Lithium-ion and lithium-polymer batteries

Engineering thought is constantly evolving: it is stimulated by constantly emerging problems that require the development of new technologies for their solution. Nickel-cadmium (NiCd) batteries were replaced by nickel-metal hydride (NiMH) batteries, and now they are trying to take the place of lithium-ion (Li-ion) batteries. NiMH batteries have to some extent pushed NiCd out, but due to such indisputable advantages of the latter as the ability to deliver high current, low cost and long service life, they could not provide their full replacement. But what about lithium batteries? What are their features and how do Li-pol batteries differ from Li-ion? Let's try to understand this issue.

As a rule, when buying a mobile phone or laptop, we all do not think about what kind of battery they have inside and how these devices generally differ. And only then, faced in practice with the consumer qualities of certain batteries, we begin to analyze and choose. For those who are in a hurry and want to immediately get an answer to the question of which battery is optimal for a cell phone, I will answer briefly - Li-ion. Further information is intended for the curious.

To begin with, a small excursion into history.

The first experiments to create lithium batteries began in 1912, but only six decades later, in the early 70s, they were first introduced into household devices. Moreover, I emphasize, these were exactly the batteries. Subsequent attempts to develop lithium batteries (rechargeable batteries) have been unsuccessful due to safety concerns. Lithium, the lightest of all metals, has the highest electrochemical potential and provides the highest energy density. Batteries using lithium metal electrodes have both high voltage and excellent capacity. But as a result of numerous studies in the 80s, it was found that the cyclic operation (charge - discharge) of lithium batteries leads to changes on the lithium electrode, as a result of which thermal stability decreases and there is a threat of the thermal state going out of control. When this happens, the temperature of the cell quickly approaches the melting point of lithium - and a violent reaction begins, igniting the gases that are released. For example, a large number of lithium mobile phone batteries shipped to Japan in 1991 were recalled after several incidents of fire.

Due to the instability inherent in lithium, the researchers turned their eyes towards non-metallic lithium batteries based on lithium ions. Having lost a little at the same time in energy density and taking some precautions during charging and discharging, they got safer so-called Li-ion batteries.

The energy density of Li-ion batteries is usually twice the density of standard NiCd, and in the future, thanks to the use of new active materials, it is expected to increase it even more and achieve a threefold superiority over NiCd. In addition to the large capacity, the Li-ion battery during discharge behaves similarly to NiCd (the shape of their discharge characteristics is similar and differs only in voltage).

At the moment, there are many varieties of Li-ion batteries, and you can talk for a long time about the advantages and disadvantages of one type or another, but it is impossible to distinguish them by their appearance. Therefore, we note only those advantages and disadvantages that are inherent in all types of these devices, and consider the reasons that caused the birth of lithium-polymer batteries.

Main advantages.

• High energy density and, as a result, high capacity with the same dimensions compared to nickel-based batteries.
• Low self-discharge.
• High single cell voltage (3.6 V versus 1.2 V for NiCd and NiMH), which simplifies the design - often the battery consists of only one cell. Many manufacturers today use such a single-cell battery in cell phones (remember Nokia). However, to provide the same power, a higher current must be delivered. And this requires ensuring a low internal resistance of the element.
• Low maintenance (running costs) - the result of no memory effect requiring periodic discharge cycles to restore capacity.

Disadvantages.

Li-ion battery technology is constantly improving. It is updated approximately every six months, and it is difficult to understand how new batteries behave after long-term storage.

In a word, everyone would have a good Li-ion battery if it were not for the problems with ensuring the safety of its operation and its high cost. Attempts to solve these problems led to the emergence of lithium-polymer (Li-pol or Li-polymer) batteries.

Their main difference from Li-ion is reflected in the name and lies in the type of electrolyte used. Initially, in the 70s, a dry solid polymer electrolyte was used, similar to a plastic film and not conducting electric current, but allowing the exchange of ions (electrically charged atoms or groups of atoms). The polymer electrolyte actually replaces the traditional porous electrolyte-impregnated separator.

This design simplifies the manufacturing process, is safer, and allows the production of thin, freeform batteries. In addition, the absence of a liquid or gel electrolyte eliminates the possibility of ignition. The thickness of the element is about one millimeter, so that equipment designers are free to choose the shape, shape and size, up to embedding it into the pieces of clothing.

But so far, unfortunately, dry Li-polymer batteries have insufficient electrical conductivity at room temperature. Their internal resistance is too high and cannot provide the amount of current required for modern communications and power supply of laptop hard drives. At the same time, when heated to 60 ° C or more, the electrical conductivity of the Li-polymer increases to an acceptable level, but this is not suitable for mass use.

Researchers continue to develop dry solid electrolyte Li-polymer batteries that operate at room temperature. Such batteries are expected to be commercially available by 2005. They will be stable, allow 1000 full charge-discharge cycles and have a higher energy density than today's Li-ion batteries.

Meanwhile, some types of Li-polymer batteries are currently used as backup power supplies in hot climates. For example, some manufacturers specifically install heating elements that maintain a temperature favorable for the battery.

You ask: how is that? Li-polymer batteries are being sold on the market with might and main, manufacturers equip phones and computers with them, and here we say that they are not yet ready for commercial use. Everything is very simple. In this case, we are talking about batteries not with a dry solid electrolyte. In order to increase the electrical conductivity of small Li-polymer batteries, a certain amount of gelled electrolyte is added to them. And most of the Li-polymer batteries used for mobile phones today are actually hybrids because they contain a gel-like electrolyte. It would be more correct to call them lithium-ion polymer. But most manufacturers simply label them as Li-polymer for promotional purposes. Let us dwell on this type of lithium polymer batteries in more detail, since at the moment they are of the greatest interest.

So what is the difference between a Li-ion and a Li-polymer battery with a gel electrolyte additive? Although the characteristics and efficiency of both systems are similar in many ways, the uniqueness of the Li-ion polymer (you can even call it that) battery is that it still uses a solid electrolyte, replacing a porous separator. Gel electrolyte is added only to increase ionic conductivity.

Technical difficulties and a delay in ramping up production delayed the introduction of Li-ion polymer batteries. This is due, according to some experts, the desire of investors who have invested large sums of money in the development and mass production of Li-ion batteries, to get their investments back. Therefore, they are in no hurry to switch to new technologies, although during mass production, Li-ion polymer batteries will be cheaper than lithium-ion batteries.

And now about the features of the operation of Li-ion and Li-polymer batteries.

Their main characteristics are very similar. The charge of Li-ion batteries is described in sufficient detail in the article. In addition, I will give only a graph (Fig. 1) from, illustrating the stages of charging, and small explanations to it.

The charging time of all Li-ion batteries with an initial charging current of 1C (numerically equal to the nominal value of the battery capacity) is on average 3 hours. Full charge is achieved when the battery voltage is equal to the upper threshold, and when the charge current decreases to a level approximately equal to 3% of the initial value. The battery remains cold during charging. As you can see from the graph, the charging process consists of two stages. At the first (a little over an hour), the voltage rises at an almost constant initial charge current of 1C until the first reaching the upper voltage threshold. At this point, the battery is charged to about 70% of its capacity. At the beginning of the second stage, the voltage remains almost constant, and the current decreases until it reaches the above 3%. After that, the charge is completely terminated.

If it is required to keep the battery in a charged state all the time, it is recommended to recharge after 500 hours, or 20 days. Usually it is carried out when the voltage at the terminals of the battery decreases to 4.05 V and stops when it reaches 4.2 V

A few words about the temperature range when charging. Most types of Li-ion batteries can be charged with a current of 1C at a temperature of 5 to 45 ° C. At temperatures from 0 to 5 ° C, it is recommended to charge with a current of 0.1 C. Charging at sub-zero temperatures is prohibited. The optimum temperature for charging is 15 to 25 ° C.

The charging processes in Li-polymer batteries are almost identical to those described above, so the consumer does not need to know which of the two types of batteries he has in his hands. And all those chargers that he used for Li-ion batteries are suitable for Li-polymer.

And now about the discharge conditions. Typically, Li-ion batteries are discharged to 3.0 V per cell, although for some varieties the lower threshold is 2.5 V. Battery-powered equipment manufacturers generally design devices with a 3.0 V shutdown threshold (for all occasions). What does this mean? The voltage on the battery when the phone is turned on gradually decreases, and as soon as it reaches 3.0 V, the device will warn you and turn off. However, this does not mean at all that he has stopped consuming energy from the battery. Energy, albeit insignificant, is required to determine when the phone's power key is pressed and some other functions. In addition, energy is consumed by its own internal control and protection circuit, and self-discharge, albeit small, is still typical even for lithium-based batteries. As a result, if you leave lithium batteries for a long time without recharging, the voltage on them will drop below 2.5 V, which is very bad. In this case, it is possible to disable the internal control and protection circuit, and not all chargers will be able to charge such batteries. In addition, deep discharge negatively affects the internal structure of the battery itself. A fully discharged battery should be charged at the first stage with a current of only 0.1C. In short, batteries are more likely to be in a charged state than in a discharged state.

A few words about the temperature conditions during discharge (read during operation).

Generally, Li-ion batteries perform best at room temperature. Operating in warmer conditions will seriously shorten their lifespan. Although, for example, a lead-acid battery has the highest capacity at temperatures over 30 ° C, prolonged use in such an environment will shorten the life of the battery. Likewise, Li-ion performs better at high temperatures, which initially counteracts the increase in internal resistance of the battery that results from aging. But the increased energy output is short, as the temperature rise, in turn, promotes accelerated aging, accompanied by a further increase in internal resistance.

The only exceptions are currently lithium polymer batteries with dry solid polymer electrolyte. For them, a temperature of 60 ° C to 100 ° C is vital. And such batteries have occupied their niche in the market of backup sources in places with hot climates. They are placed in a heat-insulated case with built-in heating elements powered from an external network. Li-ion polymer batteries as backup are considered to outperform VRLA batteries in capacity and durability, especially in the field where temperature control is not possible. But their high price remains a deterrent.

At low temperatures, the efficiency of batteries in all electrochemical systems drops sharply. While for NiMH, SLA and Li-ion batteries, -20 ° C is the limit at which they stop functioning, NiCd continues to operate down to -40 ° C. I will only note that we are again talking only about batteries of widespread use.

It is important not to forget that although the battery can operate at low temperatures, this does not mean that it can also be charged under these conditions. The charge susceptibility of most batteries at very low temperatures is extremely limited and the charge current in these cases should be reduced to 0.1C.

In conclusion, I would like to note that you can ask questions and discuss problems related to Li-ion, Li-polymer, as well as other types of batteries on the forum in the accessories sub-forum.

When writing the article, materials were used [- Batteries for mobile devices and laptop computers. Battery analyzers.

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

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

Discharge every 3 months. A full charge for a long time is just as harmful to lithium-ion batteries as being constantly discharged to zero.
Due to the extremely unstable charging process (we often charge the phone as necessary, and where it works, from USB, from an outlet, 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 to reset the so-called high and low battery charge flags. You can read more about this.

Store partially charged... The best condition for long-term storage of a lithium-ion battery is between 30 and 50 percent charge at 15 ° C. If the battery is left fully charged, its capacity will decrease significantly over time. But the battery, which has been gathering dust on the shelf for a long time discharged to zero, most likely is no longer a tenant - 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 into mobile devices, and an external power adapter only lowers the voltage and rectifies the current of the household power supply, 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 the use of an external charger of questionable quality instead of the original one can negatively affect the performance of the battery.

Do not overheat. Well, the worst enemy of lithium-ion batteries is high temperature - they cannot stand overheating at all. Therefore, do not expose mobile devices to direct sunlight or leave them in the immediate vicinity of 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 see

Which is widespread in modern household electronic equipment and finds its application as an energy source in electric vehicles and energy storage systems in energy systems. It is the most popular type of battery in devices such as cell phones, laptops, electric vehicles, digital cameras and camcorders. The first lithium-ion battery was released by Sony Corporation in 1991.

Specifications

Lithium-ion batteries exhibit the following characteristics, depending on the electro-chemical scheme:

• The voltage of a single cell is 3.6 V.
• Maximum voltage 4.2 V, minimum 2.5-3.0 V. Chargers maintain a voltage in the range of 4.05-4.2 V
• Energy density: 110 ... 230 W * h / kg
• Internal resistance: 5 ... 15 mOhm / 1Ah
• Number of charge / discharge cycles until loss of 20% capacity: 1000-5000
• Fast charge time: 15 min - 1 hour
• Self-discharge at room temperature: 3% per month
• Load current relative to capacity (C):
  • constant - up to 65C, pulsed - up to 500C
  • most acceptable: up to 1C
• Operating temperature range: −0 ... +60 ° C (battery charging is not possible at negative temperatures)

Device

A lithium-ion battery consists of electrodes (cathode material on aluminum foil and anode material on copper foil) separated by porous separators impregnated with electrolyte. The package of electrodes is placed in a sealed case, the cathodes and anodes are connected to the current collector terminals. The body has a safety valve that relieves internal pressure in case of emergency and violation of operating conditions. Lithium ion batteries differ in the type of cathode material used. The carrier of current in a lithium-ion battery is a positively charged lithium ion, which has the ability to be incorporated (intercalated) into the crystal lattice of other materials (for example, graphite, oxides and metal salts) with the formation of a chemical bond, for example: into graphite with the formation of LiC6, oxides (LiMO 2) and metal salts (LiM RON). Initially, metal lithium was used as negative plates, then coal coke. In the future, graphite began to be used. Until recently, lithium oxides with cobalt or manganese were used as positive plates, but they are increasingly being replaced by lithium ferro-phosphate, which turned out to be safe, cheap and non-toxic and can be recycled in an environmentally friendly manner. Lithium-ion batteries are used in combination with a control and management system - BMS or BMS (battery management system) and a special charge / discharge device. Currently, three classes of cathode materials are used in the mass production of lithium-ion batteries: - lithium cobaltate LiCoO 2 and solid solutions based on isostructural lithium nickelate - lithium manganese spinel LiMn 2 O 4 - lithium ferrophosphate LiFePO 4. Electro-chemical schemes of lithium-ion batteries: lithium-cobalt LiCoO2 + 6xC → Li1-xCoO2 + xLi + C6 lithium-ferro-phosphate LiFePO4 + 6xC → Li1-xFePO4 + xLi + C6

Due to their low self-discharge and a large number of charge-discharge cycles, Li-ion batteries are most preferable for use in alternative energy. Moreover, in addition to the BMS system (IMS), they are equipped with inverters (voltage converters).

Advantages

• High energy density.
• Low self-discharge.
• Lack of memory effect.
• Maintenance free.

disadvantages

The first generation Li-ion batteries were subject to explosive effects. This was due to the fact that they used a metal lithium anode, on which, in the process of multiple charging / discharging cycles, spatial formations (dendrites) appeared, leading to the closure of the electrodes and, as a result, fire or explosion. This problem was finally solved by replacing the anode material with graphite. Similar processes took place on the cathodes of lithium-ion batteries based on cobalt oxide when the operating conditions were violated (overcharging). Lithium-ferro-phosphate batteries are completely devoid of these disadvantages. In addition, all modern lithium-ion batteries have built-in electronic circuitry to prevent overcharging and overheating due to overcharging.

Li-ion batteries with uncontrolled discharge can have a shorter life cycle than other types of batteries. When fully discharged, lithium-ion batteries lose the ability to charge when the charging voltage is connected. This problem can be solved by applying a higher voltage pulse, but this negatively affects the further performance of lithium-ion batteries. The maximum "life" of a Li-ion battery is achieved when the charge is limited from above at 95% and the discharge is 15–20%. This operating mode is supported by the BMS monitoring and control system (BMS), which is included with any lithium-ion battery.

Optimal storage conditions for Li-ion batteries are achieved at a charge level of 40–70% of the battery capacity and a temperature of about 5 ° C. In this case, low temperature is more important for low capacity losses during long-term storage. The average shelf life (service life) of a lithium-ion battery is 36 months on average, although it can range from 24 to 60 months.

Loss of storage capacity:

According to all current regulations for the storage and operation of lithium-ion batteries, to ensure long-term storage, it is necessary to recharge them up to 70% of their capacity once every 6-9 months.

see also

Notes (edit)

Literature

• Khrustalev D.A. Accumulators. M: Emerald, 2003.
• Yuri Filippovsky Mobile food. Part 2. (RU). ComputerraLab (May 26, 2009). - Detailed article on Li-ion batteries .. Retrieved May 26, 2009.

Links

• GOST 15596-82 Terms and definitions.
• GOST 61960-2007 Lithium accumulators and storage batteries
• Lithium-ion and lithium-polymer batteries. iXBT (2001)
• Domestic lithium-ion batteries

Most modern electronic devices, such as a laptop, telephone or player, are equipped with lithium-ion batteries, which act as self-contained power sources. These ionic batteries were developed relatively recently, but due to their characteristics, they have gained great popularity among designers and manufacturers of gadgets. Now, in addition to various household appliances, many tools for decoration and repair, screwdrivers or cutting machines are equipped with such power sources. This article discusses the types of lithium-ion batteries, their areas of application and the principle of operation.

Types of lithium ion batteries

Rechargeable batteries, operating on the principle of storing energy and delivering it to the consumed device, are of several types, which can be combined into one lithium-ion unit. These batteries include:

1. Lithium cobalt battery. Such a device consists of a graphite anode and a cathode made of cobalt oxide. The cathode has a plate-like structure with gaps between the parts, therefore, when power is consumed, lithium ions are supplied to the plates from the anode, an electromagnetic reaction occurs, and voltage is supplied to the terminals. The disadvantage of such a system is the weak resistance of the mechanism to temperature extremes, since with negative indicators, the battery is discharged, even if it is not connected to the consumer. During recharging of the product, the direction of the current changes, and lithium ions enter the anodes through the cathodes, their accumulation occurs, and the voltage rises. It is strictly forbidden to connect the charger to a battery, the nominal voltage of which is higher than the indicator of the part, otherwise the battery may overheat, the plates will melt, and the case will crack;
2. Lithium manganese battery. Also applies to lithium-ion batteries, the working environment of which is made of manganese spinel in the form of three-dimensional cruciform tunnels. Unlike the cobalt system, this type of base ensures the unimpeded passage of lithium ions from the anode to the cathode and further to the device contacts. The main advantage of a lithium-ion manganese battery is its low material resistance, which is why such batteries are often used for hybrid vehicles, tools that consume a large amount of current, or in medical equipment that operates autonomously. It is allowed to heat the battery during recharging up to 80 degrees, and the rated current can be up to 20-30 Amperes. It is not recommended to act on the battery with a current, the voltage of which is higher than 50A, for more than two seconds, otherwise the spinels may overheat and fail;

1. Lithium ion rechargeable batteries with iron phosphate cathode. Such a battery is rare due to the relatively high production cost, and its final price is slightly higher than that of other lithium-ion batteries. The phosphate cathode has a great advantage: it is the service life of the product and the frequency of recharging is significantly superior to similar devices. Most often, these batteries are guaranteed from 10 to 50 years or about 500 charging cycles. Due to these characteristics, iron phosphate batteries are often used in industry when it is necessary to obtain a high output voltage;
2. Lithium Nickel Manganese Cobalt Oxide Ionic Batteries. This is the most practical, in terms of production cost and finished product reliability, a combination of materials for making a cathode. Due to the electrochemical properties of the listed substances, the cathode made of them has low resistance values, therefore, during a long idle time of the battery, the discharge will be minimal. Also, by increasing the size of the glass or cathode cell, you can increase the total battery capacity or increase the voltage. The secret lies in the combination of manganese and nickel, which, when properly combined, creates a chain with high levels of electrochemical properties;
3. Lithium titanate battery. Developed in the early 1980s, unlike ion batteries with a graphite core, the cathode of this device is made from lithium titanate nanocrystals. The cathode made of this material allows the battery to be recharged in a short period of time and to maintain the voltage with zero resistance. This unit is often used in autonomous street lighting systems, when it is necessary to accumulate energy in a short time and give it to the consumer for a long time. The disadvantage of such a system is the relatively high cost of the finished battery, but it quickly pays off due to the increased service life of the part.

Important! All the listed lithium-ion batteries are non-serviceable batteries, therefore, in the event of damage or failure, it will not be possible to repair or perform service work to add electrolyte. Any manipulations to open the battery cover will lead to the destruction of the battery plates and complete failure.

How lithium-ion batteries work

All lithium-ion batteries have a similar structure, which has a few minor differences that do not affect how the part works. The outer shell is made of composite material, plastic or thin non-ferrous metal, which is very rare. Most often, the battery consists of a plastic case, metal terminals for contact with the consumer, and internal rods with positive and negative voltages. The internal lithium is charged by connecting an external device with a stable current, but each product has a primary charge, which occurs due to a chemical reaction between the anode and cathode.

The processes on the negative electrode made of carbonaceous material, which looks like natural layered graphite, are disordered, electrically charged atoms move through the matrix without losing voltage. All indicators in this sector are negative.

The positive electrode of a lithium battery is made exclusively from cobalt or nickel oxides and lithium manganese spinels. During the discharge, lithium ions move away from the carbon core and, having reacted with oxygen, penetrate the cathode and rush outward, but they cannot leave the battery body. The charged lithium ions lose their voltage and remain on the anode surface until the lithium is charged. During charging, the whole process takes place in reverse order.

Lithium-ion battery design

As an alkaline battery, a lithium battery is manufactured in the form of a cylinder or may be prismatic. In a cylindrical battery, rolled electrodes are used as a core, insulated with a special sheath and placed in a metal case, which is connected to negatively charged cells. To maintain polarity, the minus contact is located at the bottom, and the plus contact is at the top of the part, and these elements should not touch each other, otherwise the current will circulate through the conductor, which will lead to spontaneous discharge.

The prismatic shape of a lithium-ion battery is quite common. In this design, the core is formed by folding special plates on top of each other, which are at a minimum distance between themselves. Such a system allows for higher technical characteristics, but due to the tight fit of the plates while the batteries are being charged, overheating of the core and melting of the mesh are possible, which leads to a decrease in the productivity of the part.

It is not uncommon to find a combined lithium-ion battery device system where coiled electrodes are formed into an oval cylinder. In this case, the rules of smoothness of the transition are observed, and at the same time, the straight section imitates the plate-like shape. Such batteries have the characteristics of both types of products, their service life is much longer.

During the chemical reaction and operation of the battery, gases are formed inside the case, which contain harmful substances. For the prompt removal of these vapors in the case of lithium-ion batteries, there is an outlet that has a connection with the banks and in time removes the accumulated gas from the battery cavity. Some high power batteries are equipped with a special valve that is released during critical vapor build-up.

Lithium-ion battery test

The lithium charges inside the battery need to be checked periodically, despite the fact that the indicated battery is considered unserviceable, since its case is sealed, the battery must still be checked using a special device.

Inspection always begins with an external inspection, during which the body of the part is checked for cracks and deformations. Also, the terminals of the battery are inspected, they are cleaned from oxidation and other contaminants.

Important! It is necessary to keep the battery clean, not allowing the contacts to close together, as this can lead to a complete discharge of the battery, it will be very problematic to restore it.

To check the internal condition of the core, a load plug is used, which is connected to the terminals and measures the nominal voltage in the network. Then a discharge is applied to the battery, and the device reads the indicators for holding the current inside the part. It is important to take into account that at the time of the test, the battery must be fully charged, otherwise the readings will be inaccurate.

Lithium ion battery applications

Lithium ion batteries are used in many applications, depending on their configuration, shape and voltage rating. The most common use of batteries is in the automotive industry, each vehicle has its own power source, which is responsible for starting the car and performs other functions.

Also, these batteries are used in mobile devices, laptops and other gadgets. The device of such batteries is similar to automobile ones, the only difference is in the dimensions of the products, which can be the size of a matchbox.

Recently, it has become popular to introduce lithium-ion batteries into uninterruptible power systems at home and as emergency sources of electricity, while the battery is permanently connected to the central grid. During the operation of the devices from a simple power plant, the battery is charged, and when the power is turned off, it automatically begins to supply current to the consumer. In this case, the rechargeable battery must be correctly positioned and provided with overheating protection systems.

Video

The operating time of modern smartphones without recharging is determined by their battery and its characteristics.

What kind of batteries are there?

Nickel-cadmium (Ni-Cd) and nickel-metal hydride (Ni-MH) batteries are no longer relevant - they worked well for a long time, but had a number of drawbacks. In our gadgets, in most cases, lithium-based batteries are used - lithium-ion (Li-Ion) and lithium-polymer (Li-Pol).

One of the main characteristics of a battery is its capacity. It determines how much electricity the battery can store, and how long the device can work autonomously. The most common batteries are those with a capacity of 2,000 to 3,000 mAh (milliamperes / hour). The dimensions of lithium-ion sources remain very compact, unlike their predecessors.

Lithium-polymer batteries differ from lithium-ion batteries in a variety of geometric shapes and, which is especially important now, in their minimum thickness, which starts from 1 mm. This allows them to be used in very thin smartphones.

Lithium batteries have a long service life when used correctly. The manufacturers of many well-known smartphones provided for the replacement of the battery only in the service center, making the device body monolithic, and the back cover and battery non-removable. Without special equipment and knowledge, the user will not be able to carry out this operation on his own.

Temperature during operation. The capacity of the battery is directly affected. High temperature promotes faster energy storage, at low temperature the capacity drops significantly. If you use an insufficiently charged one, it will quickly discharge. Moreover, there is a risk of lowering the charge to zero, which is extremely undesirable - lithium batteries suffer from a full discharge.

And the opposite situation. A 100% charged smartphone is used in direct sunlight. Figuratively speaking, in this case, 100% of the charge turns into 110%, and a surplus of accumulated electricity is obtained, which can lead to a decrease in capacity.

Based on this, it is worth observing the temperature conditions of the gadget. And we are not talking about natural heating during active use - such an increase in temperature for the battery does not pose a danger

Charging time and charger. Each lithium source is equipped with a special controller that must protect it from excess current. When a full charge is reached, the incoming current is cut off.

Errors and inaccuracies are possible in the operation of the controller, which lead to overcharging. Sometimes this is due to the use of non-original smartphone chargers. It is not recommended to leave a charging smartphone in the outlet for a long time after it reaches a full charge. You also need to use original chargers or those whose parameters.

Lithium batteries need to be charged without waiting for the device to turn off completely, for example, by 10-15% of the residual charge. They can be powered whenever possible during the day, for example, from the USB port of a work computer or in a car. It is not necessary to achieve a full charge.

Storage. If the owner of the smartphone plans not to use the device for a long time, the recommended battery charge level in this case should be about 50%.

Lithium batteries are charged approximately 1200 times. Simple arithmetic suggests that the battery life will last for at least 3 years. By following the above guidelines, you can extend the battery life.