Lithium ion battery polymer. Lithium-polymer batteries: properties, assembly and charging

Battery production technology does not stand still and gradually Ni-CD (nickel-cadmium) and Ni-MH (nickel-metal-hydride) batteries are displaced in the battery market, based on the production of lithium technology. Lithium polymer (Li-PO) and lithium-ion (Li-Ion) batteries are increasingly used in various electronic devices as a current source

Lithium - silver-white, soft and plastic metal, solid sodium, but softer lead. Lithium is the easiest metal in the world! Its density is 0.543 g / cm 3. It can be treated with pressing and rolling. Lithium deposits are available in Russia, Argentina, Mexico, Afghanistan, Chile, USA, Canada, Brazil, Spain, Sweden, China, Australia, Zimbabwe and Congo

Excursion to history

The first experiments on the creation of lithium batteries began in 1912, but only six decades later, in the early 70s, they were first introduced into household devices. Moreover, I emphasize, it was exactly the batteries. Following this attempts to develop lithium batteries (rechargeable batteries) were unsuccessful due to the problems associated with ensuring their operation. Lithium, the easiest of all metals, has the greatest electrochemical potential and provides the greatest energy density. Accumulators 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 work (charge - discharge) of lithium batteries leads to changes in the lithium electrode, as a result of which thermal stability decreases and the threat of the outlet of the thermal state from under control appears. When this happens, the temperature of the element quickly approaches the melting point of lithium - and the rapid reaction begins with the ignition of the released gases. For example, a large amount of lithium batteries for mobile phones set in Japan in 1991, it was withdrawn after several cases of their ignition.

Due to the characteristic lithium of instability, the researchers turned their eyes towards non-metallic lithium batteries based on lithium ions. A little losing at the same time with energy density and having accepted some precautions during charge and discharge, they received more secure so-called lithium-ion (Li-Ion) batteries.

The energy density of the Li-Ion batteries is usually several times higher than the density of standard NiCD and NIMH batteries. Thanks to the use of new active materials, this superiority increases annually. In addition to the large capacity of the Li-ion, the battery during discharge behaves similarly to nickel batteries (the form of their discharge characteristics is similar and differs only by voltage).

Today, there are many varieties of Li-Ion batteries, and you can talk about the advantages and disadvantages of one or another type for a long time, but it is impossible to distinguish them in appearance. Therefore, we note only those advantages and disadvantages that are peculiar to all types of these devices, and consider the reasons that caused the emergence of lithium-polymeric (Li-PO) batteries.

Li-ion battery Everybody was good, but problems with ensuring the safety of its operation and the high cost led scientists to create a lithium-polymer battery (Li-POL or LI-PO).

Their difference between Li-Ion is reflected in the title and lies in the type of electrolyte used. Initially, in the 70s, a dry solid polymer electrolyte, similar to a plastic film and non-conductive electric current, was applied, but an exchanging ion exchange (electrically charged atoms or groups of atoms). The polymer electrolyte actually replaces the traditional porous separator impregnated with electrolyte, so that they have a flexible plastic shell, have a smaller weight, large current-matt 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 you to produce fine batteries of arbitrary shape. The minimum thickness of the element is about one millimeter, so that the equipment developers are free in the choice of shape, outlines and sizes, up to the introduction of it in fragments of clothing.

Main advantages

• Lithium-ion and lithium polymer batteries are superior to the energy intensity of nickel (NICD and NI-MH) batteries
• Low self-discharge
• High voltage of a single element (3.6-3.7V against 1.2V-1.4 in NiCD and NIMH), which simplifies the design - often the battery consists only of one element. Many manufacturers are used in various compact electronic devices (cell phones, communicators, navigators, etc.) It is such a single element battery.
• Thickness of elements from 1 mm
• Ability to get very flexible forms

disadvantages

• The battery is susceptible to aging, even if it is not used and simply lies on the shelf. For quite obvious reasons, manufacturers about this problem are silent. The clock begin to tick from the moment the batteries produced at the factory, and the decrease in the capacity is the result of increasing the internal resistance, which in turn is generated by oxidation of the electrolyte. As a result, the internal resistance will reach such a level when the battery can no longer give the accumulated energy, although it will be enough in the battery. In two or three years it often becomes unsuitable for use.
• Higher cost compared to NiCD and NI-MH batteries
• When using lithium polymer batteries, there is always a risk of their ignition, which can happen due to the closure of contacts, from incorrect charging, or mechanical damage to the battery. Since lithium burning temperature is very high (several thousand degrees), it can ignore the standing objects and cause a fire.

The main characteristics of Li-PO batteries

As mentioned above, lithium-polymeric batteries are superior to the energy intensity of NiCD and Ni-MH batteries several times. The service life of modern Li-PO batteries, as a rule, does not exceed 400-500 cycles charge-discharge. For comparison, the service life of modern NI-MH batteries with low self-discharge is 1000-1500 cycles.

Technology production of lithium batteries do not stand still and the above numbers at any time can lose the relevance, because Battery manufacturers with each month increase their characteristics due to the introduction of new technological processes of their production.

From the entire variety of lithium-polymer batteries commercially available, two main groups can be distinguished - quick-bit (HI DISCHARGE) and normal. They differ in each other with a maximum discharge current - it is indicated either in amperes, or in units of the battery capacity, indicated by the letter "C".

Li-Po batteries

The use of LI-PO batteries allows you to solve two important tasks - to increase device operation time and reduce the weight of the battery

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

Quick-bit Lithium polymer batteries are often called " power»- Such batteries are used to power devices with high current consumption. A vivid example of the use of "power" Li-PO batteries are radio-controlled models with electric motors and modern hybrid cars. It is in this segment of the market that the main competitive struggle of various Li-PO batteries occurs.

The only area where the lithium-polymer batteries is inferior to nickel - this is the supervice area (40-50c) discharge currents. For the price, in terms of capacity, lithium-polymer batteries are approximately as much as NiMH. But in this market segment there were already competitors - (Li-Fe), the production technology of which is developing with each day.

Charging Li-Po batteries

The charge of most Li-PO batteries is carried out by a fairly simple algorithm - from the 4.20V constant voltage source / element with a current limit in 1C (some models of modern power Li-Po batteries allow them to charge them in 5C). The charge is considered completed when the current falls to 0.1-0.2c. Prior to transition to the voltage stabilization mode at a 1C current, the battery is gaining approximately 70-80% of the tank. For complete charging, time is about 1-2 hours. The charger has sufficiently strict requirements for the accuracy of maintaining the voltage at the end of the charge - not lifting 0.01 V / bank.
From the charging devices presented in the market, two main types can be distinguished - simple, not "computer" chargers in the price category of $ 10-40, intended only for lithium batteries, and universal chargers in the price category 80-400 $, intended for servicing various types batteries.

The first, as a rule, only the LED charge indication, the number of cans and currents are displayed in them with jumpers or by connecting the battery to various connectors on the charger. The advantage of such charger is the low price. The main disadvantage - some of these devices do not know how to correctly determine the end of the charge. They define only the moment of transition from the current stabilization mode to the voltage stabilization regime, which is approximately 70-80% of the container.

In the second group of charge chargers, the possibility is much wider, as a rule, they all show the voltage, current, and the machine tank, which the battery "accepted" during the charge, which makes it possible to determine how much the battery is more accurate. When using the charger, the most important thing is to correctly set the desired number of cans in the battery and charge current, which is usually 1C.

Operation of LI-PO batteries and precautions

It is safe to say that the lithium-polymeric batteries are the most "gentle" of the existing, i.e. require mandatory compliance with several uncomplicated rules. We list them in descending order of danger:

1. Battery reload - charge to voltage exceeding 4.20V per can
2. Short circuit battery
3. Discharge currents exceeding the load capacity or leading a Li-PO battery-60 ° C
4. Discharge below voltage 3V per can
5. Battery heating above 60ºС
6. Depressurization of the battery
7. Storage in discharged

Failure to comply with the first three items leads to a fire, all others - to full or partial loss of container

From all this, you can draw the following conclusions:

• So that there is no fire, you need to have a normal charger and correctly set the number of charged cans on it
• It is also necessary to use connectors that exclude the possibility of short-circuit batteries and control the current consumed by the device in which the Li-Po battery is installed.
• It is necessary to be sure that your electronic device in which the battery is not overheated. At + 70 ° C in the battery begins to go "chain reaction", which turns the energy splashing into it in heat, the battery literally spreads, setting on everything that can burn
• If you close an almost discharged battery, then the fire will not be, it is quiet and peacefully "die" due to overlap
• Watch for the voltage at the end of the battery discharge and be sure to turn it off after work.
• Depressurization is also the reason for the release of lithium batteries. Inside the element should not fall air. This may occur when there is a damage to the external protective package (the battery is in the package in the package like a shrink tube) as a result of a blow, or damage to the sharp object, or with a strong overheating of the battery output when soldering. Conclusion - not to drop from a high height and solder gently
• Store batteries, judging by the recommendations of the manufacturers, it follows in a 50-70% state charged, better in a cool place at a temperature not higher than 30 ° C. Storage in the discharged state adversely affects the service life. Like all batteries, lithium-polymer has a small self-discharge.

Assembling Li-Po Batteries

To obtain high-current batteries or high containers, a parallel connection of batteries are used. If you buy a finished battery, then on the marking you can find out how many cans in it and how they are connected. The letter P (Parallel) after the number indicates the number of connected parallel to the cans, A S (Serial) - sequentially. For example, Kokam 1500 3S2P denotes the battery connected in series from three batteries pairs, and each pair is formed by two parallel with connected batteries with a capacity of 1500 mAh, i.e. The battery capacity will be 3000 mAh (with a connection parallel to the container increases), and the voltage is 3.7V x 3 \u003d 11.1V.

If you buy batteries separately, before connecting them to the battery, you need to equalize their potentials, especially the option of parallel inclusion, since one bank will start charging the other and the charging current may exceed 1C. Preferably, all purchased banks in front of the connection to discharge up to 3V current about 0.1- 0.2С. The voltage must be controlled by a digital voltmeter with an accuracy of not lower than 0.5%. This will ensure reliable battery functioning in the future.

Alignment of potentials (balancing) is also desirable to spend even on the collected corporate batteries before their first charge, since many companies that collect elements in the battery are not balanced before assembly.

Due to the fall in the capacity, as a result of operation, it is impossible to add new banks in succession to the old - the battery will be unbalanced.

Of course, the batteries of different, even close tanks can be connected to the battery - for example 1800 and 2,000 mAh, as well as use batteries in different manufacturers in one battery, since different internal resistance will lead to a battery unbalance.

When soldering should be accumulated, it is impossible to prevent overheating of the conclusions - it may disrupt the seal and for all "kill" the battery has not yet worked. Some Li-Po batteries are supplied with already soldered to the conclusions of the textolite printed circuit board for the convenience of placing wires. This uses excess weight - about 1 g per item, but to warm the places for the switching of wires can be much longer - the fiberglass is well conducted. The wires with the connectors should be fixed on the battery case, at least scotch, so that it is not necessary to accidentally take them off when multiple connected to the charger

Li-Po Battery Application Nuances

I will give a few more useful examples arising from previously said, but non-obvious at first glance ...

During the long exploitation of the battery, its elements due to the initial small spread of containers become unbalanced - some banks are "aging" before others and lose their capacity faster. With a greater number of cans in the battery, the process is faster. From here implies the following rule - it is necessary to control the capacity of each battery element..

In case of detection in the assembly of the battery, the capacity of which is different from other elements by more than 15-20%, it is recommended to refuse to use the entire assembly, or from the remaining batteries to solder the battery with a smaller number of items.

Modern chargers have built-in Balancer (Balancer), which allow you to charge all elements in the battery separately under clear control. If the charger is not equipped with a balancer, then it must be purchased separately and the charge of batteries is desirable to produce with its use.

An external balancer is a small board connected to each bank containing load resistors, a control circuit and a LED, showing that the voltage on this bank reached 4.17-4.19V. When the voltage is exceeded on a separate threshold element in 4.17V, the balance sheet closes the part of the current "on itself", not allowing the voltage to exceed the critical threshold.

It should be added that the balancer does not save on some cans in a unbalanced battery, it serves only to protect against damage to the elements when charging and the definition of "bad" elements in the battery.

The above refers to batteries made up of three elements and more, for two-bed batteries Balancars, as a rule, do not apply

By numerous reviews, the discharge of lithium batteries before 2.7- 2.8V quickens more delicately affects the containers than, for example, a reload to voltage 4.4V. Especially harmful to store the battery in the redefined state.

It is believed that lithium polymer batteries cannot be operated under negative temperatures. Indeed, in the specifications on the battery, the operating range of 0-50 ° C is specified (80% of the battery capacity is saved at 0 ° C). But nevertheless, use Li-Po batteries at negative temperatures, about -10 ... -15 ° C, you can. The fact is that you do not need to freeze the battery before use - put it in your pocket, where heat. And in the process of using, the internal separation of heat in the battery turns out to be at the moment a useful property, not allowing the battery to freeze. Of course, the recoil of the battery will be slightly lower than at normal temperature.

Conclusion

Considering how technical progress in the field of electrochemistry is moving, it can be assumed that the future behind lithium energy accumulation technologies, if they do not catch up with fuel cells. Wait and see…

The article uses the materials of the articles of Sergei Stepper and Vladimir Vasilyeva

Progress is going forward, and on the change of the NICD traditionally used (nickel-cadmium) and NiMH (nickel-metal hydride) we got the ability to use lithium batteries. With comparable weight of one element, they have a large, compared to the NiCD and NIMH capacity, in addition, the element voltage is three times higher - 3.6V / element instead of 1.2V. So for most models there is enough batteries from two or three elements.

Among the lithium batteries, there are two main types - lithium-ion (Li-ion) and lithium polymer (LiPo, Li-Po or Li-POL). The difference between them is in the type of electrolyte used. In the case of Liion, it is a gel electrolyte, in the case of Lipo, a special polymer saturated with a lithium-containing solution. But for use in the power plants of the models, lithium-polymer batteries were most common, so that later the conversation would go about them. However, the rigid separation here is very conditionally, since both types differ mainly used by electrolyte, and everything that will be said about lithium-polymer batteries, almost fully applies to lithium-ion (charge, discharge, features of operation, safety, safety ). From a practical point of view, only the moment that lithium polymer batteries currently provide higher discharge currents at the moment. Therefore, in the model market, they are mainly offered as a source of energy for power plants.

Main characteristics

Lithium-polymer batteries are superior to the NiCD energy intensity of 4-5 times, NiMH is 3-4 times. The number of operating cycles of 500-600, with discharge currents in 2C to loss of a capacity of 20% (for comparison - NiCD 1000 cycles, NiMH - 500). Generally speaking, any data on the number of working cycles is still very little and to the characteristics given in this case must be critical. In addition, their manufacturing technology is improved, and it is possible that the numbers are currently different for this type of battery. Just like all the batteries, lithium are susceptible to aging. After 2 years, the battery loses about 20% of the tank.

From the entire variety of power lithium-polymer batteries commercially available, two main groups - fast-sided (HI Discharge) and ordinary ones can be distinguished. They differ with each other with a maximum discharge current - it is indicated either in amperes, or in units of the battery container, denoted by the beech "C". For example, if the discharge current is 3c, and the battery capacity is 1 Ah, then the current will be equal to 3 A.

The maximum current of the discharge of ordinary batteries, as a rule, does not exceed 3c, some manufacturers indicate 5C. Fast-disconnect batteries allow the discharge current to 8-10s. Such batteries are somewhat heavier than their low-voltage fellows (by about 20%), and in the title, after numbers of the capacity, there are HD or HC letters, for example KKM1500 - a conventional battery with a capacity of 1500 mAh, and KKM1500HD is a quick-disconnerable. I want to immediately make a small remark for fans of experiments. In the household appliance, fast-sized batteries do not apply. Therefore, if you visit the idea to get a cheap battery from a cell phone or camcorder, then it is difficult to count on a good result. Most likely, this battery will die very quickly due to the violation of the provided operating modes.

Application and cost

The use of lithium polymer batteries allows you to solve two important tasks - to increase the operation time of the motor and reduce the weight of the battery.

When replacing the battery 8.4 V NimH 650 mAh with two ordinary, non-fast-disconnect lithium batteries with a capacity of 2 a * h, we obtain a battery 3 times greater tank, lighter at 11 g and with a slightly smaller voltage (7.2 volts)! And if you use fast-disconnect batteries, then the big aircraft can fly, not yielding in the energy transport of the DVSU. In confirmation of this, the 7th place in the world championship in the flight models F3A was taken by an American on an electroletter. And it was not a small buzz, but a normal two-meter aircraft, like the other participants who had models with internal combustion engines!

Lithium-polymer batteries on small helicopters, such as Piccolo or Hummingbird, such as Piccolo or Hummingbird, also have proven, even when using a standard collector motor, the flight time on two banks with a capacity of 1 Ah is more than 25 minutes! And when replacing the motor to the uncoolette - more than 45 minutes!

And, of course, lithium batteries are simply indispensable when it comes to indoor aircraft weighing 4-20 g. In this area, the NiCD cannot be compared with them - simply do not have such batteries (for example, weight 45 mAh banks - 1 g, 150 mAh - 3.2 d), which, at such a small weight, would give the necessary power - even if 1 minute!

The only area where the lithium polymer batteries is inferior to Ni-Cd is the super-high (40-50c) discharge current area. But progress goes ahead, and maybe in a couple of years we will hear about new successes in this area - because 2 years ago, no one has heard about fast-sided lithium batteries ...

Here, for example, the main characteristics of Kokam Lipo batteries:

Name	Capacity, Mah.	Dimensions, mm.	Weight, G.	Maximum current
Kokam 145.	145	27.5x20.4x4.3.	3.5	0.7A, 5C.
Kokam 340shc.	340	52x33x2.8	9	7a, 20s
Kokam 1020.	1020	61x33x5.5.	20.5	3a, 3s
Kokam 1500hc.	1500	76x40x6.5.	35	12a, 8c
Kokam 1575.	1575	74x41x5.5.	32	7A, 5C.

For the price, in terms of capacity, lithium-polymer batteries are approximately as much as NiMH.

Manufacturers

Currently, there are several manufacturers of lithium polymer batteries. The leader in the number of accumulators produced and one of the first in quality is Kokam. Thunder Power, I-Rate, E-Tec, and Tanic are also known (presumably, this is the second name Thunder Power or this is one of the vendors of Thunder Power under its name). You can watch Kokam types on www.fmadirect.com, batteries of different manufacturers are offered at www.b-p-p.com and www.lightflightrc.com.

There is also a Platinum Polymer offered at www.batteriesamerica.com, presumably - this is another name I-Rate.

The range of batteries capacity is very wide - from 50 to 3000mach. To obtain large capacities, a parallel connection of batteries is used.

Form all batteries are flat. As a rule, their thickness is less than 3 times the shortest side, and the conclusions are made with a short side in the form of flat plates.

I-Rate, as far as I know, there are no quick-sided batteries yet, and their batteries have one feature: one of the electrodes they have aluminum, and to solder it is problematic. This makes them uncomfortable when self-assembled batteries.

E-tec batteries are something average, they are not claimed as fast-sided, but the current of their discharge is higher than that of the usual - 5-7c.

The leaders in popularity are Kokam and Thunder Power, and Kokam is mainly used in lungs and medium-sized models, and Thunder Power on medium, large and giant (more than 10 kg!). Obviously, this is due to the price and the presence in the assortment of powerful assemblies - up to 30 volts and 8Ah capacity. Next comes tanic and e-tec, but about I-RATE mentions are small. Platinum Polymer is popular for some reason only in America, and it is used almost exclusively on slow slooflara.

Charging lithium polymer batteries

The charge of batteries is carried out by a fairly simple algorithm - charge from the source of a constant voltage 4.20 volt / element with a current limitation in 1C. The charge is considered completed when the current falls to 0.1-0.2c. After transition to the voltage stabilization mode at a current of 1s, the battery is gaining approximately 70-80% of the capacity. For complete charging, time is needed about 2 hours. The charger has sufficiently strict requirements for the accuracy of maintaining the voltage at the end of the charge - no worse than 0.01 V / can.

From the charging devices presented in the market, it is possible to highlight the main types - simple, not "computer" chargers, in the price category 10-40 $, intended only for lithium batteries, and universal - in the price category 120-400 $, intended for various types of batteries, Including for Lipo and Li-Ion.

The first, as a rule, have only LED charge indication, the number of cans and currents are displayed in them with jumpers. The advantage of such charger is the low price. The main disadvantage - some of them do not know how to properly show the end of the charge. They show only the moment of transition from the current stabilization mode to the voltage stabilization regime, which is approximately 70-80% of the container. For a complete completion of the charge, you should still wait 30-40 minutes.

In the second charger group, the possibility is much wider, as a rule, they all show the voltage, current and capacity (mAh) that the battery "accepted" during the charge, which allows you to more accurately determine how the battery is accurately charged.

When using the charger, the most important thing is to correctly set the desired number of cans in the battery and the charge current on the charger. The charge current is usually equal to 1C.

Operation and precautions

It is safe to say that the lithium-polymeric batteries are the most "delicate" batteries from existing, that is, they require mandatory compliance with several simple, but mandatory rules, due to non-compliance with or a fire, or the battery "dies."

We list them in descending order of danger:

1. The charge up to voltage exceeding 4.20 volts / bank.
2. Short closure of the battery.
3. Slit currents exceeding the load capacity or the heating battery above 60 ° C.
4. Discharge below voltage 3.00 volt / bank.
5. Battery heating above 60 ° C.
6. Rackets of battery.
7. Storage in discharged.

Failure to comply with the first three points leads to a fire, all others - to full or partial loss of container.

From all this, you can draw the following conclusions:

In order not to be a fire, you need to have a normal charger and correctly set the number of charged cans on it. It is also necessary to use connectors that exclude the possibility of a short circuit of the battery (because of this, my friend burned the table on which batteries, and the curtain) charged and control the current consumed by the motor to the "full gas". In addition, it is not recommended for the model to close the batteries from all sides of the flow of air flow, and if it is impossible, you should provide special cooling channels.

In cases where the current consumed by the engine is more than 2C, and the battery is closed on the model from all sides, after 5-6 minutes of the motor operation should stop it, and then pull out and touch the battery is not too hot. The fact is that after heating above a certain temperature (about 70 degrees) in the battery begins to go "chain reaction", which turns the energy splashing into it in heat, the battery literally spreads, filling all that can burn.

If you close an almost discharged battery, the fire will not be, it will die quietly and peacefully because of the redistribution ... From here it follows the second important rule: follow the voltage at the end of the battery discharge and be sure to disconnect the battery after work!

Some speed controllers (Jeti sin it.) Do not stop current consumption after turning off the standard switch. What made Czechs take such a strange decision - I do not know. But the fact remains the fact, almost all models of controllers for the Jetti bulk motors (including the new "Advanced" series), in which there is a BEC, that is, the power supply stabilizer and power supply machines do not provide a full de-energization of the circuit with a regular switch. Only the receiver and servos are disconnected, and the controller continues to consume a current of about 20 mA. This is especially dangerous, as it is not clear that the meal is included, the cars are standing, the engine is silent ... And if you forget about the connected battery for a day, it turns out that it is possible to say goodbye to him - does not like lithium deep discharge.

Of course, it should be remembered that the engine controller should be able to work with lithium batteries, that is, to have an adjustable engine disconnection voltage. And do not forget to program the controller on the desired number of cans. However, a new generation of controllers appeared now, which automatically determine the number of connected cans.

The depressurization is another reason for the release of lithium batteries, since air should not fall inside the element. This can occur when there is a damage to the external protective package (the battery is in the package in the package like a shrink tube), as a result of impact or damage to a sharp object, or with a strong overheating of the battery output when soldering. Conclusion - not to drop from a high height and soldering gently.

Storage of batteries, judging by the recommendations of the manufacturers, should be made in a 50-70% state charged, better in a cool place, at temperatures not higher than 20 ° C. Storage in the discharged state adversely affects the service life - like all batteries, the lithium polymer has a small self-discharge.

Battery assembly

To obtain high-current batteries or high containers, a parallel connection of batteries is used. If you buy a finished battery, then on the marking you can find out how many cans in it and how they are connected. The letter P (Parallel) after the number denotes the number of connected parallel to the cans, and S (Serial) is selected. For example, "Kokam 1500 3S2P" refers to a battery connected in series from 3 pairs of batteries, and each pair is formed by 2-parallel with connected batteries with a capacity of 1500mach., That is, the battery capacity will be 3000mach (with a connection parallel to the container increases), and voltage - 3.7 * 3 \u003d 11.1V ..

If you buy batteries separately, before connecting them to the battery you need to equalize their potentials. This is especially true of the option of parallel inclusion, since the one bank will start charging the other, and the charging current may exceed 1C. It is desirable to discharge all purchased banks before the compound to 3 volts 0.1c - 0.2c. The voltage must be controlled by a digital voltmeter with an accuracy of not lower than 0.5%. This will ensure reliable battery functioning in the future.

Alignment of potentials (balancing) is also desirable to spend even on the collected corporate batteries before their first charge, since many companies that collect elements in the battery are not balanced before assembly.

Due to the fall in the capacity, as a result of operation, it is impossible to add new banks in succession to the old - the battery will be unbalanced.

Of course, the batteries of different, even close tanks can also be connected to the battery - for example, 1800 and 2,000 mAh, as well as use batteries in different manufacturers in one battery, since various internal resistance will lead to battery unbalance. When soldering should be accurate, it is impossible to allow overheating of the conclusions, it may disrupt the sealing and the battery has not yet had time to fly forever. Some types of Kokam batteries are supplied with already soldered pieces of printed circuit board to conclusions, for the convenience of placing wires. This uses excess weight - about 1g per item, but to warm the places for the switching of wires can be much longer - the fiberglass is well conducted heat. The wires with the connectors should be fixed on the body of the battery, at least scotch, so that it is not necessary to accidentally take off the root.

Nuances of application

So, we emphasize once again the most important points related to the use of lithium polymer batteries.

• Use a normal charger.
• Use connectors that exclude the possibility of closing the battery.
• Do not exceed the permissible discharge currents.
• Follow the accumulator temperature in the absence of cooling.
• Do not discharge the battery below Voltage 3 V / Bank (Do not forget to disconnect the battery after the flight!).
• Do not expose the battery.

We give a few more useful examples arising from previously said, but unmarked at first glance.

When using collector motors, it is necessary to prevent situations where the motor is stored (for example, the model lies on Earth), and on the transmitter the total gas is given. The current is too large at the same time, and we risk blew up the battery (if the motor or regulator does not burn before). This problem has been repeatedly discussed in the RC Groups forums. Most controllers for collector motors are turned off the motor when the signal is lost from the transmitter, and if your regulator can do it, I would advise you to turn off the transmitter if the model fell, for example, in the grass is far from you, - less risk when looking for a model to pinch a gas handle On the drive of the transmitter and not to notice this.

During the long exploitation of the battery, its elements due to the initial slight spread of containers become unbalanced - some banks are "aging" before others and lose their capacity faster. With a greater number of cans in the battery, the process is faster.

It follows the following rule - sometimes it is necessary to control the capacity of each battery element separately. To do this, you can measure its voltage at the end of the charge. How often? Especially this is still difficult to install - too little operation experience has been accumulated. As a rule, it is recommended to be recommended by approximately 40-50 cycles after starting operation times in 10-20 cycles to check the voltage of battery elements when charging to identify "bad cans".

It is not recommended to "plant at zero" battery, chasing the motor until it stops rotating at all. A new battery does not hurt such an appeal, but for a bit unfailed - this is an extra risk to discharge the most "bad bank" below 3 volts, which is why it will further lose the container.

When the tanks differ more than 20% - such a battery without special measures to charge the whole entirely!

To automatically balancing battery items, the so-called Balancer (Balancer) is used. This is a small board connected to each can, containing load resistors, a control circuit and a LED, showing that the voltage on this bank reached 4.17 - 4.19 volts. If the voltage is exceeded on a separate threshold element at 4.17 volts, the balancer closes a portion of the current "on itself", without allowing the voltage to exceed the critical threshold. Upon simultaneity of ignition, the LEDs can be seen which banks have a smaller capacity - the LED will sound first on their balancer. One important additional requirement is made to the balancers consumed by them from the battery in the "waiting" mode should be small, it is usually 5-10 μA.

It should be added that the balancer does not save on some cans in a unbalanced battery, it serves only to protect against damage to the elements when charging and the means of indicating the "bad" elements in the battery. The above refers to batteries composed of 3 or more elements, for 2 beds, the balancers are usually not used.

It is believed that lithium polymer batteries cannot be operated under negative temperatures. Indeed, in the specifications on the battery, the operating range is 0-50 ° C (at 0 ° C 80% of the tank is saved). But nevertheless, it is possible to fly on them at temperatures of about -10 ...- 15 ° C. The fact is that it is not necessary to freeze the battery before flying - put it in your pocket, where heat. And in the flight, the internal separation of heat in the battery turns out to be at the moment a useful property, not allowing the battery to freeze. Of course, the recoil of the battery will be slightly lower than at normal temperature.

Conclusion

Considering how technical progress in the field of electrochemistry is moving, it can be assumed that the future behind lithium-polymeric batteries - if they are not caught up with fuel cells. As the demand for batteries and increase their release, the price will inevitably fall, and then lithium will become finally as common as NiMH. In the West, this time is already half a year, at least in America. The popularity of electroles with lithium polymer batteries is growing. I would like to hope that the insane motors and controllers will also cheat towards them, but in this area the progress of price reduction is moving less rapidly. After all, only two years ago, I was asked a question in the forum - "Does anyone actually fly to Brushless?". And about lithium batteries, then mention was not at all ...

In general, we will live in - see.

Without normal battery work, the whole point is lost in the mobile device. The user turns out to be tied to the power grid and cannot be in touch during movement. In the company "Store-detail.ru" you can buy a lithium-polymer battery and solve problems with a quick discharge device.

How to order a lithium-polymer battery in the store-detail.ru

Want to quickly buy Li-Pol batteries and do not wait for the supply of spare parts? Contact our store. We are suppliers of leading service centers and spare parts stores, and retail buyers from all over the country are preferred.

Our company is not the first year selling and cooperates with the manufacturers of equipment directly. We specialize in the supply of original high quality spare parts. This guarantees the client uninterrupted battery operation.

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

Our company seeks to simplify the procedure for issuing an order as much as possible. To buy a polymer lithium-ion battery, the client does not need to spend time and come to our office. All questions will be quickly resolved through the site, email or by phone.

You can find out the exact cost of the details on our website. Store managers constantly update the range, cost information and residues.

The company "Store-detail.ru" cooperates with legal entities and individuals. Payment for orders can be made through popular services and payment systems without leaving home.

Delivery of lithium polymer batteries for smartphones is made through courier services, transport companies or Russian Post. Also, the goods can be taken at a convenient time independently from our warehouse.

Lithium polymer batteries appeared on the market not so long ago, but already serve as a power source for many gadgets. These batteries are used in smartphones, tablets, laptops, children's toys and other techniques.

Batteries are gradually improving, old errors and flaws are corrected. But still lithium polymer batteries fail, and sometimes can explode. Below will be considered how to avoid premature breakdowns, where to buy, as well as the features of this type of batteries.

Li-Po Battery is one of the types of lithium batteries. The development of polymer batteries was based on lithium-ion batteries. They use a liquid electrolyte, which is why some problems occur during operation.

The main purpose of the specialists was to get rid of the old electrolyte, as he caused a lot of difficulties.

In addition, several changes were made in the principle of battery operation.

To understand what lithium-polymer batteries differ from others, you need to figure out two main concepts:

1. The electrolyte is an acid solution conductive electric current. Unlike conventional conductors, there are positively charged ions.
2. The polymer is a substance that consists of a chain of repeating monomers (group of molecules).

So, what did scientists change in lithium-ion batteries? First, the electrolyte became solid. Secondly, a polymer was used as an electrolyte. Hence the name of these batteries.

In this case, the polymer is very thin, looks like a film. The polymer is no longer conducting the current, but it remains the property of the ions.

Thus, scientists received an electrolyte and separator in one piece of polymer.

The electrochemistry today is developing rapidly, new changes in the Li-Po design are constantly introduced. For example, recently in batteries were added robust electrolytes, which contain lithium ions.

Features Li-Po

The data that is written below is constantly changing, as the progress in electrochemistry does not stand still.

All characteristics are relevant only in 2019. In addition, they may vary, depending on the battery and manufacturer.

Main characteristics:

1. Energy intensity - measured in Mah (Milliamper per hour). If you recall the school course of physics, then the ampere is the power of the current. The clock in this case, characterize the time during which this battery maintains the required current. To understand the essence of the characteristics, take the usual battery from the smartphone to 4000 mAh, for example. Within one hour, such a battery gives a current of 4000 mA. If you take 4 hours, the current will be about equal to 1000 mA and so on.
2. The following characteristic is the number of discharges and charges, pay attention to it. This number determines how long the battery lives. Li-Po have not so many cycles. The norm for these AKB 400-500 cycles. When the battery will work out its 500 cycles, it can be thrown out. Ni-MH batteries have a minimum of 1000 cycles.
3. Input and output voltage. Input is a voltage that should be in the outlet. The output is the voltage that gives the battery. Most often, these two characteristics are equal, but there are exceptions.

Proper operation

Lithium polymer batteries are very gentle. There are many reasons due to which the battery fails.

Failure to comply with the rules of operation leads to a fire and complete malfunction.

Let's discern how to use lithium polymer batteries so that they will serve for a long time.

Operating Rules:

1. You can not allow the recharge of the battery, that is, the voltage should not exceed 4.2 volts. Due to the recharge, bloated may occur.
2. Short circuit.
3. Serve a current to a battery that exceeds the allowable rate.
4. Strong overheating (above 60 degrees).
5. Damage to the case and depressurization.
6. Store lithium polymer batteries in a discharged state.

Because of the first three, the reasons often arise a fire. To prevent this, use only serviceable chargers. A short circuit will save the correct connector in which there is protection against closure.

It is also necessary to control the current consumed by the device in which the lithium polymer battery is.

Battery overheating occurs due to the fact that the device itself, heating, heats up and Li-Po Akb.

If the battery temperature reaches 70 degrees, then the energy stored in the battery begins to turn into heat, thereby increasing the and without the temperature. At the same time, the battery begins to upload everything around. Especially from this suffer smartphones with lithium-polymer batteries and laptops.

It is believed that Li-Po cannot be used at negative temperatures. Despite the fact that the range in which the battery is working normally, is set from 0 to 50 degrees, it is possible to use at minus temperatures.

The main thing is not to fervor the battery.

Keep it warm, for example in your pocket. The inner heat of the battery will not allow the battery to cool. Of course, in the cold, the return will be slightly lower than when using the battery heat.

What are the advantages and disadvantages of lithium polymer batteries

1. In polymeric batteries a large electric capacity.
2. The thickness of the batteries reaches one millimeter.
3. The shape of the housing can be any.
4. If the battery is discharged, the voltage falls not as much as in other batteries.
5. Li-Po has no memory effect. If briefly, the memory effect is the loss of a significant battery capacity.
6. The battery can operate in a rather large range of temperatures (from -20 to 40 degrees).

• if the ambient temperature is below -20 degrees, the battery is quickly discharged;
• big value.

Battery assembly with your own hands

To assemble the battery itself, you need to buy batteries, or in the spacious - banks. To build, you need to be able to solder and understand the basic concepts of electronics.

To assemble the battery, all purchased banks must be connected in parallel. In order to determine the number of cans in the purchase battery, you need to look at the label. It is written on it not only the number of cans, but also the number of cans connected in series and in parallel.

Usually, the letter P indicates the number of cans connected in parallel, and the letter S is connected in series. For example, 3S2P is indicated on the package. It is deciphered so: under the case there are 3 rows of batteries, connected in series, in each row 2 cans.

If you use batteries that bought separately, before connecting them between themselves, the level of potentials on the stamps should be.

If this is not done, then the cans will start charging each other, which is why the current will arise more than 1C.

Also, before the connection, it is necessary to discharge all the banks so that the voltage is 3V, the current 0.1-0.2c. Especially all of the above applies to a parallel compound. The voltage is measured by a digital voltmeter, otherwise inaccuracies may occur.

Many manufacturers are not balanced banks to speed up and save on the production of the battery, so the balancing will be better spent independently.

To avoid the battery depletion in the future, in no case you can not add new items in the battery sequentially old.

To the unbalance can be operated by cans with different capacity, even if the difference between the values \u200b\u200bis small. For example, 1800 Mah and 2000 Mah. Different manufacturers have accumulators with different voltages, and this leads to unbalance.

When all batteries are purchased, you can start a soldering elements. Of course, you can come up with a scheme for the location of the elements on your own, but it is best to take ready.

In order not to overheat the exits and tightness of the banks, we solder carefully, otherwise the battery will fail, without even working.

You can purchase a special textolite printed circuit board on which it will be more convenient to unwind the wires. It is soldered to each bank. This adds a small weight of the bank (about 1 gram), but it becomes much more convenient to solder, as the fiberglass does not spend the heat and heat the warmness longer.

For balancing, a special fee is used, which contains load resistors, a control circuit, as well as a LED that will light up if the voltage is above 4.2V.

If the voltage exceeds this value, the board closes part of the current, which does not allow it to grow further. Such a fee must be soldered to each bank.

Proper charging Li-Pol

Battery charging is a simple matter. Just only the DC source, with a voltage of 4.2V. The current must be in 1C, although many modern models can withstand as much as 5c.

The full charge of the battery takes 1-3 hours, depending on the model and its characteristics.

Also, the charging of the battery can be stopped when the current falls to 0.1c. Before the batteries proceed to the stabilization mode, they type 60-80% of the energy from the entire capacity, with a constant current in 1C.

For proper charging, you must carefully select a charger. The voltage that the charger gives must be 0.01 on the bank.

There are two types of charging on the roar. The first is budget devices, cost from 10 to 50 dollars, are intended only for. The second is universal charging devices that are suitable for different equipment. Of course, they are much more expensive, from 80 dollars.

Cheap charging has no indicator showing current, voltage, charging time. The number of cans and the required current is set using jumpers or connect the charger to different connectors on the device.

Plus a cheap option in a low price. A minus such charging lies in the fact that they do not know how to accurately determine when you need to stop charging. All they can determine the moment of transition from stabilization of current to stabilization of the voltage. But, as a rule, the battery at that moment is charged only by 80%.

The second type of charger has more advantages than the first. They allow you to immediately find out the tension, current, the charge that was "transferred" to the battery in the process.

Conclusion

Over the past few years, lithium polymer batteries have changed a lot. Many people suggest that they are worth the future of electrochemistry. Although fuel energy sources appear on the market.

Difference betweenlithium-ionic andlithium polymer Battery types significantIf the polymer material acts as an electrolyte. Here you will learn the features of each type of battery and can make the right choice..

Running upwards, hurry to calm you - when buying a smartphone, tablet or laptopthe type of battery inside you will meet the same. And so that there is no one -Li-ion or Li-Po This will affect the time of operation and the characteristics of the device as a whole..

For example, a processor model or firmware version for the overall autonomy of a mobile gadget (keep in mind that it is not about tools) much more important than the battery type. Choose the most capacious battery and read feedback from real users.

Differences of lithium-ionic from lithium-polymer batteries

In all well-known smartphones, tablets, laptops, smart watches and other portable gadgets, the most suitable battery is calculated at the design stage at the engineering design phase. Manufacturers last years with special diligence seek to introduce the latest technologies for energy saving.

Sometimes developers manage to achieve the maximum lengthy cycle of autonomy. But in favor of the conceptual features of the future product (for example, a thin case or a huge camera without increasing the dimensions), even the coolest savings saving systems can be "strangled".

Therefore, it remains to buyers to compromise and choose the characteristics that are suitable for specific purposes. We go hiking or traveling - choose a long battery life to the detriment of dimensions and graceful appearance. Do you like to lay out the phone on the table in an expensive restaurant? Then we take it to it as an accessory - let it work less, but once again emphasizes the status of the owner.

Battery type (lithium-ion and lithium polymer) It does not affect the evaluation of the gadget - this is part of engineering calculation. Under the selected concept, where there is a choice between, relatively speaking, the design "simpler and cheaper" or "more complicated, but more expensive." If you want to independently determine the most endless apparatus among competitors, it is better to turn to professional reviews or at least reviews of real users. This information will tell you much more about the quality of the battery than its belonging to lithium-ion or lithium-polymer technology.

It doesn't matter what type is posted in a mobile device, just do not worry about it!

Here is the fact of the experts of "Battery University" - in modern gadgets are practically not found polymer Lithium Batteries, we are offered lithium-ion polymer batteriesin which applied laminated shell Instead of tough buildings, like ordinary lithium-ion batteries.

Most often, the lithium-polymer battery is called a lithium-ion battery in the elastic polymer shell with compact dimensions.

You wondered why manufacturers Li-Ion Polymer on some batteries (for example, on iPhone and other smartphones)? Now you know that it actually happens here - due to the shortened names, the difference between the lithium-ion and lithium-polymer battery when it comes to portable electronics, in fact minimal. Let's focus on this.

Pluses of lithium-ion (Li-Ion) batteries

+ High density
+ No memory effect
+ low cost