Lithium polymer batteries. Types and device. Advantages and disadvantages. Li-Ion or Li-Po: What is the difference and what to choose

Without proper battery life, the whole point of a mobile device is lost. The user finds himself tied to the power grid and cannot be in touch while moving. In the company "Magazin-Details.RU" you can buy a lithium-polymer battery and solve problems with the rapid discharge of the device.

How to order a lithium-polymer battery at Magazin-Details.RU

Do you want to quickly buy Li-Pol batteries and not wait for spare parts to be delivered? Contact our store. We are suppliers to leading service centers and spare parts stores, and we are also preferred by retail customers from all over the country.

Our company has been selling and collaborating directly with equipment manufacturers for several years. We specialize in supplying high quality original spare parts. This guarantees the customer uninterrupted battery life.

Also here you will find Li-Ion batteries for laptops, smartphones, phones and tablets.

Our company strives to simplify the ordering procedure as much as possible. To buy a polymer lithium-ion battery, the client does not need to waste time and come to our office. All issues will be quickly resolved via the website, email or phone.

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Battery production technologies do not stand still and gradually Ni-Cd (nickel-cadmium) and Ni-MH (nickel-metal hydride) batteries are being replaced on the market by batteries based on lithium technology. Lithium polymer (Li-Po) and lithium-ion (Li-ion) batteries are increasingly used as a power source in various electronic devices

Lithium- silver-white, soft and ductile metal, harder than sodium, but softer than lead. Lithium is the lightest metal in the world! Its density is 0.543 g/cm3. It can be processed by pressing and rolling. Lithium deposits are found in Russia, Argentina, Mexico, Afghanistan, Chile, USA, Canada, Brazil, Spain, Sweden, China, Australia, Zimbabwe and Congo

Excursion into history

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

Because of lithium's inherent instability, researchers have turned their attention to non-metallic lithium batteries based on lithium ions. By playing around a little with energy density and taking some precautions when charging and discharging, they came up with safer so-called lithium-ion (Li-ion) batteries.

The energy density of Li-ion batteries is usually several times higher than that of standard NiCd and NiMH batteries. Thanks to the use of new active materials, this superiority is increasing every year. In addition to its large capacity, Li-ion batteries behave similarly to nickel batteries when discharged (their discharge characteristics are similar and differ only in voltage).

Today 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 appearance. Therefore, we will note only those advantages and disadvantages that are characteristic of all types of these devices, and consider the reasons that led to the birth of lithium-polymer (Li-Po) batteries.

The Li-ion battery was good for everyone, but problems with ensuring the safety of its operation and high cost led scientists to create a lithium-polymer battery (Li-pol or Li-po).

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 plastic film and not conducting electricity, but allowing the exchange of ions (electrically charged atoms or groups of atoms). The polymer electrolyte essentially replaces the traditional porous separator impregnated with electrolyte, so they have a flexible plastic shell, are lighter, have higher current output and can be used as power batteries for devices with powerful electric motors.

This design simplifies the production process, is characterized by higher safety and allows the production of thin batteries of any shape. The minimum thickness of the element is about one millimeter, so equipment developers are free to choose the shape, shape and size, even including its implementation in clothing fragments.

Main advantages

Lithium-ion and lithium-polymer batteries with the same weight are superior in energy intensity to nickel (NiCd and Ni-MH) batteries
Low self-discharge
High voltage per cell (3.6-3.7V versus 1.2V-1.4 for NiCd and NiMH), which simplifies the design - often the battery consists of only one cell. Many manufacturers use just such a single-cell battery in various compact electronic devices (cell phones, communicators, navigators, etc.)
Element thickness from 1 mm
Possibility of obtaining very flexible forms

Flaws

The battery is subject to aging, even if it is not used and just sitting on a shelf. For obvious reasons, manufacturers are silent about this problem. The clock starts ticking from the moment the batteries are produced at the factory, and the decrease in capacity is the result of an increase in internal resistance, which in turn is generated by oxidation of the electrolyte. Eventually, the internal resistance will reach a level where the battery can no longer supply the stored energy, even though there is enough energy in the battery. After two or three years, it often becomes unusable.
Higher cost compared to NiCd and Ni-MH batteries
When using lithium polymer batteries, there is always a risk of ignition, which can occur due to shorted contacts, improper charging, or mechanical damage to the battery. Since the combustion temperature of lithium is very high (several thousand degrees), it can ignite nearby objects and cause a fire.

Main characteristics of Li-Po batteries

As mentioned above, lithium-polymer batteries with the same weight are several times higher in energy intensity than NiCd and Ni-MH batteries. The service life of modern Li-Po batteries, as a rule, does not exceed 400-500 charge-discharge cycles. For comparison, the service life of modern Ni-MH batteries with low self-discharge is 1000-1500 cycles.

Technologies for the production of lithium batteries do not stand still and the above figures may lose relevance at any time, because Battery manufacturers are increasing their characteristics every month through the introduction of new technological processes for their production.

Of the variety of lithium-polymer batteries available for sale, two main groups can be distinguished: fast-discharge(Hi Discharge) and ordinary. They differ from each other in the maximum discharge current - it is indicated either in amperes or in units of battery capacity, designated by the letter “C”.

Application areas of Li-Po batteries

The use of Li-Po batteries allows you to solve two important problems - increase the operating time of devices and reduce battery weight

Regular Li-Po batteries are used as power sources in electronic devices with relatively low current consumption (mobile phones, communicators, laptops, etc.).

Fast-discharge Lithium polymer batteries are often called " by force"- such batteries are used to power devices with high current consumption. A striking example of the use of “power” Li-Po batteries are radio-controlled models with electric motors and modern hybrid cars. It is in this market segment that the main competition between various manufacturers of Li-Po batteries takes place.

The only area where lithium-polymer batteries are still inferior to nickel ones is the area of super-high (40-50C) discharge currents. In terms of price per capacity, lithium polymer batteries cost about the same as NiMH. But competitors have already appeared in this market segment - (Li-Fe), the production technology of which is developing every day.

Charging Li-Po batteries

Most Li-Po batteries are charged using a fairly simple algorithm - from a constant voltage source of 4.20V/cell with a current limit of 1C (some models of modern power Li-Po batteries allow them to be charged with a current of 5C). The charge is considered complete when the current drops to 0.1-0.2C. Before switching to voltage stabilization mode at a current of 1C, the battery gains approximately 70-80% of its capacity. It takes about 1-2 hours to fully charge. The charger is subject to fairly stringent requirements for the accuracy of maintaining voltage at the end of the charge - no worse than 0.01 V/cell.
Of the chargers on the market, two main types can be distinguished - simple, non-“computer” chargers in the price category of $10-40, designed only for lithium batteries, and universal chargers in the price category of $80-400, designed to serve various types batteries.

The first ones, as a rule, have only an LED charge indication; the number of cans and the current in them are set using jumpers or by connecting the battery to various connectors on the charger. The advantage of such chargers is their low price. The main drawback is that some of these devices cannot correctly detect the end of the charge. They determine only the moment of transition from the current stabilization mode to the voltage stabilization mode, which is approximately 70-80% of the capacity.

The second group of chargers has much wider capabilities; as a rule, they all show the voltage, current, and capacity in mAh that the battery “accepted” during the charging process, which allows you to more accurately determine how charged the battery is. When using a charger, the most important thing is to correctly set the required number of cans in the battery and the charge current on the charger, which is usually 1C.

Li-Po Battery Operation and Precautions

It’s safe to say that lithium polymer batteries are the most “delicate” that exist, i.e. require mandatory compliance with several simple rules. We list them in descending order of danger:

Battery recharge - charge to a voltage exceeding 4.20V per cell
Battery short circuit
Discharge with currents exceeding the load capacity or leading to heating of the Li-Po battery above 60°C
Discharge below 3V voltage per jar
Battery heating above 60ºС
Battery depressurization
Storing in a discharged state

Failure to comply with the first three points leads to a fire, all others - to complete or partial loss of capacity

From all that has been said, the following conclusions can be drawn:

To avoid a fire, you must have a normal charger and correctly set the number of cans to be charged on it.
It is also necessary to use connectors that exclude the possibility of short-circuiting the battery and control the current consumed by the device in which the Li-Po battery is installed
You need to be sure that your electronic device in which the battery is installed does not overheat. At +70ºС, a “chain reaction” begins in the battery, turning the energy stored in it into heat, the battery literally spreads, setting fire to everything that can burn
If you short-circuit an almost discharged battery, there will be no fire; it will quietly and peacefully “die” due to overdischarge
Monitor the voltage at the end of the battery discharge and be sure to turn it off after use
Depressurization is also the reason for failure of lithium batteries. No air should get inside the element. This can happen if the outer protective package (the battery is sealed in a package like heat-shrink tubing) is damaged due to an impact, or damage with a sharp object, or if the battery terminal is severely overheated during soldering. Conclusion - do not drop from a great height and solder carefully
Based on the manufacturers' recommendations, batteries should be stored in a 50-70% charged state, preferably in a cool place, at a temperature not exceeding 30°C. Storing in a discharged state has a negative impact on service life. Like all batteries, lithium polymer batteries have a slight self-discharge.

Li-Po battery assembly

To obtain batteries with high current output or high capacity, parallel connection of batteries is used. If you buy a ready-made battery, then by the marking you can find out how many cans it contains and how they are connected. The letter P (parallel) after the number indicates the number of cans connected in parallel, and S (serial) - in series. For example, "Kokam 1500 3S2P" means a battery connected in series with three pairs of batteries, and each pair is formed by two batteries connected in parallel with a capacity of 1500 mAh, i.e. The battery capacity will be 3000 mAh (when connected in parallel, the capacity increases), and the voltage will be 3.7V x 3 = 11.1V.

If you buy batteries separately, then before connecting them into a battery you need to equalize their potentials, especially for the parallel connection option, since in this case one bank will begin to charge the other and the charging current may exceed 1C. It is advisable to discharge all purchased banks to 3V with a current of about 0.1-0.2C before connecting. The voltage must be monitored with a digital voltmeter with an accuracy of at least 0.5%. This will ensure reliable battery performance in the future.

It is also advisable to perform potential equalization (balancing) even on already assembled branded batteries before their first charge, since many companies that assemble cells into a battery do not balance them before assembly.

Due to the decrease in capacity as a result of operation, in no case should you add new banks in series with the old ones - the battery will be unbalanced.

Of course, you also cannot combine batteries of different, even similar capacities into a battery - for example, 1800 and 2000 mAh, and also use batteries from different manufacturers in one battery, since different internal resistance will lead to unbalance of the battery.

When soldering, you should be careful; you should not allow the terminals to overheat - this can break the seal and permanently “kill” a battery that has not yet been used. Some Li-Po batteries come with pieces of a textolite printed circuit board already soldered to the terminals for easy wiring. This adds extra weight - about 1 g per element, but it takes much longer to heat the places for soldering wires - fiberglass does not conduct heat well. Wires with connectors should be secured to the battery case, at least with tape, so as not to accidentally tear them off when connecting to the charger multiple times

The nuances of using Li-Po batteries

I will give a few more useful examples that follow from what was said earlier, but are not obvious at first glance...

Over the long life of a battery, its elements, due to the initial small dispersion of capacities, become unbalanced - some banks “age” earlier than others and lose their capacity faster. With a larger number of cans in the battery, the process goes faster. This leads to the following rule: it is necessary to monitor the capacity of each battery element.

If a battery is found in an assembly whose capacity differs from other elements by more than 15-20%, it is recommended to refuse to use the entire assembly, or to solder a battery with fewer elements from the remaining batteries.

Modern chargers have built-in balancers, which allow you to charge all elements in the battery separately under strict control. If the charger is not equipped with a balancer, then it must be purchased separately and it is advisable to charge the batteries using it.

An external balancer is a small board connected to each bank, containing load resistors, a control circuit and an LED indicating that the voltage on a given bank has reached the level of 4.17-4.19V. When the voltage on a separate element exceeds the threshold of 4.17V, the balancer closes part of the current “to itself,” preventing the voltage from exceeding the critical threshold.

It should be added that the balancer does not prevent the overdischarge of some cells in an unbalanced battery; it only serves to protect against damage to the elements during charging and as a means of identifying “bad” elements in the battery.

The above applies to batteries composed of three or more elements; for two-can batteries, balancers, as a rule, are not used

According to numerous reviews, discharging lithium batteries to a voltage of 2.7-2.8V has a more detrimental effect on capacity than, for example, recharging to a voltage of 4.4V. It is especially harmful to store the battery in an over-discharged state.

There is an opinion that lithium-polymer batteries cannot be used at subzero temperatures. Indeed, the technical specifications for the batteries indicate an operating range of 0-50°C (at 0°C 80% of the battery capacity is retained). But nevertheless, it is possible to use Li-Po batteries at subzero temperatures, about -10...-15°C. The point is that you don’t need to freeze the battery before use - put it in your pocket where it’s warm. And during use, the internal heat generation in the battery turns out to be a useful property at the moment, preventing the battery from freezing. Of course, the battery performance will be slightly lower than at normal temperatures.

Conclusion

Considering the pace at which technical progress in the field of electrochemistry is moving, it can be assumed that the future lies with lithium energy storage technologies if fuel cells do not catch up with them. Wait and see…

The article uses materials from articles by Sergei Potupchik and Vladimir Vasiliev

What is the difference between a lithium polymer battery and an ion battery?

The vast majority of residents of developed countries have mobile phones, tablets, and laptops. When you purchase a gadget in a store, most likely, you don’t even think about the type of battery it contains. And this is not surprising. Technologies are developing rapidly, including in the field of batteries. Not so long ago, Ni─Cd batteries were used in mobile electronics, which were later replaced by Ni─MH. Then lithium-ion appeared, which quickly conquered the market for portable gadgets. And now they are being squeezed out by lithium polymer batteries. At some point, the user begins to think about what kind of battery he has. What are its advantages and disadvantages? In this article we will try to understand what is the difference between a lithium polymer battery and a lithium ion battery.

Work on creating batteries using lithium has been going on for quite some time. But the first workable copies for household appliances appeared only in the 70s of the last century. But then these were imperfect models with electrodes made of metal lithium. And the operation of such batteries is problematic in terms of safety. There were many unresolved problems with the process of charging and discharging such batteries.

The fact is that lithium metal is very active and has a high electrochemical potential. Its use in batteries can significantly increase energy density. Batteries with Li metal electrodes, which were the first to be developed, have high voltage and large capacity. However, the constant operation of such a battery in charge and discharge mode leads to the fact that the lithium electrode changes.

This leads to the fact that the stability of operation is disrupted and there is a risk of ignition due to the uncontrolled reaction in the battery. The battery cell heats up quickly and, when the temperature rises to the point where lithium melts, a violent reaction occurs with ignition. This was associated with recalls of the first lithium batteries in consumer electronics in the early 90s.

As a result, scientists began to develop batteries based on Li ions. Due to the fact that we had to abandon the use of lithium metal, the energy density decreased somewhat. But on the other hand, safety problems during battery operation were resolved. These new batteries are called lithium-ion batteries.

The energy density of lithium-ion batteries is 2-3 times (depending on the materials used) higher than that of . When discharged, Li─Ion batteries show characteristics similar to Ni─Cd. The only thing in which they are inferior to them is operation at ultra-high discharge currents (more than 10C). To date, many different modifications of lithium-ion batteries have already been released.

They differ in the material used as the cathode, form factor and some other parameters. They are uniquely characterized by a design that includes electrodes immersed in a liquid electrolyte containing lithium ions. This battery cell is placed in a sealed metal shell (steel, aluminum). To control the charging and discharging processes in lithium-ion batteries, there is a printed circuit board called a controller.

To make the picture of Li─Ion batteries complete, let’s consider their advantages and disadvantages.

Advantages of Li─Ion

Slight self-discharge;
High energy density and capacity compared to alkaline ones;
One battery cell has a voltage of about 3.7 volts. For cadmium and metal hydride, this value is 1.2 volts. This allows the design to be significantly simplified. Phones, for example, use batteries that contain only one cell;
There is no memory effect, which means battery maintenance is simplified.

Disadvantages of Li─Ion

A controller is required. This is a printed circuit board that controls the voltage of the battery cell or cells, if there are several of them. The board also controls the maximum discharge current, and in some cases, the temperature of the can. Without a controller, safe operation of a lithium-ion battery is impossible;
Degradation of the Li─Ion system occurs even during storage. That is, after a year, the battery capacity decreases noticeably, even if it is not used. Batteries of other types (alkaline, lead-acid) also gradually degrade during storage, but in them this is less pronounced;
The price of lithium ion is higher than cadmium or .

The capabilities of lithium-ion technology have not been fully developed. Therefore, new batteries are constantly appearing, where certain problems of this type of battery are solved. For more information about what it is, read the article at the link provided.

Li-Pol battery

Due to problems with ensuring safety when charging and discharging Li─Ion batteries, further development of modifications of these batteries began. As a result, lithium polymer batteries were developed. Their difference from ionic ones is in the electrolyte used. It is worth saying that the first developments in this direction were carried out simultaneously with Li─Ion technology. Back in the last century, a dry electrolyte made from a solid polymer was used for the first time. In appearance it looks like a plastic film. This polymer does not conduct current, but does not interfere with ion exchange, which involves the movement of charged atoms or groups of them. In addition to containing electrolyte, the polymer also acts as a porous separator between the electrodes.

The new design has improved safety and simplified battery production. And even more important is that lithium polymer batteries can be produced in almost any shape and very small thickness (up to 1 millimeter).

This makes it possible to make various devices powered by Li─Pol batteries thin, compact and elegant. Some lithium polymer batteries can even be sewn into clothing.

If you heat a lithium polymer battery to 60 degrees Celsius, the conductivity increases. Obviously, this is not suitable for use on phones or tablets. However, dry polymer batteries have found their niche in the market. They are used as backup power sources in conditions of elevated temperatures. There are options when heating elements are installed to provide the temperature necessary for normal battery operation.

Another important point is worth clarifying here. Surely everyone has seen that batteries labeled Li─Pol have been used in smartphones, tablets and laptops for a long time. These are lithium polymer hybrid batteries, so to speak. They are a cross between Li-Ion and dry polymer batteries. Manufacturers producing lithium polymer batteries use a gel-like substance with lithium ions as an electrolyte.

So, almost all lithium polymer batteries in modern mobile gadgets use a gel-like electrolyte. By design, they are a hybrid of ion and polymer batteries. What is the difference between ionic and polymer batteries with gel electrolyte? Their basic electrochemical parameters are approximately the same. The difference between such hybrid batteries is that they use a solid electrolyte instead of a porous separator. As mentioned above, it also acts as a porous separator. And the electrolyte in a gel state is used to increase the electrical conductivity of ions.

Lithium polymer batteries are becoming more widespread on the market and they are the future. At least in the segment of household appliances and consumer electronics. But so far their implementation is not very active. Some market experts explain this by saying that too much money has been invested in the development of Li-Ion batteries. And investors simply want to “recoup” their invested money. read the link.

Features of lithium polymer batteries and rules of their operation

A lithium polymer battery is a modified version of lithium ion batteries. The main difference is the use of a polymer material that acts as an electrolyte. Conductive inclusions with lithium compounds are added to this polymer. Such batteries have been actively developed in recent years and are used in mobile phones, tablets, laptops, radio-controlled models and other equipment. Although lithium batteries are not capable of delivering high discharge currents, some special types of polymer batteries can deliver currents that significantly exceed their capacity. Since lithium polymer batteries are rapidly spreading on the market, you need to have an understanding of their design, operating rules and safety precautions when handling them. This will be discussed in our material today.

The advantage of replacing a liquid organic electrolyte with a polymer one is to increase the safety of battery operation. This is very important for lithium batteries. It was the safe use for commercial purposes that held back their development from the very beginning. In addition, the polymer electrolyte gives much more freedom when choosing the shape of the battery.

The design of Li─Pol batteries was based on the process of transition of a number of polymers into a semiconductor state when electrolyte ions are introduced into them. In this case, the conductivity increases several times.

Researchers were mainly busy selecting a polymer electrolyte for batteries with metallic lithium and Li─Ion models. In theory, the energy density of polymer batteries can be increased several times compared to lithium-ion ones. Today, several groups of Li─Pol batteries can be distinguished, differing in the composition of the electrolyte:
With gel-like homogeneous electrolyte. It is obtained as a result of the introduction of lithium salts into the polymer structure;
With dry polymer electrolyte. This type is made from polyethylene oxide with different lithium salts;

If we compare polymer and liquid electrolytes, it is worth noting the lower ionic conductivity of the former. It decreases significantly at subzero temperatures. So, one problem was to select a composition for an electrolyte with high conductivity. And the second important task was to expand the operating temperature range of polymer batteries. Models of lithium-polymer batteries used in modern technology are not inferior in their characteristics to Li-Ion.

Since there is no liquid electrolyte in a polymer battery, their operational safety is much higher. In addition, they can be made in almost any shape and configuration.

The containers of some models, which contain the jar itself, are made of metallized polymer. Due to crystallization of the polymer electrolyte, the parameters of these batteries are significantly reduced at low temperatures.

There are developments of polymer batteries with a metal anode. Scientists managed to achieve high current density and a significant expansion of the operating temperature range. These types of batteries can also be used in various portable electronics and home appliances. Many leading companies are already producing such batteries.

Moreover, different manufacturers may have different electrode materials, electrolyte composition, and the assembly technology itself. For this reason, the parameters of these batteries are very different. However, all manufacturers agree that the stability of Li─Pol operation is strongly influenced by the homogeneity of the polymer electrolyte. And it depends on the polymerization temperature and the ratio of components.

Now there are many experiments that have been carried out that prove the higher level of safety of polymer batteries compared to ionic ones. This applies to overcharging, accelerated discharge, vibration, compression, short circuit, puncture of lithium polymer batteries.

So, this type of battery has the best development prospects. Below are the results of tests for the safe operation of Li─Pol batteries.
So, this type of battery has the best development prospects. Below are the results of tests for the safe operation of Li─Pol batteries.	Type of test	Battery with gel polymer electrolyte
Battery with liquid electrolyte	Puncture with a needle	There were no changes
Explosion, smoke, electrolyte leakage, temperature increase up to 250°C	Puncture with a needle	Heating up to 200°C
Explosion, electrolyte leakage	Puncture with a needle	Short circuit current
Electrolyte leakage, temperature increase by 100°C	Recharge (600%)	Bloating

There are examples of lithium polymer batteries that are 1 millimeter thick. Such models allow mobile device designers to create very compact equipment. This opens up new possibilities for reducing the size of electronic devices. To reduce the internal resistance of Li-Pol batteries, a gel electrolyte is added. The batteries used in mobile phones use this type of electrolyte. They combine the features of polymer and ion batteries.

What is the difference between Li─Ion and Li─Pol batteries. They relate to and are close in their electrical characteristics. But polymer models use a solid electrolyte. The gel component is added to the electrolyte to reduce the internal resistance of the battery and stimulate ion exchange processes.

In terms of their energy intensity, lithium polymer batteries have a specific energy intensity that is 4-5 times higher and 3-4 times higher. Both of these types belong to . The comparison is made with them, since lithium batteries have largely replaced alkaline batteries in mobile electronics.

Li-Pol batteries have a resource of 500-600 charge-discharge cycles (at a discharge current of 2C). According to this indicator, they are inferior to cadmium ones (1 thousand cycles) and approximately correspond to metal hydride ones.

Production technology and design are constantly being improved and in the future, perhaps, the characteristics will improve. It is also worth noting that in 1-2 years a polymer battery loses approximately 20% of its capacity. In this parameter they correspond to ion batteries.

It should be noted that among polymer batteries for commercial use there are 2 large categories. These are regular and fast-discharge. The latter are often called Hi discharge. The difference between these groups is the maximum permissible discharge current. It can be indicated in absolute value or as a multiple of the nominal capacity.

KKM2500 denotes a regular model with a capacity of 2500 mAh, and the marking KKM2000HD stands for a fast-discharge battery with a capacity of 2000 mAh. Fast-discharge models are not used in household appliances and consumer electronics. Batteries from cell phones and tablets cannot withstand high discharge currents, and therefore are equipped with protection against such operating modes.

The areas of application of lithium polymer batteries arise from the tasks that were posed during their development. This increases the operating time of the device and reduces its weight. Standard Li─Pol models work in various electronics with low current consumption. These are laptops, smartphones, e-readers, tablets.

Models that provide fast discharge are also called “power”. They are used in devices where high current consumption is required. The most well-known area of application for “power” batteries is radio-controlled models.

This market is the most attractive for manufacturers of polymer batteries. In the field of operation of devices with very high discharge currents (up to 50 C), lithium polymer batteries are inferior to alkaline ones. Perhaps in the future lithium models will overcome this limitation. In terms of price, they are approximately the same as nickel-metal hydride.

Operation of lithium polymer batteries

Safety

Lithium batteries in general, and polymer batteries in particular, require rather delicate handling during operation. What you need to remember when using Li─Pol batteries:
Excessive battery charge is harmful (above 4.2 volts per battery cell);
Short circuits must not be allowed;
It is unacceptable to discharge with currents that lead to heating of the battery by more than 60 degrees Celsius;
The battery cannot be depressurized;
Do not discharge the battery below 3 volts;
Heating above 60 degrees is unacceptable;

Discharged storage is not allowed.

Failure to follow these rules can result in a fire at worst, and significant loss of capacity at best.

It is also worth noting that you need to observe the temperature regime and prevent overheating of the polymer battery. This is the weak point of all lithium batteries. If the battery heats up to 70 degrees, then a spontaneous reaction begins in it, which converts energy into heat. The result is ignition and sometimes explosion. If it is possible to control the battery voltage, then it should be monitored especially closely at the end of the discharge.

Another reason for lithium batteries to fail is depressurization. Under no circumstances should air penetrate inside the polymer battery can. Initially, the case is sealed and should not be subjected to impacts or dropped. If you are soldering leads, then you need to do this extremely carefully.

Before storing a polymer battery, it is recommended to charge it halfway. The battery should be stored in a cool place away from direct sunlight.

Like all batteries, lithium polymer batteries have self-discharge, but it is less than that of lead or alkaline batteries. A polymer battery is a modernized version of lithium power sources.

A special gel with certain characteristics is used as a filler for a lithium polymer battery.

In order to decide whether it is worth using li pol advanced batteries, you need to study certain information and take into account the advantages and disadvantages.

The performance of equipment, a portable device or installation largely depends on how correctly the power source is selected. Thus, a lithium ion or lithium ion polymer battery is used to complete portable chargers. In order to make the right choice, you need to know what the difference is. It is mandatory to take into account the pros and cons of power sources.

Interesting video about lithium polymer batteries.

Lithium-ion batteries

The demonstration of the first ion batteries occurred in the last century. Then the developers presented models in which the electrodes were prepared from lithium metal. They were characterized by a low level of safety and short service life. Therefore, lithium metal was replaced with li ions.

The upgraded lithium-ion battery has the following advantages:
Increased capacity, electrolyte density.
Possibility of operation at higher voltage.
Easy to maintain due to lack of memory effect.

The service life of an ion battery also depends on whether the disadvantages are taken into account:

Constant monitoring of voltage, current and temperature levels is required. This requires a special controller. This is exactly what distinguishes ionic batteries from polymer ones.
Gradual reduction in capacity.
The composition must include a proven protective circuit, a controller with the necessary components. Such work requires certain materials and tools. The procedure for manufacturing a protective circuit takes some time. All this leads to an increase in the cost of li ion po batteries by 1.5–2 times.

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Lithium polymer batteries

The development of a high-quality lithium polymer battery began due to the fact that the safety level of ion power sources was low. As a result, manufacturers received batteries that have special advantages in contrast to li.

Instead of the standard electrolytic composition, a dry polymer electrolyte is used, presented in the form of a film. It does not conduct current and does not interfere with the exchange of charged particles. Unlike an ion power source, a porous separator is not included in the polymer battery device.

Due to the fact that this design is used, the level of safety of li pol household batteries is higher. After all, the likelihood of ignition is reduced to zero.

Polymer electrolyte is easy to process. Therefore, manufacturers can easily create a li ion polymer battery of the required shape and optimal configuration. Therefore, such power supplies are used in phones, laptops, portable equipment, and video cameras.

Unfortunately, lithium ion polymer batteries have low electrical conductivity. Its level increases only when heated. But such an effect is not always acceptable. For example, heating the battery is not allowed if there is no cooling system.

The resistance level of li ion polymer batteries is high, so it is quite difficult to obtain the required current value. Because of this, modern devices cannot be equipped with such power sources.

But the above problems are inherent only in those li ion poly power sources in which the electrolyte is presented in dry form.

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Upgraded lithium polymer batteries

The problem associated with the lack of electrical conductivity was solved by introducing certain components into the electrolyte. Now they produce polymer batteries, the electrolyte in which is presented in the form of a gel. These power sources are called lithium ion polymer batteries. They are equipped with the best mobile phones, chargers and portable devices.

Rechargeable polymer batteries are found everywhere, no matter what kind of technology is presented.

Fundamental differences

What to choose: li ion or li polymer battery? Both designs have similar characteristics and parameters. The difference lies in the presence of solid electrolyte in li ion pol batteries.

The upgraded li-ion polymer battery does not come with a porous separator. It is distinguished by increased capacity, long service life, and increased electrical conductivity.

When deciding which battery is best for a phone, manufacturers take into account design features, as well as the difference between pol and li types. Moreover, most often they use ion li polymer batteries, which have all the advantages.

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Features of using lithium batteries

The use of li ion and li ion pol follows a similar principle. To prevent problems you need:

Maintain a voltage of 4.2–2.7 V throughout the entire period of operation. These indicators correspond to the maximum and minimum charge.
Taking into account voltage restrictions introduced by manufacturers. For careful control, the use of proven schemes is allowed.
The service life of batteries charged to 45–46% pol or li is the longest.
The introduction of controllers into ion polymer batteries helps maintain an acceptable voltage level.

Rules for charging lithium polymer batteries

To increase the operating time of the battery without additional recharging, you need to take into account the charging operating rules.

Full discharge is not allowed. Polymer batteries do not have a memory effect. Therefore, the use of the charger is acceptable even with a small discharge. To extend the life of the li ion po battery, you need to charge it more often. In this case, you need to use a “native” charger.
Constantly using a battery that is fully charged is harmful. Therefore, the power source must be discharged to zero at certain intervals. Caused by charging instability and the use of different circuits and devices. With periodic discharge, the likelihood of the formation of lower and upper thresholds is eliminated.
Unused li ion po power supplies are stored at a temperature of 15–20 degrees. The charge level should be 40%. A fully charged power source should not be stored. After all, this is fraught with loss of capacity and deterioration of performance.
Original chargers are used to charge lithium-ion polymer batteries. Some mobile phones have built-in chargers. An external adapter is supplied separately to help stabilize the voltage. Some equipment is not equipped with such devices. Therefore, the battery is removed for charging.
Polymer batteries must not be overheated. Even an excess of 1–2 degrees has a detrimental effect on the condition of the power source. Low temperatures also have a negative impact. Therefore, you need to use the battery only in an acceptable mode.
It is prohibited to operate power sources in close proximity to heaters. The battery should not be exposed to direct sunlight. After all, all this helps to reduce the period of use.
It is unsafe to use chargers that have not been certified. So how do you charge a battery? The best solution is to use tested and certified chargers recommended by manufacturers.
All connectors used must be the same size. This is the only way to eliminate the possibility of shorting the battery.
The temperature of the power supply must be constantly monitored. This is especially important if there is no cooling system.
Mechanical loads are prohibited. This can cause the formation of microcracks and other damage.

Video about the restoration of lithium-polymer batteries.

Before using the universal charger you must:

Compare technical parameters.
Check capacity indicators. If you use limited chargers, it will be difficult to charge the power source.
Make sure the charger is working properly. After all, Chinese products may have defects.

If necessary, you can check how the old battery will charge.

Storage and disposal of polymer batteries

The service life of ion polymer batteries depends on compliance with storage rules.

Primary power sources do not require special storage conditions. It is enough to follow the manufacturers' recommendations.
The battery removed from the device is placed on a dry surface. In this case, it is necessary to minimize the likelihood of sunlight hitting the surface of the power source.
The likelihood of freezing increases if the battery is discharged. Therefore, premises with the required conditions are selected for storage.
Polymer batteries should be stored with a small charge (40–50%).
It is not worth using and storing lithium polymer batteries, whose voltage constantly decreases. Such devices must be recycled.
After long-term storage, the energy source must be inspected. Damaged or swollen batteries should be replaced.

The electrochemical system of polymer batteries is harmless. After all, during the preparation, environmental standards and requirements were taken into account. But the disposal of failed devices is mandatory. Such actions help preserve the environment. Failed sources are transferred to the appropriate organizations in the prescribed manner.

Modernized lithium polymer batteries are gradually replacing traditional power sources. And this is due to considerable capabilities, technical characteristics and an increased level of safety.