Mobile power those things: lithium polymer battery or lithium ion battery?

Mobile power, commonly known as charging treasure, I think everyone is no stranger to it, it is estimated that most valuable friends have at least one, and some even have a few. Today's mobile hardware is getting more and more powerful, but mobile phone battery technology seems to have hit a bottleneck and has not seen much development in recent years. In this context, mobile power came into being. In the early days, the price of mobile power was too high. Everything's fine now. The power of mobile power is not only getting bigger, but also getting cheaper. Small mobile power supply is simple and simple. It's nothing more than a battery, a circuit board, and a case. Batteries account for most of the cost. Today, I will talk about the core of mobile power - batteries. This is helpful when buying mobile batteries.

The following describes the two types of batteries.

At present, mobile power batteries on the market are generally divided into lithium polymer batteries and lithium-ion batteries. Lithium polymer batteries are also called lithium-ion polymer batteries, so lithium polymer batteries are actually a kind of lithium-ion batteries. From the internal structure point of view, the biggest difference between polymer Lithium Batteries and lithium-ion batteries is the difference in electrolyte. Lithium polymer batteries use solid or gel polymer electrolytes. Lithium-ion batteries use liquid electrolytes. From the appearance and shape, the polymer Lithium Battery is generally massive, the length and width can be any size, and the lithium-ion battery is generally cylindrical, the most common is the 18650 battery, the shape is larger than the traditional No. 5 dry battery.

18650 battery, this battery is a strong flashlight, in fact, the lithium-ion battery of the mobile power supply is made of several such batteries in series.

Mobile power supplies use lithium polymer batteries, so the thickness can be as thin as 12mm, and the theoretical minimum thickness can be as low as 0.5mm. The size of the 18650 lithium-ion battery model, 18 is 18mm diameter, 650 height is 65.0mm.

In addition, polymer lithium batteries have a higher energy density than lithium-ion batteries, which means that polymer lithium batteries have the advantages of lighter weight and higher capacity in the same volume.

Second, the safety of batteries

In the view of ordinary consumers, lithium polymer batteries are more stable and safer than lithium-ion batteries. I thought the same thing a few years ago, so I bought a mobile power supply with lithium polymer batteries. Actually, it's not.

However, most people believe that lithium-polymer batteries are safer than lithium-ion batteries because lithium ions that use liquid electrolytes increase their internal pressure when overcharged. Therefore, in order to avoid an explosion in the sealed metal housing, this type of 18650 battery is generally equipped with a safety valve at the top. When the internal pressure of the battery exceeds a certain value, the safety valve on the top of the battery will automatically pop out to reduce the pressure. However, when the safety valve is popped, the lithium ions leaking from inside the battery will come into contact with the oxygen in the air and still cause a fire. In fact, the big brand of lithium-ion batteries still have a good security guarantee, but some copycat manufacturers in order to pursue profits to produce some unqualified batteries, so that everyone alarmist.

Of course, for mobile power supplies using such lithium-ion batteries, the internal circuit is not the same.

At present, lithium-ion battery technology has been developed relatively well. The safety of lithium-ion batteries produced by regular large manufacturers is actually not worse than lithium polymer batteries, and most notebooks on the market will not use this lithium-ion battery.

Third, battery life

The life of the mobile power battery is related to the number of charging cycles completed, and has no direct relationship with the number of charging cycles. A simple example: use half the electricity on the first day and then recharge it. The next day, it's still half full, and then it's full. There are a total of two downtime, and only one charge cycle instead of two. Therefore, in general, in daily use, a cycle is completed after charging several times, and the power of each cycle is reduced by one point. However, the extent of this reduction is very small. A good lithium battery can still maintain a relatively high charge after multiple cycles of charging. Reliable lithium batteries last for two or three years.

The life of lithium batteries is generally 300 to 500 charge cycles. Simple calculation, assuming that the power provided by a full discharge is q, if you do not consider the reduction of power after each charging cycle, the total power that the lithium battery can provide in its service life is 300Q-500Q. Through this calculation, we can see that if you charge with half of the electricity each time, you can charge 600-1000 times; If you charge at 1/3 of the power each time, you can charge 900-1500 times. Above by random calculation of two examples, through these two examples we can see that lithium batteries can be used with charge, in short, no matter how to charge, the total amount of charging is 300Q ~ 500Q power. Therefore, the life of the mobile power battery is related to the number of charging cycles completed, and is not directly related to the number of charging cycles.

Read the above content, you should be very clear that when using lithium battery related products, everything is very convenient, can be used with the charge, do not worry about affecting the life of the lithium battery, of course, at least once a month to deep charge to calibrate the power of the lithium battery. In addition, lithium batteries are more afraid of high temperature and low temperature, it is best to use and charge and discharge in the appropriate temperature range.

Fourth, the price of batteries

After years of development, the technology of lithium-ion batteries is relatively mature, and large-scale production makes its manufacturing cost very low. Therefore, lithium-ion batteries have more advantages than lithium polymer batteries in terms of price. Currently, most laptops on the market use lithium-ion batteries. For cost reasons, even Tesla's electric vehicle power supply system uses 18650 batteries. There are news stories about Tesla and other companies. Japan 18650 battery manufacturers signed a cooperation agreement.

For polymer lithium batteries, lithium-ion batteries are cheaper and more cost-effective, so they are more popular with consumers.

Fifth, battery capacity,

The first thing I would say is that when you choose a mobile power supply, the larger the capacity, the better. As the name suggests, the mobile power supply needs to be moved, which means that you must take into account its size and weight when choosing to buy. Lithium-ion batteries of about tens of thousands of milliamps have a relatively large volume and weight of mobile power (relatively small lithium polymer batteries), and although they have enough power, they lose mobility. Of course, before buying a mobile power supply, you also need to understand the battery capacity of your daily use of equipment, so that you can roughly estimate the mobile power supply capacity suitable for your needs. Of course, you also need to consider the loss of the mobile power supply itself during discharge. In addition, if the mobile power supply capacity is too large, it will cause safety losses.