Detailed description lithium-ion 18650 batteries, making a device for charging with your own hands, the nuances of the application.

TEST:

1. What was the main disadvantage of the early 18650 battery models?

a) They exploded due to the metallic lithium inside - with frequent charges, accumulations appeared on the cell, leading to an explosion.

b) The battery was too bulky and inconvenient.

1. What problem have not the manufacturers of modern 18650 models got rid of?

a) The battery often overheats.
b) The battery quickly loses its charge when exposed to negative temperatures.

1. In which temperature range is it desirable to store the battery?

a) + 10 - + 25 - ideal performance. The battery cannot tolerate extremely cold or hot environments.

b) Store the battery at low temperatures when not in use.

c) At a temperature of + 30-45 degrees.

1. Why can't I purchase a charger made in China?

a) The case is too unreliable.
b) Parts of poor quality, correct assembly technology is not always followed.

1. At what level of charge is it desirable to store the battery?

a) 18650 storage should be carried out at a charge level that does not fall below 50%. Complete discharge cannot be performed.

b) Not less than 10%.

Answers:

1. a) The main disadvantage of the first models is explosion hazard. Lithium metal was overgrown with build-ups with frequent charges and a short circuit occurred, leading to an explosion of the battery.
2. b) Modern batteries do not tolerate low temperatures well - the charge drops very quickly.
3. a) + 10 - + 25 - ideal performance. Do not place the battery in any other environment.
4. b) Chinese manufacturers often use low-quality parts when assembling devices, so they fail. The correct assembly technology is not always followed.
5. a) If you plan to keep the battery without work for a long time, then make sure that the charge on it does not fall below 50%, otherwise the battery will deteriorate.

Lithium-ion owners accumulators The 18650 is faced with the question of how to charge it. Also, difficulties arise in the correct operation, people do not know exactly what such batteries are afraid of, how to increase the duration of their operation.

To independently assemble an electronic cigarette or flashlight, you definitely need to study all aspects work with a lithium-ion power supply.

Definition: Li-ion battery Is the battery electric current, which has become widespread among household electronic appliances since 1991. It was this year that Sony introduced the product to a wider market.

Answers to 5 frequently asked questions

1. What is lithium used for? ion batteries?

- As a power source. Such batteries are often used for various mobile phones, camcorders, laptops, for recharging electric vehicles or modern electronic cigarettes.

1. Do the models have disadvantages?

- The main drawback of the model was that the first developments literally exploded. This is due to the fact that manufacturers have placed inside an anode consisting of metallic lithium. When a large number of charges and discharges occur, formations appear on the anode, leading to the closure of the electrodes. As a result, a fire occurs, and then an explosion. On this moment this issue has been resolved.

1. How was the problem with explosions solved?

“To secure the structure, the scientists replaced the core with graphite, and got rid of the problem with explosions. But difficulties remained with the cathode caused by the cobalt oxide construction. If operational characteristics were violated, the explosions were repeated. That is why it was necessary to ensure that the device did not undergo recharging. It was extremely inconvenient for users to constantly monitor the charging level and the developers had to modify the device again. Modern models are safe. When developers began to use lithium-ferro-phosphate batteries, they managed to get rid of this problem. A modern device is produced in such a way that overcharging and overheating is impossible.

1. Are current models flawed?

- Charge is lost if the battery is exposed to cold temperatures.

1. If the battery is left unused for a long time, will it deteriorate?

- If you do not lower the rarefaction level below 50%, it will not deteriorate.

3 battery benefits

Lithium ion accumulators have a number of positive aspects due to which they gained popularity:

1. Extra large capacity battery.
2. Small self-discharge.
3. No special maintenance required.

Charging - 5 nuances

Look at the picture for the original charger device. Charger intended for lithium-ion batteries is very similar to the lead-acid type of battery. The difference is that the lithium-ion battery there are high voltages on each can and severe voltage tolerance requirements.

It is interesting! The battery is called a "can" because of the similarity to the aluminum cans in which soft drinks are dispensed.

Most Popular Items nutrition with this form - 18650. The battery got this name because of the size: diameter - 18 mm, height - 65 mm. When charging lead acid accumulators, slight inaccuracies in voltage indications are allowed. Nose lithium-ion devices everything is much more specific. When happens charger, and the voltage increases to 4.2 Volts, the voltage per cell must be stopped immediately. The error is only 0.5 volts.

There are a large number of Chinese chargers designed for batteries different materials... Without prejudice to performance, ionic batteries are charged with a current of 0.8 A. But the voltage in the bank will have to be very closely monitored. When the value is 4.2 Volts, immediately stop charging. But in the event that the bank is embedded controller, then there is no need to worry about it, as the device will do everything on its own.

Charging 4.2 Volts

As charger for a lithium-ion battery, a voltage regulator is used, current limited at the very beginning of charging. It is necessary to use extremely stable voltage, and current limiting at the very beginning of the charging process. Charging should be completed at the moment when the stable voltage is 4.2 Volts, there is no current, or its value is very small - in the region of 5-7 mA.

When a rod is placed in the battery graphite, then the voltage should not exceed 4.1 V per cell. If this rule is disregarded, the energy density will increase greatly, and the oxidation processes of the device will begin. As a result, the battery will be damaged. To avoid oxidation, modern models are equipped with additives - graphite there is no pure inside. But such models can still be found by chance.

How to properly charge Li-ion batteries. Parallel connection of batteries.

Homemade charger at home (do it yourself) - 1 circuit

For charging 18650 acquire universal charging, and constantly use a multimeter to find out desired parameters... But such a device is quite expensive. The minimum price is 2700 rubles.

Instead, you can spend just a few hours putting together a charger. device on one's own. The advantages of such an assembly are cheapness, reliability, automatic shutdown battery. All the parts used for assembly can be found in the garage of any radio amateur. If something is missing, you can buy it at your nearest radio store. You will have to spend a maximum of 300 rubles on components.

If schema correctly assembled, then there is no need for additional adjustment - it will be immediately ready for use.

You need to use the following wiring diagram:

Scheme

On the positive side, if you set stabilizer on desired radiator, then the battery is charged without fear that the charging will light up. And this cannot be said for sure about Chinese chargers who sin with this unpleasant consequence.

The principle of operation - 4 nuances

• to start battery it must be charged with a constant current, which is determined by the resistance of the resistor R4;
• after battery will receive a voltage of 4.2 Volts, the device switches to DC charging;
• when the current drops to minimum values, the LED will stop lighting;
• current charging lithium-ion battery, should not exceed 10% of the capacity of the entire battery. Thus, the service life of the batteries is increased. If resistor R4 is 11 ohms, then the loop current should be 100 mA. If the resistance is 5 ohms, then the charging current should be 230mA.

It is also important to know 3 nuances about "extending the life" of the 18650

1. If battery will need to be left without work for some time, then it is advisable to store the batteries separately from the device that they will power. If the cell is fully charged, then over time it will lose some of its charge. In the case when the cell is charged very little, or is completely discharged, then the performance may completely disappear. This is especially noticeable during the period of long hibernation.
2. Storage The 18650 should be carried out at a charge level that does not fall below 50%. Under no circumstances should the cell be fully charged and recharged. This equipment has no memory effect. Charging must be done until the charge is completely dry. Thus, the battery life will last.
3. Battery it is forbidden to leave in too cold or hot rooms. The suitable storage temperature is + 10 - + 25 degrees Celsius. If the battery is placed in the cold, not only will the operating time decrease, but the chemical system will also deteriorate. Everyone must have noticed that when using a mobile phone in winter, the charge battery falls sharply.

How to avoid 4 mistakes when using and charging a lithium-ion battery

1. If you decide to recharge the lithium-ion battery using a store charger, you will have to make sure that it is not made in China. Usually similar devices are assembled from the cheapest materials, and the required technology is not always observed in them. As a result, this can lead to very sad consequences: fire and explosion.
2. If you want to assemble it yourself device, then you need a current to charge the battery, which is 10% of the battery capacity. The percentage may be higher, but not exceed 20%.
3. When using ionic batteries, do not violate the rules of storage and use, otherwise overheating, fire and explosion may occur.
4. If you follow all the rules exploitation, as well as correct storage conditions, the battery life can be extended.

Top 3 Best 18650 Battery Chargers

For high-quality battery charging, you should purchase good devices, which is already loved by many users.

1. Nitecore Digicharger D4 - Suitable for charging multiple batteries at once. It is as easy to use as possible.
2. Nitecore i2 is one of best options modern devices. Clear and easy to use.
3. Basen B21 - universal device for different types batteries.

Features of charging lithium batteries and chargers for them

Modern man uses a variety of electronic gadgets. This is a laptop, mobile phone, tablet, camera and many others. Most of these devices are powered by lithium batteries. After all, we value them precisely because they are mobile devices. However, portability comes at the cost of constantly recharging the batteries. To do this, you need a lithium battery charger. In most cases, chargers are supplied with the device itself. This is the same laptop or phone power adapter. Ideally, of course, regular charging should be used for charging. But what to do if it is lost or out of order. You need to find the right charger. What to take into account, we will discuss in this article.

In the general case, the charger for must have a voltage of 5 volts at the output and a current whose value corresponds to (0.5─1) * SN. Cn is the nominal capacity of the battery. For example, for a lithium cell with a capacity of 2200 mAh, charging should provide a current of 1.1 amperes.

Most chargers from reputable manufacturers charge Li batteries in several stages. The first stage takes place at a constant current value of 0.2-1 C and a voltage of 4.1-4.2 V (here we mean the voltage per element or bank). This stage lasts approximately 40-50 minutes. The second stage is carried out at constant voltage. There are devices that use a pulse mode to speed up the charging process. For lithium ion systems with a graphite system, the voltage must be limited to 4.1 volts per cell.

If you use a voltage higher than 4.1 volts, you can increase the energy density of the battery. However, oxidative reactions start and shorten the battery life. In later models, this problem was eliminated with additives. And on them, the voltage during the charging process can be increased to 4.2 volts with a deviation of 0.05 per element.

If we talk about lithium batteries for industrial use and for the military sphere, then for them the chargers support a voltage of 3.9 volts. This ensures long term service and reliability.

If the charger delivers 1C current, then the battery will be charged in about 2─3 hours. When the full charge is reached and the voltage reaches the cut-off value, the current decreases sharply and amounts to several percent of the initial value.

It should be said that with an increase in the charging current, the charging time practically does not decrease. With more high current the voltage rises faster at the first stage of the process, but the second stage of recharging in this case takes longer.

There are chargers that can charge a lithium battery in about an hour. Such a charger for lithium batteries does not have a second stage and the battery is ready for operation after the completion of the first stage. The charge level of the battery cell will then be 70 percent. But, due to the nature of lithium-type batteries, this is not critical for them.

In the graph above, you can see three stages of charging a Li battery:

• First. The maximum possible (1C) charge current flows through the battery. This stage ends when the voltage rises to the threshold value;
• Second. The voltage remains at its maximum (4.1-4.2 volts), and the charging current decreases to 3 percent of the original value;
• Third. Compensating charge during storage (carried out approximately every 20 days).

During the storage phase for lithium batteries, trickle charging is not possible due to the fact that it leads to metallization of the Li. But short-term recharges direct current compensate for the loss of charge. This charging should be done when the cell voltage drops to 4.05 volts. The charging process stops at 4.2 volts.

And one more important point... Lithium battery cells are very sensitive to overcharging. Even with a slight overcharge, lithium metallization begins on the surface of the negative electrode. It is very active and interacts with the electrolyte. As a result of the reaction, oxygen is released at the cathode, and the pressure rises. As a result, cell depressurization, ignition and even a small explosion can occur.

In addition, if the voltage limit is constantly exceeded during charging, the service life lithium batteries decreases. Therefore, in most lithium batteries, in addition to the cells themselves, there is a protection board.

The board controls the process of charging and discharging cells at the lower and upper voltage limits. Temperature sensors are often used to trip elements at 90 degrees Celsius. Some types of batteries have a mechanical valve that opens when the pressure inside the case rises above a certain limit.

There are exceptions. For example, batteries with manganese in their composition do not have this protection. Manganese strongly inhibits metallization at the anode and the formation of oxygen. Therefore, such protection is not necessary.

All this must be borne in mind when choosing a charger. If you will charge the lithium cell directly without a controller, the voltage must be constantly monitored. But it is much better to use devices with automatic control or charge the battery through a protection board.

Chargers for various gadgets

Smartphone battery chargers

If you have lost a regular charger from your phone, the "frog" will help you. This is one of the most common devices. The charge got its name for its characteristic shape.

It's easy to use. The charger has 2 contacts adjustable in width: plus and minus. You need to set them in a position suitable for the battery being charged. Then the battery is inserted so that there is contact with its terminals, and is fixed by the upper clamping bar. Naturally, the polarity must be observed during installation. Then the device is inserted into a 220 volt socket and charged until the indicator shows the end of the process.

You will be able to familiarize yourself with the charger circuit which is perfect for lithium Li-Ion batteries.

At first, its author wanted to present a simple version on the lm317 microcircuit, but in this case, the charging must be powered from a higher voltage than 5 volts. The reason is that the difference between the input and output voltages of the lm317 microcircuit must be at least 2 volts. Charged voltage lithium ion battery is about 4.2 Volts. Therefore, the voltage difference is less than 1 volt. This means that you can come up with a different solution.

On Aliexpress you can buy a specialized board for charging lithium batteries, which costs about a dollar. Yes, it is, but why buy something that can be done in a couple of minutes. Moreover, it takes a month until you have the order. But if you decide to buy a ready-made one in order to use it right away, buy it in this Chinese store. In your store search, enter: TP4056 1A

The simplest scheme

Today we will consider options for a UDB charger for lithium batteries that everyone can repeat. The scheme is the simplest one you can think of.

This is a hybrid circuit, where there is voltage stabilization and current limitation of the battery charge.

Charging operation description

Voltage stabilization is based on the rather popular tl431 adjustable zener diode microcircuit. Transistor as an amplifying element. The charge current is set by the resistor R1 and depends only on the parameters of the battery being charged. This resistor is advised with a power of 1 watt. And all other resistors are 0.25 or 0.125 watts.

As we know, the voltage of one cell of a fully charged lithium-ion battery is about 4.2 volts. Therefore, at the output of the charger, we must set exactly this voltage, which is set by the selection of resistors R2 and R3. There are so many online programs for calculating the stabilization voltage of the tl431 microcircuit.
For the most accurate setting of the output voltage, it is advised to replace the R2 resistor with a multi-turn resistance of about 10 kilo-ohms. By the way, such a solution is also possible. The LED is used as a charge indicator, almost any LED, color of your choice will do.
The whole setup is reduced to setting the voltage at the output to 4.2 volts.
A few words about the tl431 zener diode. This is a very popular microcircuit, not to be confused with transistors in a similar package. This microcircuit is found in almost any pulse unit power supply, for example a computer, where the microcircuit is most often in the harness.
The power transistor is not critical, any medium or high power reverse conduction transistor is suitable, for example, from the Soviet ones, KT819, KT805 are suitable. From less powerful KT815, KT817 and any other transistors with similar parameters.

What batteries is the device suitable for?

The circuit is designed to charge only one can lithium battery... You can charge a battery of standard 18 650 and other batteries, you just need to set the appropriate voltage at the output of the charger.
If suddenly, for some reason, the circuit does not work, then check the presence of voltage at the control pin of the microcircuit. It must be at least 2.5 volts. This is the minimum operating voltage for an external source. reference voltage microcircuits. Although there are versions where the minimum operating voltage is 3 Volts.
It is also advisable to build a small test bench for the specified microcircuit in order to test it for operability before soldering. And after assembly, we carefully check the installation.

In another publication, there is a material about the improvement.

How to properly charge a lithium-ion battery and why do you need it at all? Our modern devices work thanks to the availability of autonomous power supplies. And it doesn't matter what kind of devices they are: electric smartphones or laptops. That is why it is so important to know the answer to the question of how to properly charge a lithium-ion battery.

A little about what a lithium-ion battery is

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

The advantages of these types of batteries

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

Important and interesting facts

A smartphone battery has its own specific features. Therefore, you need to know certain rules and be familiar with the corresponding instructions before starting to engage in the process of forced charging or discharging. It should be noted first of all that most batteries of this type are specially equipped with additional device control. Its use is due to the need to keep the charge at a certain level (which is also called critical). Thus, the control device built into the battery for a smartphone does not allow us to cross that fatal line, after which the battery will simply “die”, as service specialists like to say. From the point of view of physics, everything looks like this: in the opposite process (critical discharge), the voltage of the lithium-ion battery simply drops to zero. In parallel, the flow of current is blocked.

How to properly charge digital equipment based on this source of autonomous work

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

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

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

Terms of use

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

Rule one

It consists in what is not needed completely. It has already been said that such a procedure should be carried out only once every three months. Modern designs of these power supplies do not carry the "memory effect". Actually, therefore, it is better to have time to put the device on charge before it completely "sits down". By the way, it is quite remarkable that some manufacturers of corresponding products measure the service life of products in the number of cycles. High-end products are able to “survive” about six hundred cycles.

Second rule

It states that the mobile device needs a complete discharge. It should be done every three months for prophylaxis. Conversely, irregular and unstable charging can shift the nominal minimum and maximum charge marks. Thus, the apparatus in which this source is embedded autonomous work, begins to receive false information about how much energy is actually left. And this, in turn, leads to incorrect calculations of energy consumption.

Preventive discharge is designed to prevent this. When this occurs, the control circuit will automatically zero the minimum charge value. However, there are some tricks here. For example, after complete discharge it is necessary to "hammer" the power source to the eyeballs, holding it for an additional 12 hours. In addition to the usual electrical network and wires, we do not need anything else for charging in this matter. On the other hand, the battery's performance after preventive discharge will become more stable, and you can immediately notice it.

Third rule

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

Rule four

The price for which falls in the range from several hundred to several thousand rubles should be charged only with the help of original devices. This is less true for mobile devices, because their package (if you buy them in an official store) already includes adapters. But in this case, they only stabilize the supplied voltage, and the charger, in fact, is already built into your device. That, by the way, cannot be said about camcorders and cameras. This is what we are talking about, here the use of third-party devices when charging batteries can cause noticeable harm.

The fifth rule

Watch your temperature. Lithium-ion batteries can resist thermal stress, but overheating is detrimental to them. And low temperatures for a power supply are not the best that can be. Although the great danger comes precisely from the overheating process. Remember, the battery must not be exposed to direct sun rays... The range of temperatures and their permissible values ​​starts at -40 degrees and ends at + 50 degrees Celsius.

Charger for li ion battery , the diagram of which is given in this article, was developed based on the experience of designing such chargers, efforts to eliminate errors and achieve maximum simplicity. The charger features high output voltage stability.

Description of charging for lithium ion batteries

The main structural element is (IO1) - a voltage reference. Its stability is significantly better than admissible, and, as is known for lithium-ion batteries, this is very important characteristic when charging.

The TL431 element is used in this circuit as a current stabilizer in the operation of transistors T1 and T2. The charging current flows through R1. If the voltage drop across this resistor exceeds approximately 0.6 volts, there is a limitation of the current passing through the transistors T1 and T2. The value of the resistor R1 is equivalent to the charging current.

The output voltage is controlled by the aforementioned TL431 element. The value is determined by the divider of the output voltage (R5, R7, P1).

Components R4, C1 for noise suppression. It is very convenient to indicate the value of the charging current, using the LED1 LED. The glow shows how much current flows in the base circuit of the transistor T2, which is proportional to the output current. As the lithium-ion battery is charged, the brightness of the LED will gradually decrease.

Diode D1 is designed to prevent the discharge of the lithium-ion battery in the absence of voltage at the input of the charger. The battery charging circuit does not need protection against wrong connection polarity li-ion battery.

All components are housed on a single sided PCB.

Current sensor - resistor R1 consists of several resistors connected in parallel. Transistor T2 must be placed on the heatsink. Its size depends on the charging current and the voltage difference between the input and output of the charger.

The lithium-ion battery charger circuit is so simple that with proper installation of radio components it should work the first time. The only thing that may be required is setting the output voltage. For a lithium-ion battery, this is approximately 4.2 volts. When idling, transistor T2 should not be hot. The input voltage must be at least 2 volts higher than the required output voltage.

The circuit is designed for charging currents up to 1 ampere. If it is necessary to increase the charging current of the li-ion battery, then it is necessary to reduce the resistance of the resistor R6 and the output transistor T2 must be of increased power.

At the end of the charging process, the LED still glows a little, in order to eliminate this, you can simply connect a 10 ... 56 kOhm resistor in parallel with the LED. So when the charge current drops below 10 mA, the LED will stop glowing.

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