Li-ion and Li-polymer batteries in our designs. Li-ion and Li-polymer batteries in our designs Charging schemes for li-ion batteries

http://4pda.ru/forum/index.php?showtopic=64541&st=1140

The chip looks like this:
.
The wiring diagram is as follows:

Charger lithium batteries

http://radiokot.ru/forum/viewtopic.php?f=11&t=114759

http://cds.linear.com/docs/en/datasheet/405442xf.pdf

http://www.ti.com/lit/ds/symlink/lm3622.pdf
http://dlnmh9ip6v2uc.cloudfront.net/dat ... TP4056.pdf

Forum on lithium batteries.

http://radioskot.ru/forum/2-846-2

The device circuit is very simple. When connected to USB port computer after pressing the "Start" button, the charging process begins. Three 1.6 ohm resistors serve as a current limiter and as a current sensor. The current flowing through them creates a voltage drop, which, when applied to the T2 base, keeps it open. As a result, the LED lights up and opens field-effect transistor T1. I removed the transistor from the protection board from the old one lithium battery, but it can be easily replaced with such a common transistor as IRLML2502. Current will flow into the battery until the voltage across it reaches 4.25V. At this voltage, the comparator of the protective board located inside each battery is triggered to mobile phones and cameras. The current in the charging circuit drops to zero, T2 closes and de-energizes the LED and gate T1.
The device goes into an inactive state and does not consume current from either the USB or the battery.

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http://radioskot.ru/forum/2-846-7

chaos_84, I posted this diagram, but the diagram is not mine, I have been successfully using this charger for about 2 years specifically to charge a block of 3 18650 lithium cans. Now, according to the diagram itself, a current stabilizer is assembled on the lm317, which will limit the maximum charge current, pulsed on lm2576 regulated source voltage is 12.6V, but the so-called balancer is assembled on the op-amps; the LEDs indicate the balancing process.

LI-ION BATTERY CHARGING MODULE ON TP4056 CHIP FROM CELESTIALLY

I received this very useful thing in the mail today. This is a small board containing a controller charge Li-Ion TP4056 batteries (Datasheet) The microcircuit has an indication of the charging process and turns off the battery itself when the voltage reaches 4.2 V. Judging by the diagram from the datasheet, the microcircuit has an input for connecting the battery thermistor. But on the board, the first leg of the microcircuit sits on the ground and only the power pins are available to connect the battery. The charge current depends on the value of the resistor Rprog on leg 2 of the microcircuit. On the board that came to me there is a 1.2 kOhm resistor. Which, judging by the table from the datasheet, corresponds to a charge current of 1000mA With this current, my dead battery (from Nokia in the photo) was charged in about an hour from an initial voltage of 3.4 to 4.19 Volts. The charger input was supplied with 5 volts from the USB computer. I touched it and nothing got hot. I was afraid that at maximum current the battery would heat up, especially since Feedback

absent. But nothing happened. At the first start, nothing exploded and did not get warm during the entire operation :) In general, my impressions were that I liked the controller, and primarily for the price. For $1.5 we get a full-fledged controller with indication and in a ready-made design, convenient for use in your projects.

For those who are interested, here is the link to the lot http://www.ebay.com/1497.l2649

http://www.rlocman.ru/forum/showthread.php?t=11538

http://shemu.ru/zarydnoe/169-easy-ch...-from-usb.html

http://www.hobbielektronika.hu/kapcs...sor_tolto.html

Parallel connection of Li-Ion batteries of different capacities

http://forum.fonarevka.ru/showthread.php?t=15615 Well then. It turns out that a number of people still believe more in magic than in physics. and such a simple case as

parallel connection chemical current sources causes confusion and vacillation in the minds. so, fortunately, the most commonly used and reasonable method of connecting batteries in parallel, namely identical ones, from the same manufacturer and from the same

rated capacity , almost no one doubts - the total capacity is equal to the capacity of one battery multiplied by their number. Fine. but from time to time questions arise like “but if you connect a good, charged battery with a bad, discharged one that was found in the trash,” then the total capacity will be equal to the capacity of the battery itself large battery, the smallest, average arithmetic capacity, and generally unknown to what, because

good battery

will spend part of its energy on charging the bad, and in general strange processes will occur there, one will discharge before the other, and so on and so forth...

containers always stack when connected in parallel. neither average, nor minimum or maximum, but simply the sum.

a good battery will not recharge a bad one, because for the appearance charging current you need a potential difference between the batteries, and with a parallel connection it is zero.

Always. and therefore, during discharge, the current output from each battery is automatically redistributed in such a way that, as a result, they are discharged simultaneously, regardless of their discharge characteristics and initial capacity.

Let's move on to practical exercises.

We take 2 batteries - Panasonoc CGR18650E and, as far as I remember, Ultrafire 18650 (the cover with the markings has not been preserved) of the DOA category.

pre-charge and discharge each with a current of 0.5A to a voltage of 2.8V

The capacities turned out to be 2403 and 171 mAh, respectively.

internal resistances 85 and 400 mOhm.

we connect them in a parallel assembly, charge and discharge with a current of 1A (that is, formally the same 0.5A for each, if these were the same batteries) to the same voltage of 2.8V.

The capacity provided by such an assembly turned out to be 2661 mAh, which is 87 mAh more than the total capacity of the individual batteries. marvelous? not at all. because the discharge does not occur with the total current divided by the number of batteries, but with a different current, depending on the internal resistance and capacity of each battery. It is clear that a bad battery is discharged with a much lower current than a good one, and therefore delivers slightly more mAh. but in general it is clearly seen that the capacity of the good is not wasted on recharging the bad.

Further. The burning question is what will happen if we stuff various batteries into an expensive flashlight for more than 200 bucks, among which there must be at least one that is completely discharged and has miraculously avoided being sent to the trash can.

nothing will happen:

and this current rapidly drops, after 5-8 seconds it is already a little more than 600mA

Let me remind you that the current strength depends on the circuit resistance and the potential difference, which in turn is determined by the difference in the emf of the batteries and the voltage drop across their internal resistances. that is, the greater the current, the greater the voltage on the discharged side and the less on the charged one, which reduces the potential difference and causes a decrease in the current in the circuit. and this process develops further in the direction of decreasing the current down to 0.

the second option is a parallel connection of charged and discharged, but high-quality, living batteries (less interesting, for some reason most people care about the first option, with a bad battery, and all good ones are going to be used exclusively equally charged)

the current is significantly higher. but it is also gradually falling.

in any case, individual battery protection would simply not work in either case, the current is insufficient. and with protection boards it will be even less, because This is additional resistance.

even if you turn on 3 charged ones and 1 discharged one, most likely the current will not be much higher, because a higher current will cause an increase in the voltage on the discharged battery, which will lead to a decrease in the potential difference, etc.

And finally, I’ll touch on the questions that sometimes come up about what will happen when charging and discharging a parallel assembly of batteries with individual protections. supposedly, when charging, one of the batteries will be recharged before the protection is triggered, will turn off, and more current will flow to the others.

no, just one battery cannot be recharged. In the assembly, the voltage is the same for all batteries, they will all charge at the same time.

just like during a discharge, one cannot switch off due to overdischarge, thereby causing an increased load on the others. can not. because again the voltage is the same on each. parallel connection for.

The battery is a common power source for various mobile devices, gadgets, robots... Without it, class portable devices, probably would not exist or would not be recognizable. One of the most modern types of batteries can rightfully be considered lithium-ion and lithium-polymer. But the device worked, the battery was drained, now you need to take advantage of its main difference from simple batteries– charge.

The article will briefly talk about two common microcircuits (more precisely, about one common LTC4054 and its similar replacement STC4054) for charging single-can Li-ion batteries.

These microcircuits are identical, the only difference is in the manufacturer and price. Another huge plus is the small amount of strapping - only 2 passive component: input 1 µF capacitor and current-setting resistor. If desired, you can add an LED - an indicator of the charging process status; on - charging is in progress; off - charging is complete. Supply voltage 4.25-6.5 V, i.e. Charging is powered by the usual 5V, it’s not for nothing that most of them are built on the basis of these microcircuits simple exercises powered by USB. Charges up to 4.2V. Maximum current 800mA.

The board is based on an LTC4054 or STC4054 charging chip. Input capacitor with a capacity of 1 μF of standard size 0805. Current-setting resistor 0805, resistance is calculated below. And LED 0604 or 0805 with a current-limiting resistor of size 0805 at 680 Ohm.

The resistor (or charge current) is calculated using the following formulas:

Because Vprog=~1V, we get the following simplified formulas

Some calculation examples:

Finally, a couple of photos of the homemade version USB charging for lithium polymer batteries small helicopter.

Lithium batteries are becoming more and more popular, but along with many advantages they have a very significant drawback - the inability to charge without a special controller.
If you charge a lithium battery directly, it will overheat and may catch fire and/or explode!
Of course, you can buy a ready-made controller for a lithium battery, but if you are good with electronics, why not make it yourself?
The easiest way to assemble a controller for charging lithium batteries is specialized chip. One of the most popular charge controller chips is LTC4054.

In its simplest form, the LTC4054 charger looks like this:

The charging current in the LTC4054 is set by a resistor connected to the PROG pin - the lower the resistance of this resistor, the greater the charging current the chip produces! The resistor is selected experimentally, usually its value is about 3.3 kOhm.
The printed circuit board for LTC4054 is several times smaller in size than a matchbox and we can say that this is actually the smallest controller for charging a lithium battery. In addition, it is very easy to manufacture for those who know how to solder SMD parts.

However, it should be noted that this is just a charge controller - it does not protect against overdischarge, therefore, the battery must have a protection board!

If you do not want to purchase it separately, it is better to buy a universal battery controller with built-in protection (see photo below)!

This is the easiest way to replace batteries with a lithium battery! It is enough to solder four wires - two to the battery “can” and two to the device (of course, if the supply voltage is suitable).

Please note that in this controller the charge indicator is made on two LEDs:
- continuous red light indicates that charging is in progress!
- blue that it is completed!
If the blue light is on and the red flickers, the battery is most likely not connected or faulty!!!

Specialized microcircuits TC4054, STC4054, LTC4054 (power controllers) are identical and differ only in manufacturer and price. Their big advantage is the small amount of strapping - only 2 passive elements. If desired, you can turn on the LED with limiting resistor, which will indicate the charging process: lights up during charging and goes out when it’s finished.

The supply voltage of the microcircuit is in the range of 4.25 - 6.5 volts, so the charger on this microcircuit can be powered from USB connectors (by the way, most simple USB-powered chargers are based on these microcircuits). Charges up to 4.2 Vs maximum current up to 800 mA. Has short circuit protection. at the outlet and from overheating.

Such microcircuits can be found, for example, on the boards of phones from Samsung (models X100, C100, C110, E700, E800, E820, P100, P510 and some others). The microcircuit is produced in a small package, but soldering it is relatively convenient. The marking on the case may be “LTH7” or “LTADY”.

Microcircuit pinout:

Charger circuit for TC4054

Here is a circuit diagram of a memory based on this microcircuit. The charge current is set by resistor R2 according to the formula I = 1000 / R2, Where I- current in amperes, R2- resistance in ohms.

It should be noted that at high charging currents, the microcircuit heats up quite noticeably and the optimal charge current for it will be 300 mA (with a resistance of R2 = 3 kOhm). When the microcircuit overheats, the built-in protection circuit automatically reduces the current in the load!

The microcircuit body is not intended for installation on a radiator, so the manufacturer recommends leaving a large amount of copper on the printed circuit board around it (especially on the common ground and on the 3rd pin) and making the widest possible traces on the printed circuit board.

Some sources contained subjective information that microcircuits in the LTH7 package, unlike LTADY, ​​can “raise” a very low battery even with a voltage of less than 2.9 volts, but I personally did not have the opportunity to verify this information.

Analogs TC4054

This microcircuit has many analogues (according to reference literature):

MCP73831, TB4054, QX4054, TP4054, SGM4054, ACE4054, LP4054, U4054, BL4054, WPM4054, IT4504, Y1880, PT6102, PT6181, VS6102, HX6001, LC6000, , CX9058, EC49016, CYT5026, Q7051...

Naturally, before using analogues, it is recommended to check their datasheets ().

Progress is moving forward, and lithium batteries are increasingly replacing the traditionally used NiCd (nickel-cadmium) and NiMh (nickel-metal hydride) batteries.
With a comparable weight of one element, lithium has a higher capacity, in addition, the element voltage is three times higher - 3.6 V per element, instead of 1.2 V.
The cost of lithium batteries has begun to approach that of conventional alkaline batteries, their weight and size are much smaller, and besides, they can and should be charged. The manufacturer says they can withstand 300-600 cycles.
There are different sizes and choosing the right one is not difficult.
The self-discharge is so low that they sit for years and remain charged, i.e. The device remains operational when needed.

"C" stands for Capacity

You can make a simple or not very simple charger yourself, depending on your experience and capabilities.

Circuit diagram of a simple LM317 charger

Rice. 5.

The required charging current for a particular lithium-ion (Li-Ion) and lithium-polymer (Li-Pol) battery is selected by changing the Rx resistance.
The resistance Rx approximately corresponds to the following ratio: 0.95/Imax.
The value of resistor Rx indicated in the diagram corresponds to a current of 200 mA, this is an approximate value, it also depends on the transistor.

It is necessary to provide a radiator depending on the charging current and input voltage.
The input voltage must be at least 3 volts higher than the battery voltage to normal operation stabilizer, which for one can is? 7-9 V.

Circuit diagram of a simple charger on LTC4054

Rice. 6.

Rice. 7. This small 5-legged chip is labeled "LTH7" or "LTADY"

I won’t go into the smallest details of working with the microcircuit; everything is in the datasheet. I will describe only the most necessary features.
Charge current up to 800 mA.
The optimal supply voltage is from 4.3 to 6 Volts.
Charge indication.
Output short circuit protection.
Overheating protection (reduction of charge current at temperatures above 120°).
Does not charge the battery when its voltage is below 2.9 V.

The charge current is set by a resistor between the fifth terminal of the microcircuit and ground according to the formula

I=1000/R,
where I is the charge current in Amperes, R is the resistor resistance in Ohms.

Lithium battery low indicator

Rice. 8.

The nuance of durability

Operation and Precautions

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

From the practice of many years of use, I can say that the battery capacity changes little, but increases internal resistance and the battery begins to work less time at high current consumption - it seems that the capacity has dropped.
For this reason, I usually install a larger container, as the dimensions of the device allow, and even old cans that are ten years old work quite well.

For not very high currents, old cell phone batteries are suitable.

Where do I use lithium batteries?

I put small batteries in children's toys, watches, etc., where 2-3 “button” cells were installed from the factory. Where exactly 3V is needed, I add one diode in series and it works just right.

I put them in LED flashlights.

Instead of the expensive and low-capacity Krona 9V, I installed 2 cans in the tester and forgot all the problems and extra costs.

In general, I put it wherever I can, instead of batteries.

Where do I buy lithium and related utilities

The Chinese usually lie about the capacity and it is less than what is written.

Honest Sanyo 18650