The first mobile phone that could carry, and not to carry on the machine was introduced by Motorola in 1983. The device weighed almost a kilo, and could only make calls. Today's smart phones - high-grade handheld computers, and "phone" functions are gradually losing relevance. Progress in this area is obvious, but few people think that no less an evolutionary way done and the batteries of mobile devices.
About the units
First of all it is necessary to clarify the article used in the units. Most of us are used to measure the energy of the battery cell in ampere-hours (Ah). This means that the battery capacity of 1 Ah or mAh 1000 can provide power with a current of 1 ampere hour. However, this unit does not include other important parameter - voltage that, depending on the model, the battery may be different. Therefore, to compare the battery is used watt-hours (Wh) battery capacity in Wh 1 (1 A * B * h) be able to issue a power of 1 watt per hour.
Nickel-cadmium (Ni-Cd) batteries
Motorola DynaTAC, in spite of their mobility, was too large and heavy to carry it in your pocket. Phones Motorola MicroTAC line 1989 in your pocket already placed. The first models were equipped with MicroTAC nickel-cadmium batteries, which could provide the devices to 90 minutes of talk time.
The cathode in the nickel-cadmium batteries made of nickel compounds with the addition of graphite powder, anode - of cadmium-containing compounds, and electrolyte - a mixture of potassium and lithium hydroxides.
Nickel-cadmium batteries have a number of advantages: a large charging current (and, as a result, little time is fully charged), long life (several thousand cycles), the ability to work in a wide range of temperatures, and they are not afraid of deep discharge. However, they have relatively low specific capacity (capacity per unit mass) - 45-65 Wh / kg and a high self-discharge capacity of about 10% per month. In addition, this type of battery is subject to the memory effect: when charging is not fully discharged its battery voltage decreases, which is interpreted by the majority of the charge controller, as the loss of capacity. These shortcomings have led to the fact that the phone manufacturers soon switched to a more advanced type of batteries.
Nickel-Metal Hydride (Ni-MH) batteries
Batteries of this type the cathode is made of nickel oxide anode - of various metal hydrides (usually nickel and lanthanum, or nickel, and lithium), and electrolyte - potassium hydroxide.
Unlike nickel-cadmium batteries, nickel metal hydride rechargeable batteries are less prone to the memory effect (it appears only if the charge is partially discharged battery, not to use a few days) and have a high specific capacity - 60-72 Wh / kg (in the same space capacity of approximately 20% higher as compared with nickel-cadmium batteries). Furthermore, unlike the Ni-Cd, Ni-MH batteries are environmentally friendly. But they also have drawbacks, chief among them - even higher self-discharge, about 10% of the first day, followed by 0.5% every day. The service life of such batteries is about 200-500 cycles and operating temperature range is relatively narrow: at -20 ° C batteries lose up to 30% capacity. Most of these shortcomings was overcome only in 2005, when they began to be issued NiMH batteries with low self-discharge (LSD Ni-MH). Despite this, as well as nickel-cadmium, nickel-metal hydride batteries are prone to memory effect. The first Ni-MH batteries used in phones Motorola MicroTAC to replace Ni-Cd, had a capacity of about 7.2 Wh and can provide phone about 2 hours of battery life in talk mode.
Smartphones with Ni-MH batteries continued to be issued until the end of the XX century. By that time, the battery life of devices has increased, but still not too impressed. Released in 1999, Siemens C25 battery has a capacity of 2.34 Wh and could work about 5 hours of talk time, while the legendary Nokia 3310, which appeared in 2000, despite the large battery capacity of 3.24 Wh could hold only about 3-4 hours.
However, Nokia 3310 was produced from Ni-MH batteries is relatively short-lived: the new revision of this model even comes with lithium-ion batteries.
Lithium-ion (Li-Ion) battery
Lithium-ion batteries were first released by Sony in 1991. Thanks to its balanced quality, they remain the most popular type of batteries in mobile devices today.
The anode and cathode in a lithium-ion batteries use aluminum and copper foil, respectively, coated with various materials. Charge carriers are the lithium ions. In the first lithium-ion battery as the anode material of lithium was used that the frequent charge-discharge lead to the growth of the sponge-like structure of the metal - dendrites. This could lead to the closure of the electrodes, causing explosions and fire. The problem was solved by the use of graphite instead of lithium. As for the cathode material, now in batteries for portable equipment are used as a lithium compound, the manganese and oxygen, as well as lithium cobaltate.
One of the first phone, use lithium-ion batteries, has been Motorola MicroTAC 8700, in which the batteries of this type is available as an option instead of the standard nickel-metal hydride. Reading this article, you might think that in addition to Motorola phones from other manufacturers at the time did not exist, and it is far from the truth: the company has been the market leader and, quite naturally, one of the first to introduce new technologies. MicroTAC 8700 was released in 1996 and the talk time can work about 3.5 hours. A typical battery capacity at that time was 700-800 mAh and their specific capacity was only about 100 Wh / kg.
Since 2001, the use of lithium-ion batteries becomes massive, and other types of fade into the background. The battery life of devices with lithium-ion batteries were already considerably more long: Ericsson T68 battery with 3.42 Wh could work out talk time up to 11 hours, and the Motorola RAZR V3 battery with 2.52 Wh - up to 7 hours.
Even then, phones began to appear, "sharpened" under a long battery life. Models Philips 9 @ 9 from the line of Xenium, still exists today, was the battery capacity 3.1 Wh. Hours of talk was typical for that time - about 7.5 hours, but in standby mode, the phone could last up to a month. For comparison, Ericsson T68 «living» only 12 days.
Around the same time began to spread PDA operating systems PalmOS and Pocket PC (which was later renamed as Windows Mobile).The first Palm handhelds with built-in rechargeable battery has become Palm V lithium-ion battery with a capacity of 2.4 Wh. Feedback from users of the time required to charge the gadget of all time in 5 days at a sufficiently active use. In the sale of the gadget was released in 1999.
The relatively large battery life was due to the use of devices of monochrome screens and relatively weak by modern standards toppings. For example, the PDA Tungsten T3, which appeared in 2003, had quite a powerful processor and a color display, and battery capacity 3.7 Wh sufficient only for 3.5 hours of surfing using a Bluetooth-connection to the phone.
This shortcoming was corrected in the released in 2004, Tungsten T5, battery capacity which was already 5 Wh and battery life with continuous use - about 5 hours. But this was not enough, which is why many owners of these devices use the program to reduce the frequency of the processor, which allowed for a few hours to extend the time of their work.
Slightly better things were under control at the CCP's mobile operating system from Microsoft, for example, Compaq iPAQ 3760 on the Pocket PC 2002. The device appeared in 2001 and, although he had the battery is only 3.5 Wh could work out in continuous use up to 7 hours.
One of the first smartphones on the Microsoft platform has become Qtek 1020, also known as the HTC Wallaby. The device was released in 2002 and runs on the Pocket PC 2002, and its battery capacity was 5.55 Wh. Talk device worked relatively few - 3.5 hours, but it was a fee for the broad functions of a pocket computer.
One of the most popular smartphones due time became available under a variety of brand HTC Universal with a physical QWERTY-keyboard. He was 6 Wh battery, which allows the unit to work in the talk mode up to 8 hours. The device was released in 2005 and runs on Windows Mobile 5.0.
As for communicators PalmOS (by then already the fifth version), the typical representative of this family, released in 2006, Palm Treo 700p, had to 6,66 Wh battery. Talk this gadget could work for about 4.5 hours.
Communicators used to be called and the device to the undeservedly forgotten today, the platform Symbian OS. Launched in 2006, Nokia N73 on Symbian OS 9.1 had a capacity of 4 Wh battery and talk time up to 6 hours.
Modern lithium-ion batteries have a specific capacity of up to 240 Wh / kg, the service life of about 600 cycles and have minimal self-discharge - about 3% per month. However, to keep such batteries should be charged no more than half full, otherwise it will lead to a reduction in their lifetime. Currently, the smartphone uses lithium-ion batteries with a capacity to 12.2 Wh and above. For example, Samsung Galaxy S6 with 9.4 Wh battery can work in talk mode about 17 hours.
The modern history of the smartphone can be counted since 2007, when he appeared Apple iPhone, which became the first mass phone with a capacitive screen. He had a lithium-polymer battery with 5.18 Wh and worked in talk time up to 8 hours.
Despite the fact that the autonomy of the smartphone (at least talk) has steadily increased, the strap for tablets in 10 hours with almost any mode of use was given by Apple even with the release of the first model iPad. Since then, the majority of high-quality tablets of large companies have approximately the same autonomy.
Despite the impressive time of talk, when mixed use modern smartphones rarely live more than a day or two. Because of this, some performance release device with batteries huge by the standards of this class of device capacity. One example - Philips Xenium V526 battery with 18.5 Wh, which can run up to 47 days of standby time or up to 28 hours of talk time. The smartphone was released in 2015 and works on Android 5.1.
For a long time it was thought that the lithium-ion batteries are not subject to the memory effect, but in 2013, scientists have discovered that it can still be observed in a large number of frequent partial discharge cycles and charge. The reason lies in the capture of the lithium ions at the cathode surface, which prevent other ions carry the charge within the battery. In addition, the lithium-ion battery is contraindicated in deep discharge, which can completely damage the battery.
Lithium-Polymer (Li-Po) batteries
By design, the lithium-polymer batteries like lithium ion, but as the electrolyte used in these polymeric materials capable of conducting lithium ions. The advantage of this design is the ability to do the batteries of any shape, including flexible, no memory effect and a slightly higher specific capacity.
Established disadvantages of lithium-ion batteries are also characteristic of the lithium-polymer - a relatively short service life and intolerance to deep discharge.
It is not known in which the smartphone and the phone was first used lithium polymer battery, but one of the first companies to apply the mass smartphone battery irregular shape became LG. South Korean manufacturers managed to fit in a relatively small body of the smartphone LG G2 battery with a capacity of 11.4 Wh.
But if the smart phone market lithium-polymer batteries still continue to win, among devices such as quadrocopters, they are, in fact, have become standard due to the high capacity udёlnoy. For example, the popular copter DJI Phantom 3 has a removable battery capacity of 68 Wh, which gives it about 23 minutes of flight.
Charge Technology
Over time, developed not only batteries, but also the technology of their charge. Before the batteries are not suited for high current charge, so in most chargers use a voltage of 5 volts and a current of 0.5 amperes. Over the past few years, these parameters gradually increased, and the main merit in promoting the rapid charging probably belongs company Qualcomm. Its technology Quick Charge 3.0 uses a voltage up to 20 V and current up to 3 A (these parameters can be changed during the charging process to achieve the best results and to save battery life). Power chargers with support for Quick Charge 3.0 is 18 watts, which allows you to fully charge the battery for a typical smart phone less than an hour. While the technology is just getting ready to hit the market in 2016, Quick Charge 2.0 has already been successfully used in smartphones like LG G4, Samsung Galaxy S6 and Note 5, HTC One M9, Sony Xperia Z5 and YotaPhone 2.
In addition to fast charging, appeared relatively recently and wireless charging technologies. One of the most common standards today - Qi. His work is based on energy transfer over short distances (up to four centimeters) between the two coils by electromagnetic induction. In addition to power transmission standard provides for the exchange of information between mobile device and base station - determination of the best parameters for the charging and position relative to the base station of the gadget. Wireless charging can also be fast: if the first Qi-compatible devices received from the base station 400-600 mA current strength, it now can be more than 1000 mA. This technology is used in the latest smartphones, Samsung, and can fully charge a smartphone in less than two hours.
Future batteries
Despite the fact that over 30 years the mobile device battery seriously improved, much remains to be improved. Currently, research is being conducted on several fronts: increasing the velocity of the charge, the life and the specific capacity.
One of the most promising developments - aluminum ion (Al-Ion) battery, proposed by scientists at Stanford University. As a cathode in such batteries will be used graphite as an anode - aluminum. Two key advantages of the new type of battery - long life (at least 7,500 cycles without loss of capacity) and the ability to charge very high currents, which in theory would allow gadgets to charge for a few seconds.
Another type of battery operation which has already been confirmed in scientific research - lithium-air. The principle of operation of such batteries is the release of energy in the oxidation of lithium with oxygen, which is taken from the normal air. Lithium-air batteries have great specific capacity - more than 500 Wh / kg, but the first samples have not worked for more than 10 cycles. The fact that in addition to the main battery discharge reaction product - lithium oxide, which is reduced to oxygen and metallic lithium during the charge - and the formed byproduct, lithium carbide. The reason for this was the use of a graphite anode like the lithium-ion batteries. A few years ago the problem was solved by replacing the graphite to titanium carbide, Now lithium-air batteries can work out 100 cycles, losing only about 2% of the original capacity. Now scientists continue to work on increasing the service life and operating temperature range for these batteries.
Perhaps one should not expect that in the next year or even next year will happen revolution in the world of batteries, but that is exactly what to expect - a gradual improvement in their parameters and, consequently, increasing the operating time of our gadgets.
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