Is it possible to disassemble the battery using a screwdriver? Making an eternal battery for a screwdriver

home

CCTV

The cost of a new screwdriver is approximately 70% the cost of its battery. Therefore, it is not surprising when, faced with a battery failure, we ask ourselves the question - what next? Should I buy a new battery or screwdriver, or maybe there is an opportunity to repair the screwdriver battery with my own hands and continue working with an already familiar tool?

In this article, which we will roughly divide into three parts, we will look at: the types of batteries that are used in screwdrivers (Part 1), their possible reasons failure (part 2) and available methods repair (part 3).

Screwdriver battery: design and types

It should be noted that regardless of the brand of screwdriver and the country of manufacture, the batteries have an identical structure. The assembled battery pack looks like this.

If we take it apart, we will see that it is assembled from small elements that are assembled sequentially. And from the school physics course we know that elements that are connected in series balance their potentials.

Note. The sum of each battery element gives us the final voltage at the battery contacts.

Set pieces or "cans" usually have standard size and voltage, they differ only in capacitance. Battery capacity is measured in Ah and is indicated on the cell (shown below).

The following types of elements are used to assemble screwdriver batteries:

nickel - cadmium (Ni - Cd) batteries, with a nominal voltage on the “banks” of 1.2V;
nickel-metal hydride (Ni-MH), element voltage - 1.2V;
lithium-ion (Li-Ion), with a voltage of 3.6V.

Let's take a closer look at the advantages and disadvantages of each type.

The most common type due to its low cost;
Low temperatures are not scary, for example, like Li-Ion batteries;
It is stored in a discharged state, while retaining its characteristics.

Produced only in third world countries due to toxicity during production;
Memory effect;
Self-discharge;
Small capacity;
A small number of charge/discharge cycles means they do not “live” for a long time with intensive use.

Environmentally friendly production, it is possible to purchase a high-quality branded battery;
Low memory effect;
Low self-discharge;
Large capacity compared to Ni - Cd;
More charge/discharge cycles.

Price;
Loses some of its characteristics when stored for a long time in a discharged state;
At low temperatures does not “live” for long.

No memory effect;
Almost no self-discharge;
High battery capacity;
The number of charge/discharge cycles is many times greater than that of previous types of batteries;
To set the required voltage, a smaller number of “cans” are needed, which significantly reduces the weight and dimensions of the battery.

High price, almost 3 times compared to nickel-cadmium;
After three years, a significant loss of capacity occurs, because Li decomposes.

We got acquainted with the elements, let's move on to the remaining elements of the screwdriver battery pack. Disassembling the unit, for example to repair the battery Hitachi screwdriver(shown below), is very simple - unscrew the screws around the perimeter and disconnect the case.

The housing has four contacts:

Two power ones, “+” and “-”, for charge/discharge;
The upper control is switched on via a temperature sensor (thermistor). The thermistor is necessary to protect the batteries; it turns off or limits the charging current when a certain temperature of the elements is exceeded (usually in the range of 50 - 600C). Heating occurs due to high currents during forced charging, the so-called “fast” charging;
The so-called “service” contact, which is connected through a 9Kohm resistance. It is used for complex charging stations that equalize the charge across all battery cells. In everyday life, such stations are useless due to their high cost.

That's the whole design of the battery. Below is a video on how to disassemble the block.

Troubleshooting

We have figured out the purpose of the battery design elements, now let’s look at how to determine the malfunction, this is part 2 of repairing a screwdriver battery. Let us immediately note that all elements cannot fail at once, and since our circuit is sequential, if one element fails, the entire circuit does not work. This means that our task is to determine where the weakest link is in our chain.

To do this, we will need a multimeter, and for the second method of troubleshooting, a 12V lamp, if your battery for the screwdriver is also 12 volt. The procedure is as follows:

We put the battery on charge and wait for a signal about full charge.

We disassemble the case and measure on each battery bank. For Ni - Cd we should have 1.2 - 1.4V, for lithium - 3.6/3.8V.

Mark all “banks” in which the voltage is less than the nominal one. For example, most Ni-Cd elements have a voltage of 1.3V, and one or more have a voltage of 1.2/1.1V.

We assemble the battery and work until noticeable loss power.

We remove, disassemble and measure the voltage drop on the battery “banks”. On the marked elements the voltage “sag” will be greater than on others. For example, they are no longer 1.2V, but 1.0V or even lower.

Note. A difference between the elements in a battery of 0.5 - 0.7V is considered significant, which means that the element becomes unusable.

Thus, we found candidates for “reanimation” or “amputation” and replacement with new elements.

If your screwdriver operates on a voltage of 12 or 13V, you can search for more simple method. We disassemble a fully charged battery and connect a 12 volt lamp to the “+” and “-” contacts. The lamp will be a load and will drain the battery. Next, we take measurements on the battery elements, where the voltage drop is greatest, there is a weak link.

There are other ways, instead of a lamp you can select a resistance, but this already requires the basics of electrical engineering, and it is doubtful that a resistor with the necessary resistance would be at hand.

Other malfunctions are very rare. For example, loss of contact in the soldering areas of batteries or power contacts of the unit, failure of the thermistor. This problem is more common with fakes. Due to its rarity, we will not focus on the battery elements.

The “problematic” elements have been dealt with and need to be repaired. How to repair a screwdriver battery? In general, there are 2 methods available for repair, so to speak. This is the restoration and replacement of elements that have become unusable.

Is it possible to “reanimate” elements and how?

Let's proceed to Part 3 of screwdriver battery repair and immediately make a reservation that the concept of “reanimation” for lithium-ion batteries is not applicable. There is no memory effect in them; most likely, lithium decomposition has occurred, and nothing can be done about it. In such batteries, it is necessary to find out what is the cause of the malfunction: the element itself or the control circuit. There are two options here:

we change the control circuit from another, but similar to ours, battery, if it helps, we find a replacement and change it;
supply 4V to the element with a current of approximately 200mA, for this you need a regulated charger. If the voltage on the element increases to 3.6V, the element is working properly, the problem is in other elements, or in the control circuit.

Screwdriver battery repair is available primarily for Ni-Cd batteries, but they are usually the most common in household screwdrivers.

So, how to reanimate a screwdriver battery? There are two types of “reanimation” for these types of batteries:

Compaction or compression method (this will work in cases where the electrolyte is still available, but volume has been lost);
“Firmware” with voltage and current greater than the nominal one. This method allows you to eliminate the memory effect, and although not completely, restore the lost capacity.

This method is shown in the video below.

Note. As a rule, in a nickel-cadmium battery the main reason for loss of capacity is boiling away of the electrolyte, and if it is critically low, no amount of “firmware” will help.

This method, if its result is positive, will not solve the problem of element failure. Rather, it will only delay the replacement of those that have become unusable, and in the future you will still need to repair the battery of a Makita screwdriver or any other.

Repair and replacement of screwdriver battery elements

More effective way repair of batteries for a screwdriver - replacement of elements that we have determined to be faulty.

To carry out repairs, we need either a “donor” battery, in which some of the elements are working, or new “banks”. It won't cost you to buy them a lot of work, even on the Internet you can easily find a dozen stores that are ready to send these items by mail. The price is not particularly bad, for example, a nickel-cadmium cell with a capacity of 2000 mAh costs around 100 rubles.

Note. When purchasing a new element, make sure that its capacity and dimensions match the original elements.

We will also need a soldering iron, low-corrosive flux (preferably alcohol flux with rosin) and tin. We are not talking about spot welding, since for a one-time battery repair there is hardly a need to purchase or assemble it...

There is nothing complicated about the replacement itself, especially if you have at least some experience in soldering. The photographs show everything in sufficient detail; we cut off the faulty element and solder a new one in its place.

Several points need to be noted:

When soldering with a soldering iron, try to solder quickly so that the battery does not heat up, because you risk ruining it;
if possible, make the connection using original plates, or use copper plates of the same size, this is important because the charging currents are large and if the connecting wires are of the wrong cross-section, they will heat up, and accordingly the thermistor protection will be triggered;
Do not under any circumstances confuse the plus of the battery with the minus - the connection is in series, which means that the minus of the previous can goes to the plus of the new can, and the minus of the new one goes to the plus of the next one.

After the new elements have been soldered, it is necessary to equalize the potentials on the “banks”, since they are different. We carry out a charge/discharge cycle: set it to charge overnight, give it a day to cool down and measure the voltage on the elements. If we did everything correctly, the picture will be something like this: all elements have the same multimeter reading, within 1.3V.

Next, we proceed to discharge the battery, insert the battery into the screwdriver and load it “to its fullest.” The main thing is to spare the screwdriver itself, otherwise you will have to repair it too. We bring it to full discharge. We repeat this procedure two more times, i.e. charge and completely discharge.

It should be noted that the procedure for erasing the “memory effect” should be carried out once every three months. It is carried out in a similar way to the training described above.

This not-so-tricky procedure will prolong the operation of your screwdriver, at least until it has to be replaced with a new one.

When using a screwdriver for a long time or storing it, after a certain time, the battery of the screwdriver becomes unusable. Further use of the tool becomes impossible. The consumer has to consider the option of purchasing a new battery or screwdriver. This decision problem is the simplest way out of this situation, compared to replacing the batteries in the old battery.

The cost of a new battery is about 60% of the cost of a screwdriver. Each battery contains the same type of cells, which are also sold separately. You can try to repair the battery. Repairing it is not considered a very difficult process, but in case of an unsuccessful attempt, the user can purchase new battery. Below in the article we will discuss in detail the issues of repairing a screwdriver battery with your own hands.

Types of batteries

Today there are screwdrivers on sale with the following types of batteries: nickel-cadmium; nickel metal hydride; lithium-ion.

Each type has its own advantages and disadvantages. Let's take a detailed look at each type.

There are 3 types of screwdriver batteries:

Nickel-cadmium (Ni-CD).
Nickel metal hydride (Ni-Mh).
Lithium-ion (Li-ion).

There are several solutions to restore each of them.

Memory effect occurs when the battery is not sufficiently discharged and then recharged. Over time, the battery “remembers” its lowest discharge limit and uses less and less battery capacity. The problem is more relevant for Ni-Cd batteries, and to a lesser extent for Ni-Mh. Lithium-ion batteries do not have a memory effect.

To solve the problem, you need to completely discharge and charge the battery several times. This can be done using a 12 volt light bulb. You can take a light bulb with a slightly higher or lower voltage. Two wires are soldered to the light bulb, positive and negative, which are respectively attached to the battery contacts. The procedure must be repeated at least 5 times.

Adding distilled water to nickel-cadmium batteries

One of the most common problems with Ni-Cd batteries is evaporation of distilled water. Most often occurs when the battery overheats. To solve the problem you need to:

Disassemble the battery.
There will be small batteries inside (about 14 pieces, depending on the screwdriver model). Using a multimeter you need to find the failed part. The voltage on the working “barrel” will be in the range from 1 to 1.3 volts. Anything below this mark requires repair.
Faulty items are carefully removed. The plates that attach them to other batteries will be useful for assembly later.
On the side, closer to the top or bottom of the battery, there is a bend where you need to make a hole with a diameter of no more than 1 mm. You only need to drill the wall, without going deep inside.
Now you will need a syringe with a needle and distilled water (in no case plain water from the tap). The syringe is inserted into the hole made, and the battery is filled to the brim. It is advisable for it to remain in this state for a day.
Device for charging nickel cadmium batteries(IMAX is suitable), charging is carried out, after which the battery must be allowed to sit for another week.
After 7 days, check to see if the voltage has dropped. If all is well, you need to seal the holes using silicone or a soldering iron.
Next, the batteries are assembled in reverse order and placed in the battery case. For soldering, spot welding or a regular soldering iron is used.
After checking the functionality, the battery is completely discharged under light loads and charged again at least three times.

Replacing batteries

Disassemble the battery.
Use a multimeter to find faulty elements. On nickel-cadmium and nickel-metal hydride batteries, the voltage should be around 1.2 volts, on lithium-ion batteries – around 3.6 volts.
Faulty elements are carefully removed and exactly the same batteries must be purchased in their place.
New elements are put in place of old ones. Old plates are used for connection.
Soldering is done with a soldering iron or spot welding. You need to work with a soldering iron very carefully and quickly so as not to overheat the battery. It is advisable to use flux, or, in extreme cases, rosin.

Release of gas from lithium-ion batteries

IN lithium-ion battery There are several separate batteries. During operation, one or more of them may overheat, which will lead to evaporation of the electrolyte. Thus, a large amount of gas will accumulate inside the battery and it will swell, bending the thermal plate. To solve the problem you need to:

Disassemble the battery.
Use a multimeter to find the dead battery. Its voltage will be 0.
Next, you need to remove it from the chain and release the gas. This can be done in two ways:

Take scissors with a curved end or any other similar tool, place them under the positive contact and gently press the swollen plate down. In this case, the gas will make a hole somewhere to find its way out. In fact, this method Only restores battery functionality for a short time. Subsequently, through the hole made by the gas, all the electrolyte will evaporate, without which the battery will not work.
Take small wire cutters and disconnect the positive contact so that it can be bent (no need to cut off completely). Next, you need to use an awl with a blunt end, which is inserted under one of the edges of the curved plate and gradually push it inward (disconnect the plate and the edge of the battery). When the gas comes out (it will be audible), the swollen plate must be pressed into place, and the hole made must be soldered with a soldering iron or covered with silicone. And also solder the contact that was disconnected at first.

Now you need to charge the battery using the IMAX device.

Battery excitation

The method is suitable for all types of batteries. Necessary:

Disassemble the battery.
Use a multimeter to find dead batteries.
Excite them using a pulse discharge. Suitable for this: 12 volt battery, power supply, spot welding, etc. The impulse should be short-lived and should not be repeated many times. It is enough to excite the battery so that the charger can see it.
Reassemble all the cells (if they were disassembled) and place them in the battery case.

This method is imperfect, since after some time (from a week to a month) the voltage of the batteries will drop again. This is especially true for nickel-cadmium batteries.

Hello! Today we will repair the screwdriver battery. Do you know that the history of the creation of a screwdriver goes back to the deep Middle Ages - all the way back to the 15th century, when knights put on armor before battle, and squires helped them twist parts of the armor with guess what? With a screwdriver!

This went on for a long time, until in 1907 the Canadian inventor Peter Robertson patented the Robertson screw with a standard square hole, into which the tip of a screwdriver was inserted. From that time on, screws began to be produced in industrial scale and apply in household. Later, in 1934, inventor Henry Phillips modified the screw head and a screw with a Phillips notch appeared, into which a corresponding screwdriver was inserted. By that time, the engine had already been invented and the idea of creating a “rotator of screws and screws” was in the air. However there were big problems with batteries - their weight and dimensions. The problem was solved only in the 1980s, when the first nickel-cadmium Ni-Cd and lithium-ion Li-Ion batteries appeared.

The USA and Japan were the first to master the production of household and professional products. All this happened thanks to the advent of new energy-intensive electricity batteries. We will urgently change them inside the Interskol DA-10/10.8 ER cordless drill-driver that fell into my hands. The problem was this: When you press the button, the engine simply does not turn, but the LED lights up, though the light was weak.

Disassembling the screwdriver battery

Let's start repairing the screwdriver battery. We extract battery from the screwdriver handle and unscrew the three screws that are located under the sticker at the bottom.

After unscrewing the screws, carefully move the hooks of the latches, as in the photo. And we film bottom part plastic battery case.

Inside we see lithium-ion banks Chinese company HighStar model ISR18650-1300 Li-Ion. This means that the batteries have never been changed. Because it is known that Interskol purchases batteries from this company and inserts them into almost all of its products.

The photo below shows the insides of the screwdriver battery in all its glory with three cans, which were produced back in 2011. These lasted five years with active use at a construction site. So the result is very worthy. They usually die earlier, probably they were not used in cold weather.

To replace the battery banks you need to disassemble it further. I advise you to remember the location of the plus, minus and charging contacts so as not to confuse the wires when reassembly.

Pay attention to the voltage control board on the batteries - especially often they fail. It is imperative to ring suspicious radio elements on this board.

We check the voltage at the battery output - it turned out to be 4.4 volts, but it should be 3.7 x 3 = 11.1 volts normally and 10.8 volts with minimal charging. In general, the banks are dead - they definitely need to be changed.

We continue to disassemble the Interskol screwdriver battery

This can be done in several ways - you can unsolder the wires that go to the board.

You can also simply remove the contacts from the top battery cover. The photo shows what shape the curved contacts have, so you can easily remove them yourself.

Under plastic cover We see how the batteries are connected to each other. Their spot welded. This solution is used in almost any battery of another tool. This is a reliable and gentle battery connection. At the same time, the destructive heating of the lithium batteries themselves is minimal.

Carefully tear off or bite off the metal tape with pliers to disconnect the cans from each other. On the board side, they were also connected to each other with tape and placed on a cardboard spacer with glue. This is done so as not to short anything on the board. You must remember to return it to its place when reassembling the battery.

New lithium-ion batteries due to the lack of a device for spot welding We will solder with a well-heated, powerful soldering iron very quickly. We remember that heating reduces their service life and is generally explosive.

Pay special attention to the condition of the wires inside the battery. They may be broken or frayed. They need to be properly insulated or replaced with fresh ones. Since I was repairing the screwdriver battery on the road in field conditions, then I had to use a brilliant invention of an engineering mind. I took out blue electrical tape.

Solder the batteries

It can be done in different ways, for example with thick wires. I decided to solder some torn metal strip taken from old cans. First, I tinned the tapes in the places of future contacts on both sides. After Using a well-heated soldering iron with a drop of solder, I tinned the battery contacts. But so that they do not heat up too much - let them cool. Then I pressed the tape to the contacts of the cans and soldered the tape, again without severe overheating.

The most difficult thing to solder is the negative terminals, but it goes very quickly. True, it is better to wash the flux later to clean the insides of the battery.

Now the most important thing. What batteries were used when repairing the battery of the Interskol DA-10/10.8 ER screwdriver, you ask? Well, I won’t hide it. These were the most Chinese of the cheap cans that the owner of the device honestly bought in the store. from Bailong with a fictitious capacity of 8800 mAh. This is of course a laugh and God forbid they have 2200 mAh. Judging by how long the screwdriver worked after the repair on a full charge. I would reduce this figure by half. But nevertheless, the screwdriver was urgently repaired and it makes the owner happy.

A dead screwdriver battery can be recharged. But if discharge occurs more often and the power decreases, these are signs of battery failure. Usually, owners immediately try to replace the damaged unit with a new one. But after comparing the cost of a separate battery for a Bosch screwdriver with the price of a new tool with two batteries, they often choose a new set.

Battery composition and parameters

The situation is not as sad as it seems at first glance. Sometimes it is possible to repair a screwdriver battery with your own hands without financial costs or at low cost. To know how to repair a battery pack at home, you should get a voltmeter, a soldering kit, a screwdriver, a penknife, and familiarize yourself with the types and properties of elements used in batteries.

The operating principles of electrical energy storage elements are the same for both capacitors and batteries. A thin layer of dielectric, the electrolyte in the case of batteries, separates two layers of metal foil on which charges of opposite polarities accumulate. When electricity consumers are connected between the contacts of the layers, the flow of charges moves through it to the opposite layer, doing work. Thus, the main characteristic of a battery is the amount of accumulated charge, expressed in ampere-hours. The generally accepted abbreviation A/h or A/h is printed on any battery.

The charge between the plates generates static electrical voltage. If, during charging, the rated voltage for which the battery is designed is allowed to be significantly exceeded, the electrolyte layer will be pierced, which will disable this element completely. Reduced charger voltage will reduce the power stored in it. The second parameter of the battery is voltage. One element, depending on the type, maintains voltage ranging from tenths to several units of volts.

Characteristics of their types

The difference is chemical composition plates and electrolyte, dimensions, and the relative position of components determine not only the performance characteristics of batteries, but also the cost. As always: the better, the more expensive. For screwdrivers, the optimal price-quality ratio is inherent in three types metal plates. Two are based on nickel with the addition of cadmium (Ni-Cd) or metal hydride (Ni-Mh), one type uses lithium and is designated Li-Ion (lithium-ion batteries). Each type has its own characteristics and characteristic malfunctions.

Nickel-cadmium type has low price, frost tolerance, long-term discharged storage. Low voltage 1.2 V on each bank increases their number in the battery. Negative characteristics include a small number of discharge-charge cycles, high self-discharge, memory of a low charge level, environmentally harmful production and composition.

Nickel-metal hydride batteries are more expensive, but their self-discharge is lower, they can withstand more charge-discharge cycles, their low-charge memory is not as strong, and they are environmentally friendly. The charge of the jar is 1.25 V. In terms of frost resistance, it is more gentle than cadmium and the shelf life is shorter.

Lithium-ion devices are more expensive than nickel-metal hydride devices. Have high voltage elements 3.6 V. Advantages of the technology - there is no self-discharge and low-charge memory, the capacity is higher than that of other types, greatest number charging cycles. Cons - the shelf life is the shortest, the elements are environmentally harmful when disposed of.

Screwdriver battery design

The plastic case hermetically seals the contents of the battery with the exception of sockets, metal terminals or contact pins intended for operating charge-discharge currents and, if there are more than two contacts, for charge control.

Since the battery is not functioning, repairing the screwdriver battery requires disassembly and opening the plastic case. If there are screws, they must be unscrewed. In the sealed case, you should deeply scratch the glue line with a knife and cut or carefully drill a shallow hole in it. Then, by screwing in a conical screw, you need to make a gap appear and, using a knife or screwdriver, expand it to the full perimeter of the gluing. During assembly after repair epoxy resin will seal the gap no worse than before.

The screwdriver battery structure is visible when opening the case:

several batteries connected in series;
a temperature sensor attached to one of the elements with a charging current interrupter when the battery heats up;
control board, but only in lithium batteries.

However, it is worth starting diagnostics before opening the case.

Troubleshooting

For diagnostics, you will need a tester or a constant voltage voltmeter, a charger and a little time. It is better to start your search by measuring the battery voltage before and after full charging. The voltage value of the charged elements must be compared with that indicated on the case and measured before charging. Options for voltage measurement results will tell you how to fix a screwdriver battery:

It was and remains zero.
Equal to or greater than nominal.
Remained at the same level as before charging.
Rapid decrease in voltage without load and stabilization below the nominal value indicated on the case.

Now the faulty element for repair is purposefully identified.

Repair of batteries for screwdrivers

You can restore the screwdriver battery design feature- serial connection of identical elements. This scheme prevents simultaneous failure of all battery cells. This means you will need to find one or more faulty elements.

Old batteries lose capacity when the electrolyte dries out. IN critical situation, when it is impossible to replace the can, hope for temporary restoration will be given by heating the can to 60–70 degrees or lightly compressing the body with pliers.

A battery with a restored or replaced battery will not be superfluous, and from two identical faulty batteries, thanks to the interchangeability of the elements, you can assemble one working one and hold off on purchasing a new tool.

Sections