wrong!wrong!wrong!Don't charge the phone like this

In the current life, mobile phones are not only communication tools, but also play an increasingly important role in work, leisure and social. In the process of using mobile phones, the most anxious is the low -power reminder of the mobile phone.

LG conducted a survey in 2016, showing that 90% of people felt "panic" when mobile phone power was lower than 20%. Although major manufacturers are working hard to expand the capacity of mobile phone batteries, as the frequency and intensity of mobile phones in daily life continues to rise, most people have gradually changed from one day to N charging, even many even many, and even many. When people go out, they will bring charging treasures to prepare from time to time.

So, when we use mobile phones in daily life, how can we do the life of the mobile phone battery as much as possible?

01

Lithium ion battery work principle

At present, the batteries used by most mobile phones on the market are the results of the Nobel Prize -lithium -ion battery. Compared with traditional batteries such as nickel -metal hydride, zinc -manganese, and lead storage, lithium -ion batteries have the advantages of large capacity, small volume, high voltage platform, long cycle life and other advantages. To the smaller shape and more lasting battery life.

Lithium ion batteries in mobile phones usually use LICOO2 (lithium cobaltate), NCM, and NCA materials; negative materials in mobile phones are mainly artificial graphite, natural graphite, MCMB, SIO, etc. During the charging process, the lithium is deified from the positive electrode in the form of lithium ions, and the electrolyte moves into the negative electrode through the electrolyte, while the discharge process is exactly the opposite. Therefore, the process of charging and discharge is the cycle of lithium ions that is continuously embedded/de -embedded, and inserted/off -insertion between positive and negative electrodes, which are vividly called "rocking chair batteries".

Lithium battery working principle: Lithium ions are continuously round trip with positive and negative poles with charging. The picture comes from the author

02

Causes of lithium -ion battery life decline

The newly bought mobile phone has a good battery life at the beginning. After a period of time, it will become more and more durable. For example: After the new mobile phone is fully charged, it can be used for about 36 to 48 hours, but After half a year, Mange and Power can only persist for 24 hours or even shorter.

What is the reason why the mobile phone battery is "folded"? The main reasons are the following points:

① Excess and off

Lithium ion battery relies on lithium ions to move between positive and negative electrodes. Therefore, the number of lithium ions that can accommodate lithium -ion batteries can be directly related to its capacity. When the lithium -ion battery is fully charged, the structure of the positive and negative electrode materials may be damaged, the space that can accommodate the lithium ion becomes less, and its capacity will be reduced. Essence

Before 50 times (A) (B) LICOO2 orthopedic material electron microscope shooting results

The battery life is usually evaluated with a cycle life, that is, deep charging and discharge of lithium -ion batteries, and its capacity can be maintained at more than 80% of the charging and discharge cycle.

The national standard GB/T18287 requires no less than 300 lithium -ion battery life in the mobile phone. Does this mean that our mobile phone battery will become durable after 300 charging and discharge? the answer is negative.

First, in the measurement of cycle life, the attenuation of the battery capacity is a gradient process, not a cliff -type or step -level; second, the lithium -ion battery is deeply charged and discharged. In the daily use process, the battery The management system has a protection mechanism for the battery. After full, it will automatically power off. When the power is insufficient, it will be automatically shut down. It can avoid deep charging and discharge as much as possible. Therefore, the actual life of the mobile phone battery is higher than 300 times.

However, we cannot rely entirely on the excellent battery management system. It may also damage the battery to the battery to reduce the capacity and reduce its capacity. Therefore, the best way to charge the mobile phone is to be shallow and shallow. When you do not use your mobile phone for a long time, maintaining half of its electricity can effectively extend its service life.

② Charging under too cold or overheating conditions

The lithium -ion battery also has high requirements for temperature, and its normal work (discharge) temperature range is between 0 ° C and 35 ° C. Under low temperature conditions, decreased electrolyte ion conductivity, increased charging impedance, and the performance of lithium ion batteries will deteriorate, and intuitive feelings are reduced capacity. However, the attenuation of this capacity is reversible. After the temperature is returned to room temperature, the performance of the lithium -ion battery will return to normal.

However, if the battery is charged under low temperature conditions, the negative polarization may cause its potential to reach the reduction of the metal lithium, which will cause lithium metal to deposit on the negative surface. This will lead to a decrease in the battery capacity. On the other hand, there is a lithium. The possibility of branch crystal leads to the short circuit of the battery and causes danger.

Charging lithium -ion batteries under high temperature conditions will also cause changes in the positive and negative electrode structure of lithium ions, resulting in an irreversible attenuation of the battery capacity. Therefore, trying to avoid charging mobile phones under too cold or overheating, it can also effectively extend its service life.

03

Are these claims reasonable about charging?

① Charging all night, will the service life of the opponent battery affect the service life?

Excessive charging and release will affect the life of the battery, but charging all night is not equal to overcharge. On the one hand, mobile phones will automatically disconnect after full power; on the other hand, many mobile phones currently use the capacity to charging the battery to 80% of the capacity, and then converted into a slower charging method of a relatively slow trickle charging. Therefore, you can charge your mobile phone with confidence while sleeping. These problem engineers have helped everyone to think about it during design. ② The weather is hot in summer, and the mobile phone will have high temperature when charging. Is this normal, or is there a problem with the mobile phone battery?

Battery charging is accompanied by complex processes such as chemical reactions and charge transfer. These processes are often accompanied by heat, so it is normal for mobile phones to heat up when charging. The high temperature hotness of mobile phones is generally caused by poor heat dissipation, rather than a problem with the battery itself. When charging, take the protective kit to make the mobile phone better heat dissipation, which can also effectively extend the service life of the mobile phone.

③ Charging the phone and the vehicle charger to the mobile phone will affect the service life of the mobile phone battery?

Won't. Whether it is a charging treasure or a vehicle charger, as long as it is charging the mobile phone with a national standard charging device, it will not affect the service life of the mobile phone battery.

④ Put a charging cable on the computer to charge the mobile phone, and charge the phone with the charging cable connected to the power socket on the power socket. Is it the same efficiency of charging?

Whether using charging treasures, vehicle chargers, computers, or directly inserted on the power supply, the charging rate is only related to the charger supported by the charger and the mobile phone support. Charger (9V = 2A) is slow.

⑤ Can the phone be used when charging? What causes the case of "calling to death when charging" that has appeared before?

The mobile phone in the charging state is available. When the mobile phone is charged, the charger will transform the 220V high -voltage AC electricity to power the battery through the transformer (such as the common 5V) DC. Only the low voltage part is connected to the mobile phone. Generally, the safety voltage of the human body is 36V. That is to say, under normal charging, even if the mobile phone leaks, the low output voltage does not cause damage to the human body.

As for the relevant news of "calling for call death during charging" on the Internet, it can be found that basically the content of the reprint can be found. sex. But as far as the use of national standards to charge mobile phones, "calling to be killed when charging" is alarmist. But this also reminds us that when charging mobile phones, we must use the charger that meets relevant national standards by regular manufacturers when charging mobile phones.

In addition, do not disassemble the battery independently during the use of mobile phones. When abnormal conditions such as drum packs in batteries, they should also stop using and replace them to mobile phone manufacturers in time to avoid safety accidents caused by improper battery use.

Author | Cao Bowei Physics Laboratory PhD student in the Institute of Physics, Institute of Physics of the Chinese Academy of Sciences

Source and Author: Scientific rumor, Cao Bowei

- END -