Author ：Iflowpower – Portable Power Station Supplier
More than three hundred years ago, Benjamin Franklin began to capture lightning, opening up people's understanding of lightning, and opened up people's understanding of electricity, starting at that time, there are also many people to consider how to store captured electricity So, gradually, this kind of battery is born, real, as a very important invention in history, the appearance of the battery has been dealt with a lot of problems, and greatly improves various life efficiency, and the occurrence of lithium-ion batteries is more It has made people's understanding of electricity, and 18650 lithium-ion batteries is the most used time, and there is still a lithium-ion battery that still exists. It is possible to see the shadow of 18650 lithium-ion batteries in many local categories. Compared with other batteries, the advantages are very distinct, and safety is relatively good, even in large equipment, this article analyzes the knowledge of 18650 batteries, and analyzes why it will appear Explosion event.
1. 18650 lithium-ion battery advantage generally believes that the no-load voltage of the lithium-ion battery is considered to be electrically used (detailed value to see the threshold of the battery protection board, such as low to 2.8V, also 3.
2V of). 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 Can't test the battery, can't charge the battery). 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, and during the battery charging process, the voltage of the battery gradually rises from 3.7V to 4.
2V, lithium-ion battery. Charging cannot charge the no-load voltage above 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, in 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 less than 35MΩ, greatly reduce the self-consuming power of the battery, extend 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 does not have to take the remaining power 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%. For a short circuit of alert battery, the positive and negative of the 18650 lithium-ion battery is separate.
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 life of the life of 18650 lithium-ion battery is very long, the cycle life can reach more than 500 times during normal use, and it is more than twice the general 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 you break through 5000mAh. Second, 18650 lithium-ion battery classification 18650 lithium-ion battery processing must have protection lines, and the alert battery is over-filled. Of course, this is not obtained about 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 a lithium-cobalt-tissue material, while the lithium ion battery of lithium cobalt acid lithium ion battery cannot be large.
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 "dry state" or "colloid", and most of the polymer gel electrolyte is currently used.
In terms of solid state, strictly means that electrodes and electrolytes are solid. 3, 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 so-called polymer lithium ion battery refers to a lithium ion battery used as an electrolyte, and the detailed part is divided into two kinds of "semi-polymer" and "all polymers". "Semi-polymer" refers to a layer of polymer (typically PVDF) on the isolation membrane, making the electrical cells stronger, the battery can be done, its electrolyte is still a liquid electrolyte.
"All polymer" means that the gel network is formed inside the battery cell, and then injects the electrolyte to form an electrolyte. Although "all polymer" batteries still want to use liquid electrolyte, there is a lot of dosage, which has great improvement on the safety performance of lithium-ion batteries. According to the author, only Sony is mass production of "all polymers" 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 of the price is lower 18650 is about 1USD / PCS, and the words calculated according to 2ah. 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 major advantage of lithium-ion batteries, it is possible to design a unified standard according to the needs of customers, so it is basically the standard model of 18650 in the lithium-ion battery industry, and others are based on customers. Design. 3, the safety difference We understand the lithium-ion battery in extreme cases (such as overcharge, high temperature, etc.
), internally, there will be severe chemical reactions, sprouted a lot of gas. The 18650 battery uses the metal case, with a certain strength, when the internal air pressure reaches a certain amount of steel, the steel shell will break the explosion, an extremely terrible safety accident. This is also why the 18650 battery is generally not protected by layer, and it is absolutely not possible to enhance it.
The polymer battery does not have this problem, even if it is also in extreme case, since the packaging film strength is low, as long as the pressure is slightly higher, it will break, it will not be born to explode, the most harsh situation is burning. Therefore, from security, polymer batteries are better than 18650 batteries. 4.
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 uses in the use of lithium secondary batteries in the energy battery industry than 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 love for consumers.
Pay attention to the energy battery industry, adequately understand the battery, let us "use it for me", currently 18650 lithium-ion batteries have certain uses below. 1. Energy storage class is important for 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. V.
18650 Charge and discharge of lithium-ion batteries According to industry standards, the general nominal capacity is the minimum capacity in a batch of batteries, which is CC / CV0 in a batch of batteries. 5C full, after standing for a period of time (usually 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 by the lithium ion battery, the charge is required to terminate the charging due to the increase in the increase of temperature rise. 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 test point, the over-discharge protection, abstain discharge, and maintain 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 short-circuited, 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 Lithium-ion battery charging principle The working principle of lithium ion battery is to refer to the principle of charge and discharge. 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 during the charge and discharge of the lithium ion battery, lithium ions are in the motion state of the positive electrode → negative electrode → positive electrode. If we compare the lithium-ion battery image as a rocking chair, the two ends of the rocking chair are the two poles of the battery, and the lithium ions are like excellent sports, run back in the rocking chair. So, experts gave a lithium-ion battery a cute name rocking chair battery.
Sixth, 18650 lithium-ion batteries Why have an explosion history 18650 Battery vast majority using a steel shell package, a battery that does not have to be closed, due to no protection function, in the case of overcharge (overcharge), it will increase its internal pressure, When you exceed the tolerance, you will explode. The short circuit, too high or battery extruded deformation or even puncture can cause battery explosion. After 30 years of development, the 18650 battery preparation process has been very mature, except for performance, its security is also very perfect.
In order to prevent the sealed metal housing explosion, the 18650 battery will be equipped with a safety valve at the top, the safety valve is the standard of each 18650 battery, but also the most important explosion-proof barrier. When the internal pressure of the battery is too large, its top safety valve will open the exhaust pressure reduced pressure to prevent explosion. However, after the safety valve is opened, the chemical that is disclosed inside the battery will chemically react with oxygen in the air under high temperature conditions, and still possible to appear.
In addition, this 18650 battery is also self-contained, with a full-filled and short-circuit protection, and the safety performance is very high. And the previous mobile power explosion event, all because no manufacturers use unqualified poor 18650 batteries, even second-hand waste electricity. At present, the 18650 batteries that have been processed by major batteries such as Panasonic, Sony, Samsung and so on are actually very safe, and the 18650 battery usage is very high.
We can do correct use when we use and prevent battery short circuits, damage or Too high temperature, do not have to worry about the battery explosion. We can't overturn a boat, with individual inferior products to be qualified 18650 security. Seven, 18650 lithium-ion battery video summary: In fact, there is also a cost of explosion, which will be appreciated by the explosion.
After all, the grasp of this stability will not be so powerful, but 18650 as a performance A lithium-ion battery, which will definitely be more extensive, after all, in this indispensable battery, 18650 lithium-ion battery is the best choice. .
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