▲ The picture shows walking on the streets of New York with DynaTAC in the 1980s
In 1973, Motorola engineer Martin Cooper walked the streets of Manhattan with a brick mobile phone and called Bell Labs, a rival who was also researching mobile phones.
This is the first time that a telephone signal has been separated from copper wire transmission, but this phone call cannot be talked for too long, because the DynaTAC held by Martin Cooper can only provide 35 minutes of talk time, and for this battery life, it needs to charge 10 hour.
Motorola also knows that almost half a day of charging time is unrealistic for businessmen who cherish time and money, so it launched another set of charging accessories. The charging time was controlled within 1 hour. This may be the first time in the history of mobile phones. A set of fast charging device.
Is battery life anxiety really unsolvable?
Since the mobile phone was separated from the cable, people's anxiety about power has never stopped. The battery level of a mobile phone is like the balance of a wallet. Every drop in the battery makes people feel anxious, and only a little bit of rise can make you feel at ease.
There are many ways to alleviate battery life anxiety. The most direct way is to replace the mobile phone with a large battery that can last longer. However, the volume of the battery left by the mobile phone is ultimately limited, and the capacity cannot be increased endlessly.
Since it is difficult to solve the problem from the inside of the mobile phone, manufacturers try to find a breakthrough from the outside of the mobile phone.
The battery life of the mobile phone is composed of two parts of the experience, one is the power consumption of the mobile phone, and the second is the charging speed. If the former is difficult to extend, shortening the charging time as much as possible can also improve the battery life experience of the mobile phone.
And when smart phone manufacturers realized that the charging of their phones was too slow, the time has come to 2010.
Although a hundred flowers flourished in the mobile phone market at the time, all "machines" were equal in the matter of charging-all were 5V1A.
In the same year, the USB-IF Association released a new charging protocol. The maximum charging power of mobile phones can reach 7.5W, and charging is finally no longer the same as 5W.
Three years later, the QC 1.0 protocol released by Qualcomm made more people aware of fast charging, and the charging power came to 10W. However, people's understanding of fast charging at the time was only "slightly faster charging."
In 2014, the VOOC flash charging on OPPO Find 7 pushed the charging power to 22.5W for the first time. The R7 series released a year later, with the viral slogan "Charge for 5 minutes and talk for 2 hours", made VOOC flash charging a household name.
It also started from the VOOC flash charging. The charging became faster and faster, and it became more and more complicated and fragmented. Major manufacturers have begun to introduce their own private charging protocols, and they are not compatible with each other.
In addition to VOOC flash charging, the USB Association's PD (including later PPS) protocol, Qualcomm's QC protocol, vivo's FlashCharging, Huawei's SuperCharge and other protocols are dazzling.
The fast charging field quickly formed two major schools. One is the high-voltage solution represented by Qualcomm's QC protocol, and the second is the low-voltage direct charging architecture represented by the OPPO VOOC flash charge.
The incompatibility of private fast charge protocols has greatly increased the cost of consumers: If you want to make your mobile phone use fast charge in the office, at home, and on the road, you need to learn the basics of the fast charge protocol first, and then look at it. The charging head does not match.
Fast charging was originally intended to solve the user's battery life problem, but as a result, it has brought new compatibility issues. The battery explosion incident five years ago and the sporadic charging accidents afterwards cast a shadow over the fast charging technology.
Time soon comes to 2020, OPPO, Xiaomi, vivo and other manufacturers have announced that their fast charging technology has exceeded 100 watts, and the charging time has been compressed to an astonishing 20 minutes. This is indeed a big improvement in charging speed, but at the same time, many users are beginning to worry: Is it really safe for me to use such a high power?
"Safety" always precedes "efficiency"
The story about the first mobile phone DynaTAC at the beginning is actually only half of it.
▲ The fast charge charger is also a big man
Although Motorola reduced the charging time from 10 hours to 1 hour, it had to pay a price for it. High-speed charging made DynaTAC's battery very hot, which not only shortened the battery's service life, but may also cause a short circuit.
It sounds like the battery charging efficiency and safety seem to be a contradiction?
This is because the nickel-chromium battery used in DynaTAC is one of the most difficult to charge. In contrast, the lithium-ion battery structure used in modern mobile phones is much safer, it can withstand higher voltages and is more stable. it is good.
▲ Behind the leap in speed is also the advancement of battery technology
The battery structure is like the cornerstone of charging. Only if it is solid enough can it build a faster and safer charging experience.
On OPPO's annual flash charging open day, OPPO shared a new charging safety design that includes a number of technological breakthroughs. Let's take a complete charging process as an example to detail how the new safety design improves charging safety.
First of all, before the current is input to the battery, it has to go through various "checkpoints" to control. OPPO has applied overload protection technology on the charging head, charging interface, and battery end. If current overload is detected in any link, it will turn off the switch in time to protect the battery.
Even if these lines of defense all fail at the same time, there is the last physical line of defense inside the battery. OPPO has added fuse protection to the battery, which is equivalent to a fuse, which cuts off the current input through physical fuse to protect personal safety.
The fuse provides a physical level of protection for the battery, but due to its large internal resistance, it will inevitably cause the battery to locally heat up.
So OPPO has further upgraded the fuse, the internal resistance of the new generation of fuse has been reduced by half, and the efficiency and safety of charging have been improved.
Not only that, OPPO also uses GaN (gallium nitride) materials in mobile phones.
GaN semiconductor should be the "net celebrity" in the current charging industry. Compared with traditional silicon materials, its conversion efficiency is higher. This makes many high-power chargers who want to maintain a "compact" body prefer GaN materials.
There are many tiny electronic switch tubes inside the mobile phone. These small switches made of silicon play a role in current management and safety protection.
OPPO plans to replace these electronic switch tubes with GaN materials with a lower impedance ratio, which can effectively reduce the heat generated by the battery and keep the battery working in a safer state.
In addition to battery materials, the arrangement and combination of batteries will also affect the safety performance of the battery.
When OPPO launched the 50W super flash charging technology in 2015, it was the first to adopt the design of series double cells, using the principle of series voltage division to reduce the heat of the battery, and the energy is evenly divided, reducing the safety risk of the battery.
Now, OPPO wants to "put back together" the two batteries. OPPO introduced a layer of special material between the two batteries so that the two batteries can be placed in a packaging bag without interfering with each other, and the new design can increase the battery capacity by at least 5%.
In other words, the original 4500 mAh battery can be upgraded to 4750 mAh, and the extra power is enough to make you play the king again.
It is not enough to have a dual-cell internal string. Under long-term use, the voltage drop inside the cell will easily accumulate a certain safety risk. In order to discover potential hidden dangers in time, OPPO has specially developed a battery safety detection chip.
Simply put, this chip is like a "post" of the battery, which can automatically detect and analyze the working status of the battery. When an abnormality occurs, it will prompt the user through the system to repair or replace the battery as soon as possible.
As mentioned earlier, the stability of lithium-ion batteries is very good, but there is also a prerequisite, that is, the battery should not be damaged by any external force.
▲ Ordinary battery acupuncture test demonstration, shooting under special circumstances, please do not imitate
Since lithium is a very active element, when a lithium-ion battery is damaged and causes a short circuit, it is easy to catch fire, smoke or even explode.
▲ Demonstration of acupuncture test of sandwich safety battery, shooting in special environment, please do not imitate
However, this problem was finally solved in OPPO's "sandwich safety battery". Even in the face of extreme acupuncture and heavy hitting tests, the "sandwich safety battery" will not have problems such as spontaneous combustion and explosion.
▲ Demonstration of heavy blow test of sandwich safety battery, shooting in special environment, please do not imitate
This is because OPPO uses a new type of composite material as the matrix, and a layer of aluminum foil is plated on both sides of the composite material through a very difficult process to form a "sandwich" structure "current collector". In order to further enhance safety, OPPO coated a layer of safety protection layer on both sides of this "collector". Based on this, there is a "sandwich safety battery" that is not afraid of needle sticks and heavy blows.
If the "sandwich safety battery" solves the safety risks caused by external force damage from the structural level, then low-impedance fuses, gallium nitride electronic switches, internal series double cells and battery safety detection chips are used as a set of " "Combination boxing" solves the safety risks from the internal battery and the synergy of components in daily use.
In the current mobile phone charging power competition, OPPO's new safety design will help expand the safety margin of fast charging technology and provide users with higher safety guarantees. And this is the technical promise most needed in the fast charging field.
"Speed" is not the only ruler of fast charging technology
The continuous innovation of fast charging technology is based on a sufficiently wide safety margin, but safety is far less obvious and perceptible than charging power or charging speed. When the structure of the mobile phone battery is sufficiently safe, charging will no longer be limited to the power wattage, but will become more diverse.
Take OPPO's newly released smart charging technology as an example. In daily situations, the battery temperature of Super VOOC will be controlled within an appropriate range when charging.
And when we are in a hurry to go out but the battery is seriously low, then we can enable the "full blood charging" mode to increase the charging speed by 20% and restore more security in a short time.
Or in some extreme environments, for example, when the temperature is below zero in winter in the north, mobile phone batteries often lose power or fail to charge due to the low temperature.
At this time, the mobile phone can keep the battery temperature above 10°C through self-heating, thereby returning to the normal charging speed.
Fast and slow charging speed is no longer the only criterion for measuring fast charging technology. The exploration of battery technology allows fast charging to solve some of the pain points in our lives. Fast charging has also become a problem that many people can’t go back after using up. One of the functions.
According to data released by OPPO, the number of users using VOOC flash charging worldwide has reached 195 million, and after years of development, VOOC flash charging has formed a mature ecosystem of flash charging, super flash charging and wireless flash charging.
Unlike when VOOC first appeared in 2014, Find 7 users can only use their own charging kit to achieve fast charging. Now you can see the VOOC charging interface in the waiting room, high-speed rail station and other places, and there are many more firsts Fang and third-party accessories are optional.
At present, OPPO has opened the flash charging patent license to more than 40 manufacturers, and the increasing number of fast charging accessories has expanded the use of VOOC.
Looking back at the hard-to-unify fast-charging market, manufacturers seem to have fallen into the comparison of power figures. The pressure of this comparison makes manufacturers have an irrational pursuit of high-power charging.
Fast charging should not be just an icing on the cake, but a scene-based experience that allows users to think less and be more calm. This requires manufacturers to return to rationality, continue to consolidate the safety foundation, so that users can feel relieved.
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