped to the ultimate path. Can be installed to prevent the battery from being filled, so that the battery life can be extended. 7, the service life is 18650 lithium-ion battery has a long service life, and the cycle life can reach more than 500 times during normal use.
It is more than twice the ordinary battery. 8, the capacity of the large 18650 lithium-ion battery is generally between 1200mAh ~ 3600mAh, and the general battery capacity is only about 800, if combined with 18650 lithium-ion battery to become 18650 lithium ion battery pack, the 18650 lithium ion battery pack is casual Can break through 5000mAh. Second, 18650 lithium-ion battery classification 18650 lithium-ion battery 18650 lithium ion battery production must have protection lines, preventing battery from being filled with.
Of course, this is necessary for the lithium-ion battery, which is also a represession of the lithium ion battery, because the material employed by the lithium ion battery is basically the lithium-cobalt-tissue material, and the lithium ion battery of the lithium cobalt acid is not large current. Discharge, safety, from classification, the classification of 18650 lithium-ion batteries can be classified by the following manner. 1.
Press battery Practical performance classification power battery and energy-based battery. The energy-type battery is characterized by high energy density. It is important for high-energy output; the power battery is characterized by high power density, important for instant high-power output, output battery.
The power energy-type lithium-ion battery is accompanied by the emergence of plug-in hybrid vehicles. It requires a high energy stored in the battery, which can support a distance of pure electric travel, but also have better power characteristics, enter the hybrid mode at low power. Simple understanding, energy type is similar to marathon players, to have endurance, it is to require high capacity, the requirements for large current discharge performance is not high; then power type is a short runner, fighting is a full of outcomes, but the endurance must, otherwise too Small running.
2, according to the electrolyte material, a lithium ion battery is divided into liquid lithium ion battery (LiB) and a polymer lithium ion battery (PLB). Liquid lithium-ion battery uses liquid electrolyte (current power battery is more). The polymer lithium ion battery is replaced by a solid polymer electrolyte.
This polymer may be a dry state, or a colloidal state, and most of the polymer gel electrolyte is currently used. In terms of solid state, strictly means that electrodes and electrolytes are solid. 3, classified according to the product appearance 18650 lithium-ion battery is divided into: cylindrical, soft bag, square.
Cylindrical and square outer packaging is steel shell or aluminum shell. The soft bag is packaged as an aluminum plastic film. In fact, the soft bag is also a square, and the market is used to packaging aluminum plastic film is called soft bag, and some people call the soft bag battery as polymer battery.
About cylindrical lithium ion battery, model is typically 5 digits. The first two digits are the diameter of the battery, and the middle two digits are the height of the battery. Unit is mm.
For example, 18650 lithium-ion battery, has a diameter of 18 mm, height is 65 mm. 4. Positive electrode material according to a plate material: a lithium phosphate ion battery (LFP), a lithium-cobalt-ion battery (LCO), a lithium manganate ion battery, (dual battery: lithium manganese acid / nickel cobalt acid Lithium, (triple: nickel-cobalt-oxanate (NCM), lithium-nickel-cobalt-aluminate ion battery (NCA)).
Negative electrode material: a lithium titanate ion battery (LTO), graphene battery, nanocarbon fiber battery. The graphene concept on the market is important to the graphene battery, i.e.
, add graphene pulp in a pole, or add graphene coating on the membrane. Lithium nickel acid, the magnesium-based battery market is basically absent. Third, 18650 Lithium Ion Battery Comparison Polymer Battery 18650 Lithium Ion Battery The so-called polymer lithium ion battery refers to a lithium ion battery using a polymer as an electrolyte, in particular, divided into semi-polymer and all polymers.
The semi-polymer refers to a layer of polymer (generally PVDF) on the isolation membrane, making the electrical core more adhesion, the battery can be done, the electrolyte is still a liquid electrolyte. The full polymer refers to the use of a polymer to form a gel network inside the battery, and then inject the electrolyte to form an electrolyte. Although all polymer batteries still need to use liquid electrolyte, there is a lot of dosage, which is greatly improved on the safety performance of lithium-ion batteries.
According to the author, only SONY is in mass production allopolymer lithium ion batteries. In another aspect, the polymer battery refers to a lithium ion battery using an aluminum-plastic packaging film as an outer packaging, which is commonly known as soft bag battery. Such a packaging film is composed of three layers, which is a PP layer, an Al layer and a nylon layer.
Since PP and nylon are polymers, such a cell is called a polymer battery. 1. The price lower than the price of 18650 is approximately 1USD / PCS, and the words calculated according to 2ah.
3RMB / AH. The price of polymer lithium electricity, low-end cottage factory at 4RMB / AH, mid-end in 5 ~ 7RMB / AH, medium high end in 7RMB / AH or more. Like ATL, Lishen, usually can sell around 10RMB / AH, and you are still unwilling to pick up.
2, unbearable SONY always wants to make lithium-ion batteries like alkaline batteries, there is a certain industrial standard, just like 5 batteries, No. 7 batteries, all over the world basically. However, due to a large advantage of lithium-ion batteries, it can be designed according to customer needs, it is impossible to have a unified standard, so that the lithium-ion battery industry is basically only 18650 standard models, others are based on customers Design.
3, safety difference 18650 Lithium ion battery We understand that lithium-ion batteries are extremely chemical reactions in extreme cases (such as overcharge, high temperature, etc.), and a large amount of gas. The 18650 battery is used as a metal casing, with a certain strength, when the internal pressure reaches a certain step, the steel shell will rupture the explosion, an extremely horrible safety accident.
This is also why the 18650 battery is typically protected by layer, and it is absolutely not possible to enter the test. The polymer battery does not have this problem, even in extreme cases, since the packaging film strength is low, as long as the pressure is slightly higher, it will rupture, and there will be no explosion, the worst case is burning. Therefore, from security, polymer batteries are better than 18650 batteries.
4, the energy density is low in 18650 battery capacity to be 2200mAh, so that the energy density is approximately 500WH / L, while the energy density of the polymer battery is at a rate of close enough to 600Wh / L. But polymer batteries also have their own shortcomings. Important is costly, because it can be designed according to customer needs, the research and development costs in this will be counted.
Moreover, the shape is varied, which has a wide variety, resulting in a variety of tooling fixtures in the manufacturing process, and the corresponding new cost. The polymer battery itself is poor, which is also the flexible design, often to be re-designed for the customer for the difference between the two mm. Fourth, 18650 lithium-ion battery Application 18650 Lithium-ion battery in energy battery industry lithium secondary battery is benefited from its superior performance.
With the continuous development of lithium secondary battery technology, it has been widely used in our daily life; the rechargeable batteries used multiple times are more and more favored by consumers. Pay attention to the energy battery industry, fully understand the battery, let us do it for me, currently 18650 lithium-ion batteries have certain applications in the field below. 1, energy storage class importance to base station power, clean energy energy storage, grid power storage, home light storage system, etc.
2, powerful important refers to electric vehicles, electric bicycles, new energy vehicles, etc. 3, digital mobile phone, tablet, laptop, electric toys, MP3 / MP4, earphones, charging treasure, model, mobile power, etc. 5.
The 18650 lithium-ion battery charge and discharge 18650 lithium-ion battery is in accordance with the industrial standard. About the lithium-ion battery, the general nominal capacity is the minimum capacity, this capacity is a batch of batteries, under 25 degrees room temperature conditions, first CC / CV0.5C is full, and after standing for a period of time (generally 12 hours).
Take 0.2c current constant flow discharge to 3.0V (also standard is 2.
75V, but there is little effect, 3V to 2.75V decline, there is no much capacity), the capacity value of the discharged, due to a batch of batteries Difference, actually discharge the capacity value of the battery with the lowest capacity. That is to say, the actual capacity of any battery should be greater than or equal to the nominal capacity.
1,18650 Charging process of lithium-ion batteries Some chargers are implemented using inexpensive methods. It is not good enough in control accuracy, and it is easy to cause battery charging and even damage the battery. When purchasing charger, try to choose a large brand 18650 lithium-ion battery charger, quality and after-sales guarantee, extend battery life.
Brand protection 18650 lithium-ion battery charger has four protector: short circuit protection, overcurrent protection, overvoltage protection, battery reverse protection function, etc. Overcharge protection: When the charger is overcharged to the lithium ion battery, to prevent the increase in internal pressure due to rising temperature, it is necessary to terminate the charging state. To this end, the protective device needs to monitor the battery voltage.
When it arrives at the battery overcharge, the overcharge protection is activated, and the charging is suspended. Over-discharge protection: in order to prevent the over-discharge state of the lithium ion battery, when the lithium ion battery voltage is lower than its over-discharge voltage detection point, the over-discharge protection, the discharge is activated, and the battery holds the battery in a low static current standby mode. Overcurrent and short-circuit protection: When the discharge current of the lithium ion battery is too large or the short circuit occurs, the protection device will activate overcurrent protection function.
Lithium ion battery charging control is divided into a first stage of two phases is constant current charging. When the battery voltage is below 4.2V, the charger will charge a constant current.
The second stage is a constant voltage charging phase. When the battery voltage reaches 4.2V, due to the lithium ion battery characteristics, if the voltage is high, it will be damaged, the charger will be fixed at 4.
2V, and the charging current will gradually decrease. When the current decreases to a certain value (usually 1/10 set current), cut off the charging circuit, the charge is completed, and the charging is completed. Excessive charge and discharge of lithium ion batteries will cause permanent damage to the positive and negative poles.
Excessive discharge causes a collapse of the negative electrode carbon sheet structure, and the collapse can cause lithium ions in which lithium ions cannot be inserted during charging; excessive charging makes excessive lithium ions embed the negative carbon structure, resulting in some of the lithium ions and can no longer release. 2,18650 Charging principle of lithium-ion battery 18650 Lithium-ion battery lithium ion battery works refers to its charging and discharge principle. When charging the battery, there is a lithium ion form on the positive electrode of the battery, and the generated lithium ion is moved to the negative electrolyte.
The carbon as an negative electrode is laminated, and there is a lot of micropores, and the lithium ions reaching the negative electrode are embedded in the microporous of the carbon layer, the more lithium ions embedded, the higher the charging capacity. The same truth, when discharging the battery (ie, the process we use the battery), the lithium ions embedded in the negative electrode carbon layer, and move back to the positive electrode. The more lithium ions returned to the positive electrode, the higher the discharge capacity.
We usually say that the battery capacity refers to the discharge capacity. It is not difficult to see that the lithium ions are in the positive electrode during the charge and discharge process of lithium-ion batteries.
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