Today, the ordinary smartphone sports fantastic features. Frustrating only one thing - the battery, which is barely enough for a day of active work! In this post, we will discuss how and why power supplies have evolved in mobile phones and what are fast battery charging technologies. And at the same time we will dispel some old myths about the "correct" handling of batteries.
Hello, Habr! We are Anker, and this is our first, but far from the last, post on the Hubblog. In case someone else doesn't know, Anker is the world's largest manufacturer of mobile chargers for retail sales, founded by former Google engineer Stephen Young. However, our portfolio is not limited to exercises alone. The Anker brand sells a variety of USB cables and power banks, headphones and portable speakers, USB hubs, docking stations, and even robotic vacuum cleaners! And all this is our own development. We do not re-label other people's products. Anker employs hundreds of engineers doing real research, development and testing of new products.
In this blog, we will talk about technology through the prism of our specialization, share knowledge and insights from the international Anker team. We guarantee that you will not come across any intrusive advertising and marketing statements here. And right now we will take a little excursion into the history of charging mobile phones (our favorite topic). How the first mobile phones were charged, how fast charging technologies work and why it is high time to forget about the myths about batteries - here and now.
Batteries in phones the day before yesterday, yesterday and today
The history of phone batteries dates back to the 1940s, when police cars in St. Louis, pcs. Missouri, radio telephones appeared. They were powered by a car battery, one full charge of which was enough for about six short calls. The car battery was charged when the car engine was running. For several decades, mobile phones remained an expensive accessory in premium business cars - the electronics of that era were so demanding on amperage that none of the compact batteries could power it.
This continued until 1973, when the first truly portable cell phone Motorola appeared, later called the DynaTAC 8000X (went on sale only in 1983). The phone was content with a six-cell nickel-cadmium battery with a total capacity of 500 mAh. One charge was enough for 30-40 minutes of conversation (depending on the signal strength from the base station).
The charger for the DynaTAC 8000X had a trickle charging function - this is the supply of an already charged battery with low currents to compensate for its self-discharge, which is very much the sin of nickel-cadmium batteries. It took 10 hours to recharge the phone from scratch. For the hurried businessmen, Motorola offered a special fast charger - a 2kg docking station that could charge a DynaTAC 8000X battery in just an hour! At the same time, the phone almost did not heat up, and the battery did not degrade. In fact, fast charging of phones appeared not “yesterday”, but 37 years ago.
While in the first half of the 1990s mobile phones were developing new compact nickel-metal hydride batteries, a real revolution took place in the battery market: in 1991 Sony released the first lithium-ion battery that came with film camcorder CCD-TR1. Lithium-ion batteries outperformed their predecessors in terms of lifespan and energy density. In addition, they lacked the "memory effect", which finally gave the buyers of portable electronics the opportunity to recharge their equipment in a new way - without waiting for the battery to be completely discharged and without fully charging it.
With the advent of lithium-ion batteries, the standby time of phones has increased to days or even weeks, versus one or two days earlier. The era of "gluttonous" pocket personal computers (PDAs) and even more so smartphones had not yet arrived, so recharging the phone once a week was commonplace - there was simply no need for "fast" charging. But progress did not stand still, and in the late 1990s, lithium polymer batteries went on sale. The legendary 1999 Ericsson T28 became the first phone with a lithium polymer battery.
This was not a new type of battery, but just a small upgrade of lithium-ion cells: the liquid electrolyte in them was replaced with a solid or gel-like one, which increased the energy density. But the increased energy density made it possible to make thinner batteries with the same capacity. Or more capacious in the same size. The capacity of the batteries has increased markedly, but the charging speed has not changed. Most often, smartphones were bundled with the cheapest memory devices with an output power of about 5 W, which took up to three hours to replenish the charge of a capacious battery. Even if users bought adapters with a power of 10W, the smartphone power controller did not always agree to supply this amount of power to the battery, while remaining true to the safe 5V / 1A profile.The need to charge a smartphone for agonizingly long hours made the gears of progress move - in the early 2010s, mobile device manufacturers were actively looking for ways to quickly recharge batteries. And they did find it.
Fast charging: the future that has come
At the end of the twentieth century, it took on average one and a half to two hours to charge a phone, but mobile phones worked on a single charge for several days. A smartphone with a huge 2000 mAh battery capacity for the early 2010s could be set to zero in less than a day - thanks to demanding games, streaming video and fast mobile internet.
The so-called "slow" USB charging according to the USB Battery Charging standard allows the charger current to be increased to 2 A at 5 V, but even two hours to recharge a large smartphone is too long.
In 2012, the USB Power Delivery standard was adopted, which regulated the transmission of voltages up to 20 V and currents up to 5 A through the USB interface. However, high power requires high-quality certified cables. Based on the Power Delivery specifications, chip makers have begun to develop their own solutions for fast charging smartphones. Telecommunications giant Qualcomm, whose Quick Charge 2.0 protocol became an improved version of Power Delivery, was the first to do this - unlike the parent standard, Quick Charge 2.0 worked with any Micro-USB 2.0 cables and connectors.
The principle of operation of Quick Charge 2.0 consisted in the phased supply to the battery of an increased voltage up to 12 V at constant current until about half of the battery was charged. After that, the voltage drops and the charging speed decreases, which reduces overheating of the smartphone and the battery along with it.
Now the fifth version of Quick Charge is already relevant: Qualcomm promises to charge the smartphone up to 50% in 5 minutes and up to 100% in 15 minutes. This is because Quick Charge 5.0 provides for the transfer of power to a smartphone up to 100 watts. And without overheating the battery - the smartphone will warm up to no higher than 40 ° C.
Qualcomm Quick Charge is a proprietary licensed standard. It is supported only by systems-on-a Qualcomm Snapdragon chip, which, however, are built on about 40% of modern Android smartphones. Also Quick Charge must be supported by the charger. Adding Quick Charge to the PSU has only a minor impact on its price. Power supplies with this technology are necessarily marked with a lightning logo, and the charging port itself is highlighted in color.
Based on Quick Charge, other companies have developed their own, but fully compatible fast charging technologies: Motorola TurboPower, Xiaomi Mi Fast Charging, Samsung Adaptive Fast Charging, Asus BoostMaster and Vivo Dual-Engine Fast Charging. In fact, they are no different from Quick Charge except for the names, and therefore work perfectly in tandem with power supplies with Quick Charge support.
In contrast to charging with increased voltage, another approach deserved the right to life - charging batteries with increased currents at a normal voltage of 5 V. For example, the Chinese BBK Electronics, which owns the OPPO brand, took this path. VOOC technology (Voltage Open Loop Multi-step Constant-Current Charging) supplies a smartphone with a standard USB voltage of 5 V, but with a current of at least 4.0 A. The third version of VOOC brought support for currents up to 5.0 A, and the fourth version - up to 6.0 A. VOOC under different names came to smartphones of other BBK Electronics brands: OnePlus Dash Charge, Vivo Super FlashCharge and Realme Dart Charge.
The small 5W chargers that come with the iPhone are often left out of the box as unnecessary. The Anker PowerPort III Nano is similar in size and charges the iPhone with a maximum power of 18 watts. Source: Anker
VOOC and its analogs are paired with special batteries, divided into sectors. A battery with the support of this technology carries eight contact pads, through which several sectors of one battery are charged in parallel.
Since the charge voltage through VOOC is standard, the phone does not need to lower it to supply it to the battery, which means the controller will not lower it, releasing heat harmful to the battery. That is, in terms of battery health, VOOC is safer than Quick Charge. Another advantage turned out to be that when using the smartphone during VOOC charging, it does not overheat. But devices with Quick Charge up to version 5.0 are better not to be used during recharging, otherwise smartphones start to warm up and the power controller lowers the voltage and slows down charging for safety reasons.
VOOC looked too good until the user knew that the technology needed a special cable with thicker conductors to carry high currents and an additional signaling pin on the connector.
Anker PowerIQ — ,
As you can imagine, complete chargers for smartphones always support one fast charging technology (well, and its "copies"). If you are the proud owner of gadgets from different companies, for example, Apple iPad Pro with Power Delivery, Samsung GALAXY S9 with Adaptive Fast Charging, then charging from one gadget will charge another gadget in slow mode.
For a “zoo” of devices from different brands, it is useful to buy one universal adapter with multiple outputs for simultaneous charging of all gadgets - so that the charger understands what standard of fast charging the connected gadget works with and starts charging according to this standard.
In all Anker chargers, Anker PowerIQ technology is responsible for this. For example, the Anker PowerPort Atom III has USB-C and USB-A outputs, each marked with PowerIQ 3.0 and PowerIQ 2.0, respectively. These outputs can be used to connect smartphones, tablets and even laptops with support for USB Power Delivery, Qualcomm Quick Charge and their analogs - in all cases, the adapter will select the maximum allowable power mode, be it 5 V / 2.4 A, 9 V / 2 A or even 12 V / 1.5 A.
The Anker Powerport III Nano 20W can be an indispensable assistant in this case. It is the thinnest and lightest charger in the Anker range. The novelty will fit almost any Apple and Android device and eliminate the need to have a personal memory for each gadget. It features a single USB-C port capable of delivering up to 20W of power using the Power Delivery standard. Anker Innovations engineers fit 20W into an adapter measuring 2.74 x 3.00 cm, which is comparable to the size of a 5 ruble coin.
Every Anker charger with PowerIQ technology has a chip that communicates with the connected gadget and selects the most efficient power protocol for it. For example, PowerIQ 3.0 works with Power Delivery, Quick Charge, and Apple Fast Charging. When a smartphone is connected, the PowerIQ chip sends commands, with which it offers the smartphone in turn the supported power protocols. If the smartphone responds that it can work with Power Delivery or Quick Charge, the Anker charger transmits data on the supported output voltage and current. The smartphone will choose the optimal power supply mode from the proposed ones and send a command about it to the charger. After that, the Anker charger will adjust the voltage in accordance with the selected profile, and the smartphone will consume current in accordance with the protocol.
Several myths about battery charging
Smartphone users are still arguing on the Internet about the dangers of fast charging for batteries. Some point out that any deviation from the proven combination of 5 V / 2 A (10 W) over the years harms the battery, while others cite research results proving that supplying power to the phone even at 30 W, if it does affect the health of the battery, is extremely insignificant. ... We will now ruthlessly destroy this and a few more myths about charging batteries.
Of course, high charge and discharge currents are not good for batteries. But is it worth it to be afraid to charge the gadget in this way, or if the negative effect of this manifests itself, then towards the end of the life of the smartphone itself? Daily charging in the most gentle mode (5 V / 1 A) will reduce the capacity of the lithium polymer battery by about 10-15% over 400 cycles, which corresponds to one to one and a half years of using the device. After reaching 500 cycles, it is recommended to change the phone battery, since as it ages, the battery capacity does not drop linearly, but exponentially.
The effect of fast charging on battery wear was tested by specialists from the SLAC National Accelerator Laboratory (a laboratory at Stanford University) back in 2014. Research resultsshowed that the state of the anode and cathode does not change depending on the battery charging rate. In 2020, DDay.it employees staged a stress test for the OPPO Find X2 Pro smartphone with VOOC technology. Within a month and a half, the phone was charged with a 65 W adapter, during the test the battery survived 248 cycles. For a quick discharge, an artificial extreme load was created in the phone, from which the device heated up to a harmful 44 ° C. At the end of the experiment, the battery lost about 15% of its capacity, although it was initially assumed that the degradation would be up to 35%. If it were not for the high loads and the temperature dangerous for the battery, the drop in capacity would be even less.
It is surprising that even in 2020, among inexperienced smartphone users, there are long-standing myths about "correct" charging. For example, some people still “swing” the battery after buying a phone, charging the device to the end and discharging it to zero several times, as was recommended in the early 1990s for nickel-metal hydride cells. This supposedly helps to use the entire capacity of the new battery, and if this is not done, then the smartphone, they say, will be discharged earlier than it should. Someone also calls this process "calibrating the power controller."
In fact, lithium-ion batteries do not need any "training" before using the device, several full charge and discharge cycles will not affect the battery capacity at all and will not increase the possible battery life for a minute. The controller knows perfectly well what capacity it has to work with, and besides, sometimes it itself, without user intervention, calibrates as the battery degrades.
Legend about the importance of "swing" of batteries still feeds the myth of the memory effect. The memory effect itself, when the cell's capacity is lost due to frequent recharging of an incompletely discharged battery, really exists. Here are just the early lithium-ion and modern lithium-polymer batteries practically do not have this effect (its manifestation is negligible). Obsolete nickel-cadmium and, to a lesser extent, nickel-metal hydride batteries, which have not been used in gadgets since the late 1990s, are prone to memory effect.
The third myth says that smartphones cannot be left connected to a charger for a long time, for example, overnight - as if the battery is being overcharged beyond measure, which is why it loses its capacity and may even catch fire. In principle, in the early 1990s, such an opinion still had the right to exist, but now, in the era of lithium-ion batteries with controllers, it makes no difference at all how long you keep your smartphone connected to the outlet. Then the power controller was invented to prevent overcharging. When the battery is charged, the controller sees this and goes into charge-saving mode, reducing the current consumption to near-zero values.
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Over a quarter of a century, the capacity of mobile phone batteries has literally grown by an order of magnitude, as did the "appetites" of gadgets. Advances in battery technology are not moving as fast as in GPUs or memory, but today's lithium polymer batteries are a real miracle, requiring only quality power.
To unleash the full potential of the battery, enjoy safe and fast charging, you should choose a good charger - the bundled adapters of smartphones from economy often meet only the minimum requirements for charging. It is doubly smart to have a multiport universal charger at home that works with multiple fast charging protocols and has USB-A and USB-C outputs for the most modern and aging technology.