Mobile power, commonly known as charging treasure, I think everyone is familiar with it, it is estimated that the majority of valued friends are at least one, some even several. Today's mobile hardware is becoming more and more powerful, but the cell phone battery technology seems to have encountered a bottleneck, and in recent years has not seen much development. In this context, mobile power came into being. In the early years, the price of mobile power was far too high. Now it's all right. The power of mobile power is not only bigger and bigger, but also the price is getting cheaper and cheaper. The small mobile power supply is simple and simple. It is nothing more than batteries, circuit boards, and housings. The batteries account for most of the cost. Today, I’ll talk about the core of the mobile power supply—cells. It helps when buying a mobile battery.
First, the introduction of two kinds of batteries
The figure above is the two mobile powers on my hand. The left side is the 10000mAh mobile power supply purchased from Anonai many years ago, and the right side is the mobile power supply of LeTV 13400mAh. From the front, it feels like it is a long point for Anonai.
Or take a look at the side of the bar, An Neng Tai's thickness is significantly thinner than LeTV's, An Entai's mobile power supply thickness of 12mm, and LeTV's mobile power supply thickness of 22mm, a difference of nearly two, which Why is it?
Let’s introduce the next two types of batteries.
At present, the mobile power cells in the market are generally divided into two types of lithium polymer batteries and lithium ion batteries . Lithium polymer batteries are actually called lithium ion polymer batteries, so lithium polymer batteries are actually a type of lithium ion battery. . From the internal structure, the biggest difference between lithium polymer batteries and lithium-ion batteries is the difference in electrolytes. Lithium polymer batteries use solid or gel polymer electrolytes. Lithium-ion batteries use liquid electrolytes. From the appearance of the shape, the lithium polymer battery is generally blocky, length and width can be any size, and lithium-ion batteries are generally cylindrical, the most common is the 18650 batteries, shape than the traditional number 5 The dry battery is bigger.
The figure above is the 18650 battery, this battery is a strong light flashlight, in fact, the mobile power of lithium-ion batteries is a multi-section of such batteries made in series.
Here we should understand why the thickness of the two mobile power supplies in the picture above will be so much different! Anontai's mobile power supply uses a lithium polymer battery, so the thickness can be as thin as 12mm, and the theoretical minimum thickness can be as low as 0.5mm. The Levis' mobile power supply uses a lithium-ion battery, which is 18650. Batteries. In fact, 18650 is the size of the model, 18 is 18mm diameter, 650 height is 65.0mm. Since the diameter of 18mm, then the use of this 18650 cell mobile power supply thickness of at least 20mm or more, you think the battery diameter is 18mm, but also with the shell, so that the above figure in the mobile power 22mm Thickness is no longer normal. Then, when you buy a mobile power supply, it becomes clear that you can use the thickness of the mobile power supply to determine which cell you are using, even if it is not indicated on the outer package.
18650 battery size measurement, diameter 18mm, length 65mm.
In addition, lithium polymer batteries have a higher energy density than lithium ion batteries, which means that lithium polymer batteries have the advantages of lighter weight and higher capacity in the same volume.
Second, the safety of batteries
In the eyes of the average consumer, it is certain that lithium-polymer batteries are more stable and safer than lithium-ion batteries. I thought so a few years ago, so I bought a mobile power supply for lithium polymer batteries. actually not.
However, most people think that lithium-polymer batteries are safer than lithium-ion batteries because lithium ions that use liquid electrolytes increase their internal pressure in the event of overcharging. Therefore, in order to avoid the explosion of the sealed metal housing, Generally, this kind of 18650 battery will be equipped with a safety valve at the top. When the internal pressure of the battery exceeds a certain value, the safety valve at the top of the battery will pop up automatically to reduce the pressure. However, when the safety valve pops up, lithium ions leaking from the inside of the battery will come into contact with oxygen in the air, and it will still cause a fire. In fact, the big brands of lithium-ion batteries still have a good safety guarantee, but some cottage manufacturers in order to pursue profits to produce some unqualified batteries, made everyone alarmist.
Of course, for the mobile power supply using this lithium-ion battery, the internal circuit board design is relatively more important. Short circuit design, power overload design, charge and discharge design, etc. seem simple, but when the batteries are in danger, they must be powered off automatically to ensure the safe use of mobile power.
At present, lithium-ion battery technology has developed relatively well. The safety of lithium-ion batteries produced by regular large manufacturers is actually not worse than that of lithium-polymer batteries, and most notebooks on the market will not use such lithium-ion batteries. .
Third, the battery life
The lifespan of the mobile power cell is related to the number of completions of the charging cycle, and it is not directly related to the number of charging cycles. To give a simple example: on the first day, half of the electricity was used, and then the electricity was recharged. On the second day, it was still half full and then it was full. It was a total of two down times and it was only one charge cycle, not two. Therefore, in general, one cycle is completed after several times of charging in daily use, and the amount of electricity is reduced by one point for each charging cycle. However, the extent of this reduction is very small. After a good lithium battery has been charged for many cycles, it can still maintain a relatively high power. The use of reliable lithium batteries for two or three years is not a problem.
Lithium battery life is generally 300 to 500 charge cycles. Under simple calculations, it is assumed that the quantity of electricity provided by one complete discharge is Q. If the reduction of the quantity of electricity is not considered after each charging period, the lithium battery can provide a total amount of power of 300Q-500Q during its life. Through this calculation, we can see that if you charge with half the power each time, you can charge 600-1000 times; if you charge with 1/3 of the power each time, you can charge 900-1500 times. Above by calculating two random examples, through these two examples we can see that lithium batteries can be used with the charge, in short, regardless of how charge, charge a total of 300Q ~ 500Q power. Therefore, the lifespan of the mobile power cell is related to the number of completions of the charging cycle, and it is not directly related to the number of charging cycles.
After reading the above, each value friend should be very clear, when using lithium battery related products, everything is convenient, can be used with the charge, do not have to worry about impact on lithium battery life, of course, at least deep every month Charge deep for 1 time to calibrate the lithium battery's power. In addition lithium batteries are more afraid of high temperature and low temperature, it is best to use and charge and discharge in a suitable temperature range.
Fourth, the price of batteries
After many years of development of lithium-ion batteries, the technology is relatively mature, and the large-scale production has made its manufacturing costs very low. Therefore, lithium-ion batteries have more advantages in price than lithium-polymer batteries. Currently, most laptops on the market use lithium-ion batteries. For reasons of cost, even Tesla's electric vehicle power supply system uses 18650 batteries. There were news reports about Tesla and others. Japanese 18650 battery makers signed a cooperation agreement.
The figure above shows Jingdong Mall's top 10 mobile power sales. There are 7 mobile power sources for lithium battery cells, and the top 5 are all lithium ion batteries. For lithium polymer batteries, lithium ion batteries The price is cheaper and more cost-effective, so it is more popular with consumers.
Take the millet 10000mAh mobile power to compare
Lithium-ion batteries are used as the mobile power source for the batteries, with a capacity of 10000mAh and Jingdong selling for 69 yuan.
Lithium polymer battery as the mobile power of the battery, the capacity of 10000mAh, Jingdong sells for 149 yuan.
The above two models are the same as millet's mobile power supply, and the battery capacity is 10000mAh, but the price difference is a full double, so the price of the two batteries do not need to say it, the above two mobile power is very Good representative.
Fifth, the battery capacity
10000mAh Lithium Polymer Power Bank
13400mAh lithium-ion mobile power
The first thing I want to say is that when you choose a mobile power source, the bigger the capacity, the better. As the name implies, mobile power needs to be moved, which means that you must consider its size and weight when you choose to purchase. Some tens of thousands of milliamperes of lithium-ion batteries have a relatively large volume and weight of mobile power (relatively small dots of lithium polymer batteries), and although they have sufficient power, they lose their mobility. Of course, before you buy mobile power, you also need to know the battery capacity of your daily use of the device, which can also roughly estimate the capacity of mobile power suitable for your needs. Of course, you also need to consider the loss of the mobile power itself when it is discharged. In addition, if the mobile power supply is too large, the security loss will be irreparable.
I personally feel that the mobile power of 5000~10000mAh is the most suitable, and the capacity is too big to be wasted. Of course, if you have special needs, it is a different matter. The large-capacity mobile power supply is bound to be bulky and heavy, which will result in greatly reduced portability and no portability.
Finally, if you are more value-conscious, if you prefer the 18650 lithium-ion battery mobile power, if you like the kind of ultra-thin design, stylish mobile power, then you can choose the mobile power of lithium polymer batteries, of course Regardless of the type of mobile power you buy, you must choose a well-known brand, and you must purchase it in a regular store, because the bigger the brand, the more knockoffs will be.
