How to properly charge a lithium-ion battery and why is it even needed? Our modern devices operate thanks to the presence of autonomous power supplies. And it doesn’t matter what kind of devices they are: electric smartphones or laptops. This is why it is so important to know the answer to the question of how to properly charge a lithium-ion battery.

A little about what a lithium-ion battery is

Autonomous power supplies, which are used in modern smartphones and other devices, are usually divided into several different groups. There are quite a lot of them. Take the same ones. But it is in portable equipment, that is, in smartphones and laptops, that lithium-ion batteries (English designation Li-Ion) are most often installed. The reasons that led to this are of different nature.

The advantages of these types of batteries

The first thing to note is how simple and cheap it is to produce these energy sources. Their additional advantages are excellent operating characteristics. Self-discharge losses are a very small indicator, and this also played a role. But the supply of cycles for charging and discharging is very, very large. Together, all this makes lithium-ion batteries leaders among other similar devices in the field of their use in smartphones and laptops. Although exceptions to the rule exist, they account for about 10 percent of the total number of cases. That is why many users ask the question of how to properly charge a lithium-ion battery.

Important and interesting facts

A smartphone battery has its own specific features. Therefore, you need to know certain rules and be familiar with the relevant instructions before you begin the process of forced charging or discharging. It should be noted first of all that most batteries of this type are specially equipped with an additional monitoring device. Its use is determined by the need to maintain the charge at a certain level (also called critical). Thus, the control device, built into, among other things, the battery for a smartphone, does not allow us to cross that fatal line, after which the battery simply “dies,” as service specialists like to say. From the point of view of physics, everything looks like this: during the reverse process (critical discharge), the voltage of the lithium-ion battery simply drops to zero. At the same time, the flow of current is blocked.

How to properly charge digital equipment based on this source of battery life

If your smartphone is powered by a lithium-ion battery, then the device itself must be charged when the battery indicator shows approximately the following numbers: 10-20 percent. The same is true for phablets and tablet computers. This is a short answer to the question of how to properly charge a lithium-ion battery. It should be added that even when reaching 100 percent rated charge, the device must be kept connected to the electrical network for another one to two hours. The fact is that the devices interpret charging incorrectly, and the 100 percent that a smartphone or tablet gives is in fact no more than 70-80 percent.

If your device is equipped with a lithium-ion battery, you should know some of the intricacies of its operation. This will be very useful in the future, because by following them you can extend the life of not only this element, but the entire device as a whole. So, remember, once every three months you need to completely discharge the device. This is done for preventive purposes.

But we’ll talk about how to charge a discharged battery later. For now, we’ll just point out that a desktop computer and laptop are not capable of providing a sufficiently high voltage when connecting a mobile device to these technological wonders via a USB standard port. Accordingly, in order to fully charge the device from these sources, it will take more time. Interestingly, one technique can extend the life of a lithium-ion battery. It consists of alternating charging cycles. That is, once you charge the device completely, 100 percent, the second time - not completely (80 - 90 percent). And these two options alternate in turn. In this case, it can be used for lithium-ion batteries.

Terms of use

In general, lithium-ion power supplies can be called unpretentious. We have already talked about this topic and found out that this characteristic, along with others, has become the reason for their widespread use in computing. However, even such a smart battery architecture does not fully guarantee their long-term performance. This period depends primarily on the person. But we are not required to do anything out of the ordinary. If there are five simple rules that we can remember forever, apply them successfully. In this case, the lithium-ion power supply will serve you for a very, very long time.

Rule one

It lies in the fact that it is not necessary completely. It has already been said that such a procedure should be carried out only once every three months. Modern designs of these power supplies do not have a “memory effect”. Actually, that’s why it’s better to have time to charge the device before it completely runs out. By the way, it is quite noteworthy that some manufacturers of relevant products measure the service life of products in the number of cycles. High-end products can “survive” about six hundred cycles.

Rule two

It states that the mobile device needs to be completely discharged. It should be carried out once every three months for preventive purposes. On the contrary, irregular and unstable charging can shift the nominal minimum and maximum charge marks. Thus, the device into which this source of autonomous operation is built begins to receive false information about how much energy actually remains. And this, in turn, leads to incorrect calculations of energy consumption.

Prophylactic discharge is designed to prevent this. When this happens, the control circuit will automatically reset the minimum charge value. However, there are some tricks here. For example, after a complete discharge, it is necessary to “fill in” the power source, holding it for an additional 12 hours. Apart from an ordinary electrical network and a wire, we don’t need anything else for charging in this matter. But the operation of the battery after a preventive discharge will become more stable, and you will be able to immediately notice it.

Rule three

If you don't use your battery, you still need to monitor its condition. At the same time, the temperature in the room where you store it should preferably be no more and no less than 15 degrees. It is clear that it is not always possible to achieve exactly this figure, but still, the smaller the deviation from this value, the better it will be. It should be noted that the battery itself must be charged 30-50 percent. Such conditions will allow you to maintain the power source for a long time without serious damage. Why shouldn't it be fully charged? But because a “full to capacity” battery, due to physical processes, loses quite a large part of its capacity. If the power source is stored for a long time in a discharged state, then it becomes practically useless. And the only place where it will really be useful is in the trash. The only way, although unlikely, is to remanufacture lithium-ion batteries.

Rule four

The price of which ranges from several hundred to several thousand rubles, should be charged only using original devices. This applies to a lesser extent to mobile devices, since adapters are already included in their package (if you buy them from the official store). But in this case they only stabilize the supplied voltage, and the charger, in fact, is already built into your device. Which, by the way, cannot be said about video cameras and cameras. This is exactly what we are talking about, here the use of third-party devices when charging batteries can cause noticeable harm.

Rule five

Monitor the temperature. Lithium-ion batteries can withstand heat stress, but overheating is detrimental to them. And low temperatures for a power source are not the best that can happen. Although the greatest danger comes precisely from the process of overheating. Remember that the battery should not be exposed to direct sunlight. The range of temperatures and their permissible values ​​starts at - 40 degrees and ends at + 50 degrees Celsius.

Reading “tips for operating” batteries on forums, you can’t help but think - either people skipped physics and chemistry at school, or they think that the rules for operating lead-acid and ion batteries are the same.
Let's start with the principles of operation of a Li-Ion battery. On the fingers, everything is extremely simple - there is a negative electrode (usually made of copper), there is a positive one (made of aluminum), between them there is a porous substance (separator) impregnated with electrolyte (it prevents the “unauthorized” transfer of lithium ions between the electrodes):

The principle of operation is based on the ability of lithium ions to be integrated into the crystal lattice of various materials - usually graphite or silicon oxide - with the formation of chemical bonds: accordingly, when charging, the ions are built into the crystal lattice, thereby accumulating a charge on one electrode, and when discharging, they respectively move back to another electrode , giving away the electron we need (who is interested in a more accurate explanation of the processes taking place - google intercalation). Water-containing solutions that do not contain a free proton and are stable over a wide voltage range are used as electrolytes. As you can see, in modern batteries everything is done quite safely - there is no lithium metal, there is nothing to explode, only ions run through the separator.
Now that everything has become more or less clear about the operating principle, let’s move on to the most common myths about Li-Ion batteries:

1. Myth one. The Li-Ion battery in the device cannot be discharged to zero percent.
   In fact, everything sounds correct and is consistent with physics - when discharged to ~2.5 V, the Li-Ion battery begins to degrade very quickly, and even one such discharge can significantly (up to 10%!) reduce its capacity. In addition, if the voltage is discharged to such a voltage with a standard charger, it will no longer be possible to charge it - if the battery cell voltage drops below ~3 V, the “smart” controller will turn it off as damaged, and if there are all such cells, the battery can be taken to the trash.
   But there is one very important thing that everyone forgets: in phones, tablets and other mobile devices, the operating voltage range on the battery is 3.5-4.2 V. When the voltage drops below 3.5 V, the indicator shows zero percent charge and the device turns off, but before " critical" 2.5 V is still very far away. This is confirmed by the fact that if you connect an LED to such a “discharged” battery, it can remain on for a long time (maybe someone remembers that they used to sell phones with flashlights that were turned on by a button regardless of the system. So the light there continued to burn even after discharge and turn off the phone). That is, as you can see, during normal use, discharge to 2.5 V does not occur, which means it is quite possible to discharge the battery to zero percent.
2. Myth two. If Li-Ion batteries are damaged, they explode.
   We all remember the “explosive” Samsung Galaxy Note 7. However, this is rather an exception to the rule - yes, lithium is a very active metal, and it is not difficult to explode it in the air (and it burns very brightly in water). However, modern batteries do not use lithium, but its ions, which are much less active. So for an explosion to occur, you need to try very hard - either physically damage the charging battery (cause a short circuit), or charge it with a very high voltage (then it will be damaged, but most likely the controller will simply burn out itself and will not allow the battery to charge). Therefore, if you suddenly have a damaged or smoking battery in your hands, don’t throw it on the table and run away from the room shouting “we’re all going to die” - just put it in a metal container and take it out to the balcony (so as not to breathe in the chemicals) - the battery will smolder for some time and then go out. The main thing is not to fill it with water, the ions are of course less active than lithium, but still a certain amount of hydrogen will also be released when reacting with water (and it likes to explode).
3. Myth three. When a Li-Ion battery reaches 300 (500/700/1000/100500) cycles, it becomes unsafe and needs to be changed urgently.
   A myth, fortunately, that circulates less and less on forums and has no physical or chemical explanation at all. Yes, during operation, the electrodes oxidize and corrode, which reduces the battery capacity, but this does not threaten you with anything other than shorter battery life and unstable behavior at 10-20% charge.
4. Myth four. Li-Ion batteries cannot be used in the cold.
   This is more of a recommendation than a prohibition. Many manufacturers prohibit the use of phones at sub-zero temperatures, and many have experienced rapid discharge and even shutdown of phones in the cold. The explanation for this is very simple: the electrolyte is a water-containing gel, and everyone knows what happens to water at subzero temperatures (yes, it freezes, if anything), thereby rendering some area of ​​the battery unusable. This leads to a voltage drop, and the controller begins to consider this a discharge. This is not good for the battery, but it is not fatal either (after heating, the capacity will return), so if you desperately need to use the phone in the cold (to use it - take it out of a warm pocket, check the time and put it back does not count) then it is better to charge it 100% and turn on any process that loads the processor - this will cool it down more slowly.
5. Myth fifth. A swollen Li-Ion battery is dangerous and should be thrown away immediately.
   This is not exactly a myth, but rather a precaution - a swollen battery can simply burst. From a chemical point of view, everything is simple: during the intercalation process, the electrodes and electrolyte decompose, resulting in the release of gas (it can also be released during recharging, but more on that below). But very little of it is released, and for the battery to appear swollen, several hundred (if not thousands) of recharge cycles must go through (unless, of course, it is defective). There are no problems getting rid of gas - just pierce the valve (in some batteries it opens itself when there is excess pressure) and bleed it off (I don’t recommend breathing with it), after which you can cover the hole with epoxy resin. Of course, this will not return the battery to its former capacity, but at least now it will definitely not burst.
6. Myth six. Overcharging is harmful to Li-Ion batteries.
   But this is no longer a myth, but a harsh reality - when recharging, there is a high chance that the battery will swell, burst and catch fire - believe me, there is little pleasure in being splashed with boiling electrolyte. Therefore, all batteries have controllers that simply prevent the battery from being charged above a certain voltage. But here you need to be extremely careful in choosing a battery - Chinese handicraft controllers can often malfunction, and I don’t think fireworks from your phone at 3 am will make you happy. Of course, the same problem exists in branded batteries, but firstly, this happens much less often there, and secondly, they will replace your entire phone under warranty. This myth usually gives rise to the following:
7. Myth seventh. When you reach 100%, you need to remove the phone from charging.
   From the sixth myth, this seems reasonable, but in reality there is no point in getting up in the middle of the night and unplugging the device: firstly, controller failures are extremely rare, and secondly, even when the indicator reaches 100%, the battery still charges for some time to the very, very maximum low currents, which adds another 1-3% capacity. So, in reality, you shouldn’t play it safe.
8. Myth eight. You can charge the device only with the original charger.
   The myth exists due to the poor quality of Chinese chargers - at a normal voltage of 5 +- 5% volts they can produce both 6 and 7 - the controller, of course, will smooth out this voltage for some time, but in the future it will, at best, lead to to the controller burning out, at worst - to an explosion and (or) failure of the motherboard. The opposite also happens - under load, the Chinese charger produces 3-4 volts: this will lead to the battery not being able to charge completely.

Modern mobile phones, laptops, and tablets use lithium-ion batteries. They gradually replaced alkaline batteries from the portable electronics market. Previously, all of these devices used nickel-cadmium and nickel-metal hydride batteries. But their days are over, since Li─Ion batteries have better characteristics. True, they cannot replace alkaline ones in all respects. For example, the currents that nickel-cadmium batteries can produce are unattainable for them. This is not critical for powering smartphones and tablets. However, in the field of portable power tools that draw a lot of current, alkaline batteries are still the way to go. However, work on developing batteries with high discharge currents without cadmium continues. Today we will talk about lithium-ion batteries, their design, operation and development prospects.

The very first battery cells with a lithium anode were released in the seventies of the last century. They had a high specific energy intensity, which immediately made them in demand. Experts have long sought to develop a source based on an alkali metal that has high activity. Thanks to this, the high voltage of this type of battery and energy density were achieved. At the same time, the development of the design of such elements was completed quite quickly, but their practical use caused difficulties. They were dealt with only in the 90s of the last century.

This happened after a series of accidents. At the time of the conversation, the current consumed from the battery reached its maximum and ventilation began with the emission of flames. As a result, there have been many cases of users suffering facial burns. Therefore, scientists had to refine the design of lithium-ion batteries.

Lithium metal is extremely unstable, especially when charging and discharging. Therefore, researchers began to create a lithium-type battery without using lithium. Ions of this alkali metal began to be used. This is where their name comes from.

Lithium ion batteries have a lower energy density than . But they are safe if charge and discharge standards are observed.

Reactions occurring in a Li─Ion battery

A breakthrough in the direction of introducing lithium-ion batteries into consumer electronics was the development of batteries in which the negative electrode was made of carbon material. The carbon crystal lattice was very suitable as a matrix for the intercalation of lithium ions. To increase the battery voltage, the positive electrode was made of cobalt oxide. The potential of lite cobalt oxide is approximately 4 volts.

The operating voltage of most lithium-ion batteries is 3 volts or more. During the discharge process at the negative electrode, lithium is deintercalated from carbon and intercalated into cobalt oxide of the positive electrode. During the charging process, the processes occur in reverse. It turns out that there is no metallic lithium in the system, but its ions work, moving from one electrode to another, creating an electric current.

Reactions on the negative electrode

All modern commercial models of lithium-ion batteries have a negative electrode made of carbon-containing material. The complex process of intercalation of lithium into carbon largely depends on the nature of this material, as well as the substance of the electrolyte. The carbon matrix on the anode has a layered structure. The structure can be ordered (natural or synthetic graphite) or partially ordered (coke, soot, etc.).

During intercalation, lithium ions push the carbon layers apart, inserting themselves between them. Various intercalates are obtained. During intercalation and deintercalation, the specific volume of the carbon matrix changes insignificantly. In addition to carbon material, silver, tin and their alloys can be used in the negative electrode. They are also trying to use composite materials with silicon, tin sulfides, cobalt compounds, etc.

Reactions on the positive electrode

Primary lithium cells (batteries) often use a variety of materials to make the positive electrode. This cannot be done in batteries and the choice of material is limited. Therefore, the positive electrode of a Li─Ion battery is made of lithiated nickel or cobalt oxide. Lithium manganese spinels can also be used.

Research is currently underway on mixed phosphate or mixed oxide materials for the cathode. As experts have proven, such materials improve the electrical characteristics of lithium-ion batteries. Methods for applying oxides to the cathode surface are also being developed.

The reactions that occur in a lithium-ion battery during charging can be described by the following equations:

positive electrode

LiCoO 2 → Li 1-x CoO 2 + xLi + + xe -

negative electrode

С + xLi + + xe — → CLi x

During the discharge process, reactions go in the opposite direction.

The figure below schematically shows the processes occurring in a lithium-ion battery during charging and discharging.

Lithium-ion battery design

According to their design, Li─Ion batteries are made in cylindrical and prismatic designs. The cylindrical design represents a roll of electrodes with separator material to separate the electrodes. This roll is placed in a housing made of aluminum or steel. The negative electrode is connected to it.

The positive contact is output in the form of a contact pad at the end of the battery.

Li-Ion batteries with a prismatic design are made by stacking rectangular plates on top of each other. Such batteries make it possible to make the packaging more dense. The difficulty lies in maintaining the compressive force on the electrodes. There are prismatic batteries with a roll assembly of electrodes twisted into a spiral.

The design of any lithium-ion battery includes measures to ensure its safe operation. This primarily concerns the prevention of heating and ignition. A mechanism is installed under the battery cover that increases the resistance of the battery as the temperature coefficient increases. When the pressure inside the battery increases above the permissible limit, the mechanism breaks the positive terminal and the cathode.

In addition, to increase operating safety, Li-Ion batteries must use an electronic board. Its purpose is to control the charge and discharge processes, to prevent overheating and short circuits.

There are many prismatic lithium-ion batteries currently being produced. They find application in smartphones and tablets. The design of prismatic batteries can often differ between different manufacturers, since they do not have a single unification. Electrodes of opposite polarity are separated by a separator. For its production, porous polypropylene is used.

The design of Li-Ion and other types of lithium batteries is always sealed. This is a mandatory requirement, since leakage of electrolyte is not allowed. If it leaks, the electronics will be damaged. In addition, the sealed design prevents water and oxygen from entering the battery. If they get inside, they will destroy the battery as a result of a reaction with the electrolyte and electrodes. The production of components for lithium batteries and their assembly takes place in special dry boxes in an argon atmosphere. In this case, complex techniques of welding, sealing, etc. are used.

As for the amount of active mass of a Li-Ion battery, manufacturers are always looking for a compromise. They need to achieve maximum capacity and ensure safe operation. The following relation is taken as a basis:

A o / A p = 1.1, where

A o – active mass of the negative electrode;

And n is the active mass of the positive electrode.

This balance prevents the formation of lithium (pure metal) and prevents fire.

Parameters of Li-Ion batteries

Lithium-ion batteries produced today have a high specific energy capacity and operating voltage. The latter is in most cases between 3.5 and 3.7 volts. Energy intensity ranges from 100 to 180 watt-hours per kilogram or 250 to 400 per liter. Some time ago, manufacturers could not produce batteries with a capacity higher than several ampere-hours. Now the problems hindering development in this direction have been eliminated. So, lithium batteries with a capacity of several hundred ampere-hours began to be found on sale.

The discharge current of modern Li─Ion batteries ranges from 2C to 20C. They operate in the ambient temperature range from -20 to +60 Celsius. There are models that are operational at -40 Celsius. But it’s worth saying right away that special battery series work at subzero temperatures. Conventional lithium-ion batteries for mobile phones become inoperable at subzero temperatures.

The self-discharge of this type of battery is 4-6 percent during the first month. Then it decreases and amounts to a percentage per year. This is significantly less than that of nickel-cadmium and nickel-metal hydride batteries. Service life is approximately 400-500 charge-discharge cycles.

Now let's talk about the operating features of lithium-ion batteries.

Operation of lithium-ion batteries

Charging Li─Ion batteries

The charge of lithium-ion batteries is usually combined. First, they are charged at a constant current of 0.2-1C until they reach a voltage of 4.1-4.2 volts. And then charging is carried out at a constant voltage. The first stage lasts about an hour, and the second about two. To charge the battery faster, pulse mode is used. Initially, Li-Ion batteries with graphite were produced and a voltage limit of 4.1 volts per cell was set for them. The fact is that at a higher voltage in the element, side reactions began, shortening the life of these batteries.

Gradually, these disadvantages were eliminated by doping graphite with various additives. Modern lithium-ion cells charge up to 4.2 volts without any problems. The error is 0.05 volts per element. There are groups of Li─Ion batteries for the military and industrial sectors, where increased reliability and long service life are required. For such batteries, the maximum voltage per cell is 3.90 volts. They have a slightly lower energy density, but an increased service life.

If you charge a lithium-ion battery with a current of 1C, then the time to fully gain capacity will be 2-3 hours. The battery is considered fully charged when the voltage increases to maximum and the current decreases to 3 percent of the value at the beginning of the charging process. This can be seen in the graph below.

The graph below shows the stages of charging a Li─Ion battery.

The charging process consists of the following steps:

• Stage 1. At this stage, maximum charging current flows through the battery. It continues until the threshold voltage is reached;
• Stage 2. At a constant voltage on the battery, the charging current gradually decreases. This stage stops when the current decreases to 3 percent of the initial value;
• Stage 3. If the battery is stored, then at this stage there is a periodic charge to compensate for self-discharge. This is done approximately every 500 hours.
  It is known from practice that increasing the charge current does not reduce the battery charging time. As the current increases, the voltage rises faster to the threshold value. But then the second charging stage lasts longer. Some chargers (chargers) can charge a Li─Ion battery in an hour. In such chargers there is no second stage, but in reality the battery at this point is charged by about 70 percent.

As for jet charging, it is not applicable for lithium-ion batteries. This is explained by the fact that this type of battery cannot absorb excess energy when recharging. Jet charging can lead to the transition of some lithium ions to the metallic state (valency 0).

A short charge well compensates for self-discharge and loss of electrical energy. Charging in the third stage can be done every 500 hours. As a rule, it is performed when the battery voltage is reduced to 4.05 volts on one element. The charge is carried out until the voltage rises to 4.2 volts.

It is worth noting the poor resistance of lithium-ion batteries to overcharging. As a result of the supply of excess charge on the carbon matrix (negative electrode), deposition of metallic lithium may begin. It has very high chemical activity and interacts with the electrolyte. As a result, the release of oxygen begins at the cathode, which threatens an increase in pressure in the housing and depressurization. Therefore, if you charge a Li─Ion element bypassing the controller, do not allow the charging voltage to rise higher than what the battery manufacturer recommends. If you constantly recharge the battery, its service life will be shortened.

Manufacturers pay serious attention to the safety of Li-Ion batteries. Charging stops when the voltage increases above the permissible level. A mechanism is also installed to turn off the charge when the battery temperature rises above 90 Celsius. Some modern battery models have a mechanical switch in their design. It is triggered when pressure increases inside the battery housing. The voltage control mechanism of the electronic board disconnects the can from the outside world based on the minimum and maximum voltage.

There are lithium-ion batteries without protection. These are models containing manganese. When recharged, this element helps inhibit lithium metallization and release of oxygen. Therefore, protection is no longer needed in such batteries.

Storage and discharge characteristics of lithium-ion batteries

Lithium batteries are stored quite well and self-discharge per year is only 10-20%, depending on storage conditions. But at the same time, degradation of battery cells continues even if it is not used. In general, all electrical parameters of a lithium-ion battery may differ for each specific instance.

For example, the voltage during discharge changes depending on the degree of charging, current, ambient temperature, etc. The service life of the battery is influenced by the currents and modes of the discharge-charge cycle and temperature. One of the main disadvantages of Li-Ion batteries is their sensitivity to charge-discharge mode, which is why they provide many different types of protection.

The graphs below show the discharge characteristics of lithium-ion batteries. They examine the dependence of voltage on discharge current and ambient temperature.

As you can see, as the discharge current increases, the drop in capacity is insignificant. But at the same time, the operating voltage decreases noticeably. A similar picture is observed at temperatures less than 10 degrees Celsius. It is also worth noting the initial drop in battery voltage.

Lithium-ion batteries are not as finicky as their nickel-metal hydride counterparts, but they still require some care. Sticking to five simple rules, you can not only extend the life cycle of lithium-ion batteries, but also increase the operating time of mobile devices without recharging.

Do not allow complete discharge. Lithium-ion batteries do not have the so-called memory effect, so they can and, moreover, need to be charged without waiting for them to discharge to zero. Many manufacturers calculate the life of a lithium-ion battery by the number of full discharge cycles (up to 0%). For quality batteries this 400-600 cycles. To extend the life of your lithium-ion battery, charge your phone more often. Optimally, as soon as the battery charge drops below 10-20 percent, you can put the phone on charge. This will increase the number of discharge cycles to 1000-1100 .
Experts describe this process with such an indicator as Depth Of Discharge. If your phone is discharged to 20%, then the Depth of Discharge is 80%. The table below shows the dependence of the number of discharge cycles of a lithium-ion battery on the Depth of Discharge:

Discharge once every 3 months. Fully charging for a long time is just as harmful to lithium-ion batteries as constantly discharging to zero.
Due to the extremely unstable charging process (we often charge the phone as needed, and wherever possible, from USB, from a socket, from an external battery, etc.), experts recommend completely discharging the battery once every 3 months and then charging it to 100% and holding it on charge 8-12 hours. This helps reset the so-called high and low battery flags. You can read more about this.

Store partially charged. The optimal condition for long-term storage of a lithium-ion battery is between 30 and 50 percent charge at 15°C. If you leave the battery fully charged, its capacity will decrease significantly over time. But the battery, which has been collecting dust on a shelf for a long time, discharged to zero, is most likely no longer alive - it’s time to send it for recycling.
The table below shows how much capacity remains in a lithium-ion battery depending on storage temperature and charge level when stored for 1 year.

Use the original charger. Few people know that in most cases the charger is built directly inside mobile devices, and the external network adapter only lowers the voltage and rectifies the current of the household electrical network, that is, it does not directly affect the battery. Some gadgets, such as digital cameras, do not have a built-in charger, and therefore their lithium-ion batteries are inserted into an external “charger”. This is where using an external charger of questionable quality instead of the original one can negatively affect the performance of the battery.

Avoid overheating. Well, the worst enemy of lithium-ion batteries is high temperature - they absolutely cannot tolerate overheating. Therefore, do not expose your mobile devices to direct sunlight or place them near heat sources such as electric heaters. Maximum permissible temperatures at which lithium-ion batteries can be used: from –40°C to +50°C

Also, you can look

Lithium-ion (Li-ion) batteries used in most modern tablets, smartphones and laptops require different maintenance and operation compared to nickel-cadmium (Ni-Cd) and nickel-metal hydride (Ni-MH) batteries used in earlier devices.

In fact, proper care of your lithium-ion battery can increase its lifespan by 15 times compared to misuse. This article will provide tips on how to maximize the life cycle of expensive lithium-ion batteries in all your portable devices.

Just recently, Fred Langa, a journalist for the Internet portal Windows Secrets, had to replace a damaged smartphone - and it was his mistake.

The main symptom did not bode well - the phone case was deformed because the body of the device itself began to bend.

Upon disassembly and detailed examination, it turned out that the smartphone’s battery was swollen.

Initially, Fred did not notice any changes: the battery looked more or less normal when looking at it face-on (Figure 1). However, when the battery was placed on a flat surface, it became obvious that its top and bottom edges were no longer flat and parallel to each other. There was a serious bulge on one side of the battery (Figure 2). This bulge caused the phone to bend and become deformed.

The bulging of the battery indicated a serious problem: the accumulation of toxic gases under high pressure inside the battery.

The battery case did its job perfectly, but the toxic gases made the battery look like a tiny pressure cooker bomb just waiting to detonate.

In Fred's case, both the phone and the battery were damaged - it was time to buy a new smartphone.

The sad thing is that this problem could have been easily prevented. The final part of the article will highlight Fred's mistakes.

To avoid repeating the mistakes of the past with the new smartphone and other lithium-ion devices such as tablets, laptops, Fred began to seriously research the proper operation and maintenance of lithium-ion batteries.

Fred wasn't interested in extending battery life - these techniques are familiar. Most devices offer manual or automatic power-saving modes and methods for adjusting screen brightness, slowing down processor performance, and reducing the number of apps running.

Fred rather focused on battery life extension issues - ways to keep the battery in good working order and extend the battery life to its maximum level.

This article includes a brief thesis statement based on Fred's research. Follow these five tips to ensure your lithium-ion batteries perform well, last, and safely in all your portable devices.

Tip 1: Monitor the temperature and do not overheat the battery

Surprisingly, heat is one of the main enemies of lithium-ion batteries. Causes of battery overheating may include misuse factors, such as the speed and duration of the battery's charging and discharging cycles.

The external physical environment also matters. Simply leaving a device with a lithium-ion battery in the sun or in a closed car can significantly reduce the battery's ability to accept and hold a charge.

The ideal temperature conditions for lithium-ion batteries is a room temperature of 20 degrees Celsius. If the device heats up to 30C, its ability to carry a charge is reduced by 20 percent. If the device is used at 45C, which is easily achievable in the sun or when the device is intensively used by resource-intensive applications, the battery capacity is reduced by about half.

So, if your device or battery becomes noticeably warm during use, try moving to a cooler location. If this is not an option, try to reduce the amount of power your device uses by disabling unnecessary apps, services, and features, lowering the screen brightness, or activating the device's power-saving mode.

If this still doesn't help, turn off the device completely until the temperature returns to normal. For even faster cooling, remove the battery (of course, if the design of the device allows it) - this way the device will cool down faster due to physical separation from the power source.

By the way, although high temperatures are the main problem with lithium-ion batteries, low-temperature operating conditions do not cause serious concern. Cold temperatures do not cause long-term damage to the battery, although a cold battery will not be able to produce all the power it could potentially produce at its optimal temperature. The drop in power becomes very noticeable at temperatures below 4C. Most consumer-grade lithium-ion batteries essentially become useless at temperatures near or below freezing.

If a device with a lithium-ion power supply becomes excessively cold for any reason, do not attempt to use it. Leave it unplugged and move it to a warm place (pocket or heated room) until the device reaches normal temperature. As with overheating, physically remove the battery and separate heating will speed up the warm-up process. After the battery warms up to normal temperature, its electrolytic properties will be restored.

Tip 2: Unplug the charger to save battery

Recharge - i.e. Connecting the battery to a high voltage source for too long can also reduce the battery's ability to hold a charge, shorten its service life, or what is called “kill it outright.”

Most consumer-grade lithium-ion batteries are designed to operate at a voltage level of 3.6V per cell, but operate at a higher 4.2V when charging. If the charger supplies high voltage for too long, the internal battery may be damaged.

In severe cases, overcharging can lead to what engineers call “catastrophic” consequences. Even in moderate cases, the excess heat generated during recharging will create the negative temperature effect described in the first tip.

High-quality chargers can work in concert with the circuitry of modern lithium-ion batteries, reducing the danger of overcharging by reducing the charging current in proportion to the battery's charge.

These properties vary significantly depending on the type of technology used in the battery. For example, when using nickel-cadmium (Ni-Cd) and nickel-metal hydride (Ni-MH) batteries, try to leave them connected to the charger for as long as possible. This is due to the fact that older types of batteries have a high rate of self-discharge, i.e. they begin to lose a significant amount of stored energy immediately after being disconnected from the charger, even if the portable device itself is turned off.

In fact, a nickel-cadmium battery can lose up to 10 percent of its charge in the first 24 hours after charging. After this period of time, the self-discharge curve begins to level off, but the nickel-cadmium battery continues to lose 10-20 percent per month.

The situation with nickel-metal hydride batteries is even worse. Their self-discharge rate is 30 percent higher than that of their nickel-cadmium counterparts.

However, lithium-ion batteries have a very low self-discharge rate. A good working battery will only lose 5 percent of its charge in the first 24 hours after charging and another 2 percent within the first month after that.

Thus, there is no need to leave the device with a lithium-ion battery connected to the charger until the last moment. For best results and extended battery life, unplug the charger when a full charge is indicated.

New lithium-ion battery devices do not need to be charged extensively before first use (8 to 24 hours of charging is recommended for devices with nickel-cadmium and nickel-metal hydride batteries). Lithium-ion batteries are maximally charged when they indicate 100 percent charge. Extended charging is not necessary.

Not all discharge cycles have the same effect on the condition of the battery. Prolonged and intensive use generates more heat, seriously straining the battery, and shorter, more frequent discharge cycles, on the contrary, extend the battery life.

You might think that increasing small discharge/charge cycles can seriously reduce the life of the power supply. This was only natural for outdated technologies, but does not apply to modern lithium-ion batteries.

Battery specifications can be misleading because... Many manufacturers view the charge cycle as the time required to reach a 100 percent charge level. For example, two charges from 50 to 100 percent are equivalent to one full charge cycle. Likewise, three cycles of 33 percent or 5 cycles of 20 percent are also equivalent to one full cycle.

In short, a large number of small charge-discharge cycles does not reduce the total number of full charge cycles for a lithium battery.

Again, the heat and high load from heavy discharges reduce battery life. Therefore, try to reduce the number of deep discharges to a minimum. Do not allow the battery charge level to drop to values ​​close to zero (when the device turns itself off). Instead, consider the bottom 15 to 20 percent of your battery charge as an emergency reserve—for emergencies only. Get used to replacing the battery if possible, or connecting the device to an external power source before the battery is completely drained.

As you know, fast discharging and fast charging are accompanied by the release of excess heat and negatively affect the battery life.

If you have used the device intensively under high loads, allow the batteries to cool to room temperature before connecting to the charger. The battery will not be able to accept a full charge if it is heated.

While charging the device, monitor the temperature of the battery - it should not overheat too much. A hot battery during charging usually indicates that too much current is flowing quickly.

Overcharging is most likely with cheap, unbranded chargers that use fast charging circuits or with wireless (inductive) chargers.

A cheap charger can be a regular transformer with wires connected to it. Such “silent charges” simply distribute the current and practically do not receive feedback from the device being charged. Overheating and overvoltage are very common when using chargers like this, which slowly destroys the battery.

“Fast” charges are designed to provide a minute charge, not a long hour-long charge. There are different approaches to fast charge technology, and not all of them are compatible with lithium-ion batteries. If the charger and battery are not designed to work together, rapid charging can cause overvoltage and overheating. Generally speaking, it is better not to use a charger from one brand to charge a portable device from another brand.

Wireless (inductive) chargers use a special charging surface to restore the battery's charge. At first glance, this is very convenient, but the fact is that such charges emit excess heat even in normal operation (Some kitchen stoves use induction to heat pots and pans).

Lithium batteries not only suffer from heat, but also waste energy when charging wirelessly. By its nature, the efficiency of an inductive charger is always lower than its conventional counterpart. Here everyone is free to make their own choice, but for Fred, increased heating and lower efficiency are sufficient factors to refuse such devices.

In any case, the safest approach is to use the included charger recommended by the manufacturer. This is the only guaranteed way to keep temperature and voltage within normal limits.

If an OEM charger is not available, use a low output charger to reduce the chance of battery damage due to high power being applied quickly.

One low current output power source is the USB port on a regular computer. A standard USB 2.0 port provides 500mA (0.5A) current per port, while USB 3.0 provides 900mA (0.9A) per port. For comparison, some dedicated chargers can output 3000-4000mA (3-4A). The low current ratings of USB ports generally ensure safe, normal-temperature charging for most modern lithium-ion batteries.

Tip 5: Use a spare battery if possible

If your device allows for quick battery replacement, having a spare battery is a great insurance policy. This not only doubles the operating time of the device, but also eliminates the need to completely discharge the battery or use a fast charge. When the battery charge reaches 15-20 percent, simply replace the dead battery with a spare one, and you will instantly get a full charge of the device without any overheating problems.

A spare battery has other benefits as well. For example, if you find yourself in a situation where the installed battery becomes overheated (for example, due to heavy use of the device or high ambient temperatures), you can replace the hot battery to cool it down faster while continuing to use the device.

Having two batteries eliminates the need for fast charging - you can safely use the device while the battery is slowly charging from a safe power source.

Fred's Fatal Mistakes

Fred suggested that he might have damaged his smartphone battery during a road trip. He used the device's GPS feature to navigate during a clear, sunny day. The smartphone was left in the sun for a long time in a holder near the dashboard of the car; the brightness of the smartphone was turned on to maximum in order to distinguish the map among the bright rays of the sun.

In addition, all the standard background applications - email, instant messenger, etc. were launched. The device used a 4G module to download music tracks and a Bluetoorth wireless module to transmit sound to the car's head unit. The phone was definitely working under stress.

In order for the phone to receive power, it was connected to a 12V adapter, purchased based on the criteria of low price and availability of the correct connector.

The combination of direct sunlight, high processor load, the screen turned on at maximum brightness, and the questionable quality of the adapter led to excessive overheating of the smartphone. Fred remembers with horror how hot the device was when pulled out of the holder. This severe overheating was precisely the catalyst for the death of the battery.

Apparently, the problem got worse at night when Fred left the device plugged in all night using a third-party charger without checking when the battery was fully charged.

With his new smartphone, Fred will only use the included charger and spare battery. Fred hopes for a long and safe life for both the battery and the phone, which he plans to achieve with the help of the tips listed.

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