Nickel cadmium batteries how to charge and store. From the history of creation

12.06.2019

Even though nickel cadmium batteries since this year banned from production in the EU countries, these tireless workers are still used in many inexpensive and powerful autonomous devices (screwdrivers, electric shavers, flashlights).

Even if the instruction manual does not say anything about the type of battery of the device, it is quite simple to determine that it is the nickel-cadmium battery that serves as a current source - most often the charging time is indicated in the range of 5-12 hours and there is an indication of the need to turn off the charger on its own after charge time.

For nickel- cadmium batteries Fast pulse charging is preferable to slow DC charging. These batteries can deliver a lot of power, making them the choice for high power standalone applications. Nickel-cadmium batteries are the only type of batteries that can withstand full discharge under heavy load without any consequences. Other types of batteries require incomplete discharge at relatively low power loads.

Nickel-cadmium batteries do not like long-term charging with occasional light loads. Periodic full discharge is necessary for them like air is for a person - in the absence of a complete discharge, large metal crystals form on the electrodes (which leads to the manifestation of the so-called "memory effect") - the battery abruptly loses its capacity. For long and effective work NiCd batteries require battery maintenance cycles - a complete discharge followed by a full charge, based on most recommendations - once a month, at least once every 2-3 months.

Nickel-cadmium batteries are the most "fool-resistant" of modern mass batteries - they do not even require a system for monitoring battery parameters, which determines their use in inexpensive and powerful devices.

Charging with low currents in 5-12 hours allows you to do without any precautions in the form of charge-discharge control systems. When recharging, the battery will simply slowly lose capacity (to the delight of the manufacturer). Be aware of this when using "bad-boy" chargers (chargers without mechanism automatic control charge). Therefore, it is best to charge a completely discharged battery and strictly observe the charging time, which will save NiCd capacity battery for quite a long time.

When using “fast” charging (with a charge time of less than 5 hours), it is desirable to have a charger with a temperature sensor, since the temperature of the battery rises during charging, the capacity increases along with the temperature, as the capacity increases, the charger can recharge the battery above the required level, which leads to an even greater increase in temperature (the phenomenon of "thermal acceleration" of the battery) and, at a minimum, to a deterioration in battery parameters. A similar situation exists when charging the battery at low temperatures. Temperature sensor allows you to shift the charge parameters depending on the battery temperature, as well as disconnect the battery from charging when the temperature rise rate exceeds 1 degree Celsius per minute or when the battery temperature reaches 60 degrees Celsius, which avoids the tragic consequences of thermal runaway.

As an illustration of the need for a temperature sensor in a charger, I can give an example of a two-year-old charge of a nickel-cadmium battery for a professional screwdriver on a charger without a temperature sensor (in the photo - this is the charger itself), which allows you to charge the battery at an accelerated pace - in an hour. At that time, the temperature in the apartment was about 30 ° C, the charger should automatically charge the battery until the target voltage is reached and automatically turn off, which was said in English in white in the instructions in the safety section. In the morning, the first battery from the set was charged without any excesses - after 50 minutes the charger turned off, towards the evening the second battery gave a surprise when charging: due to the lack of a temperature sensor in the charger, the battery entered the thermal acceleration mode. Since the charge was accelerated, the problem was noticed late - when the battery went into smoke and began to spray hot electrolyte. The charger, which was quickly disconnected from the network, was saved. The battery snorted in agony for a long time, trying to cause as much damage as possible when leaving for another world, but it failed and the damage was limited to the cost of the battery itself - 15USD. Since then, the charger has been connected to the network through a timer.

Despite their shortcomings, nickel-cadmium batteries still exist among us. I hope that some of the theory and practical experience presented in the article will allow the reader to get the most out of the nickel-cadmium battery of his device that he is capable of.

Nickel-cadmium batteries (Ni-Cd) on this moment are still widely used in the national economy. According to their structure, they belong to the group alkaline batteries. These batteries are in demand, despite the fact that their production and use is limited for security reasons. environment(cadmium is toxic). But it is impossible to completely abandon them, since these batteries are used in devices where other batteries cannot work. In particular, this is operation with discharge and charging currents large size. These are fairly easy to maintain devices with a long service life. Therefore, they deserve consideration in a separate article.

The first nickel-cadmium battery was created by Waldmar Jungner back in 1899. But then the production of these alkaline batteries was much more expensive than other types of batteries. So, this invention was forgotten for a while. In 1932, a method was developed for depositing an active material onto a porous nickel electrode. This brought the release of industrial Ni-Cd batteries closer.

In 1947, a number of works were carried out, during which the gases released during the charge were recombined without their removal. As a result, sealed Ni-Cd batteries were born, which are still used today. Manufacturers of nickel-cadmium batteries include: large companies like GP Batteries, Samsung, Warta, GAZ, Konnoc, Advanced Battery Factory, Panasonic, Metabo, Ansmann and others.

Despite being widely used in the national economy over the past decades, nickel-cadmium batteries are gradually narrowing their scope. They are gradually being replaced by nickel-metal hydride and lithium batteries.

In particular, Ni-Cd batteries are giving way to portable technology. The reason for this is the danger of cadmium to humans and the environment. Disposal of these batteries requires special equipment to capture cadmium. for the car is carried out easier, faster and better worked out. But there are still quite a few areas where nickel-cadmium batteries are indispensable.

The use of nickel-cadmium batteries (Ni-Cd)

Nickel-cadmium batteries with small dimensions are used in technical devices that require a large current for their operation. In such conditions, Ni-Cd batteries provide stable power and do not overheat, unlike other types. batteries. Nickel-cadmium batteries are widely used in trolleybuses, trams, as traction batteries on electric cars, industrial Ni-Cd batteries are found. In addition, they are widely used in sea and river transport.

Ni-Cd batteries can be found in helicopters and airplanes as on-board batteries, in portable tools (screwdriver, puncher, etc.). However, lithium batteries are increasingly found in tools. Nickel-cadmium batteries cannot yet be replaced in those portable devices that have high power consumption. Although in some devices they are successfully replaced, which do not contain harmful cadmium.

Disc-shaped Ni-Cd batteries have found wide application. This variant was widely used as a battery to power non-volatile memory in early personal computers. They were soldered on the motherboard. They were subsequently replaced lithium batteries. Disc batteries were also widely used in cameras, flashes, calculators, flashlights, radios, hearing aids, etc.

Ni-Cd batteries can be stored for a long time, are easy to maintain, are insensitive to low temperatures, have low internal resistance and low specific gravity. All this outweighs negative moment associated with the presence of toxic cadmium in them. Nickel-cadmium batteries continue to dominate their use in aviation, military equipment, and mobile radios. Additionally, you can read the material on how Ni-Cd is reduced.

Device nickel-cadmium batteries (Ni-Cd)

Construction of Ni-Cd batteries

Structurally, a nickel-cadmium battery is a positive and negative electrode separated by a separator. They are immersed in an alkaline electrolyte and all this is closed in a sealed metal case. The positive electrode contains NiOOH (nickel oxide-hydroxide). The composition of the negative contains cadmium (Cd) in the compound. The electrolyte is KOH (potassium hydroxide). It is a strong alkali, odorless. The advantages of KOH are that the substance is neither explosive nor flammable. The mass fraction of KOH in the electrolyte according to GOST R 50711-94 should be at least 85 percent in solid form and at least 45 percent in liquid form.

To increase the surface area of the electrodes, they are produced from a thin foil. The separator between the electrodes is made of non-woven material that does not interact with alkali. The electrolyte itself is not consumed during the reaction.

One nickel cadmium element produces a voltage of about 1 volt. Therefore, they are combined into batteries with an energy density of approximately 60 Wh per kilogram.

In the image below, you can see the main elements of the alkaline nickel-cadmium battery of the KL series.

Born or current output is designed to remove current from the battery and acts as a terminal for connecting batteries. Through the plug, the electrolyte is filled, as well as the exit of the gas formed during the charging process. The connection of the electrodes together with the contact strips ensures the removal and supply from the electrodes to the burner. The contact strips are welded to the electrodes.

The electrode is a lamella arranged horizontally. They contain the active substance in a perforated steel band. The rib gives the rigidity of the electrode and ensures the flow of current to the contact strip. Electrodes of different polarity are separated by a frame separator, which does not interfere with the free circulation of the electrolyte.

Reactions taking place on the electrodes of the Ni-Cd battery

Processes on the positive electrode

The main electrochemical reactions occurring at the positive electrode of a nickel-cadmium battery can be described by the following formulas:

In the process of charging

Ni(OH) 2 + OH - ? NiOOH + H 2 O + e -

During discharge

NiOOH + H2O + e - ? Ni(OH) 2 + OH -

Nickel oxide-hydroxide (NiOOH) on the positive electrode can be in two versions:

?- Ni (OH) 2;
?-Ni(OH) 2 .

These forms differ in their density and hydration. If the battery is dead, then both of these forms of nickel hydroxide are present on the positive electrode. When a Ni-Cd battery is charged, the ?-Ni(OH) 2 form becomes ?-NiOOH. In this case, the crystal lattice of the substance changes somewhat. At the final stage of charging, β-NiOOH is formed. Number of phases? And? Nickel hydroxide will depend on the specific charge conditions.

Phase? intensively formed at high speed charging or overcharging. As a result of the formation of α-NiOOH, a radical rearrangement of the structure of oxides occurs. For comparison, phase density? is 4.15, and the phase? -3.85 g / cm 3. For this reason, when the Ni-Cd battery is recharged, the volume of the active mass of the positive electrode changes. Electrochemical properties? And? are also different. For the ?-NiOOH form, the charge passes less efficiently and the current utilization factor in this case is less than the ? form. Form? also has a lower discharge potential and self-discharge two times smaller than for?.

Processes on the negative electrode

The following reactions take place at the negative electrode of a nickel-cadmium battery:

When charging

Cd(OH) 2 + 2e? ? Cd+2OH?

When discharging

Cd+2OH? ? Cd(OH) 2 + 2e?

The capacity of the cadmium electrode in nickel-cadmium batteries exceeds the capacity of the positive electrode by about 20-70 percent. For this reason, it is believed that the potential negative electrode during charge-discharge, remains unchanged.

General processes in a Ni-Cd battery

IN nickel cadmium battery the following reactions take place:

When charging

2Ni(OH) 2 + Cd(OH) 2? 2NiOOH + Cd + 2H2O

When discharging

2NiOOH + Cd + 2H2O? 2Ni(OH) 2 + Cd(OH) 2

In the process of overcharging, the following reaction occurs at the positive electrode:

2OH? ? 1/2O2 + H2O + 2e?

That is, oxygen is released, which reaches the negative electrode through the separator, and there, with its participation, the following reaction takes place:

1/2O2 + Cd + H2O? Cd(OH)2

The result is a closed reaction on oxygen. This stabilizes the pressure in the nickel-cadmium battery when overcharging. The amount of pressure in the battery is largely dependent on the rate of oxygen transport between the positive and negative electrodes. In the process of recharging, hydrogen can be released at the negative cadmium electrode:

H2O+e? ? Oh? + 1/2H2

It then oxidizes at the positive electrode. The reaction looks like this:

NiOOH + 1/2H2? Ni(OH)2

Hydrogen formation in sealed battery is a dangerous process. If the rate of its absorption is low, then this can lead to its accumulation. And it's already explosive. Therefore, in sealed nickel-cadmium batteries, the capacity of the cadmium electrode is made much larger than the positive one.

The capacity of such a sealed battery is determined precisely by the value of the capacity of the nickel oxide electrode.

Characteristics of nickel-cadmium batteries (Ni-Cd)

The nominal voltage of nickel-cadmium sealed batteries is 1.2 volts. A charge with a current of 1/10 of the capacity occurs in 16 hours. The capacity of a Ni-Cd battery is measured when it is discharged with a current of 2/10 from rated capacity to a voltage of one volt.

In the image below, you can see the discharge characteristics of nickel-cadmium batteries in various discharge modes.

In the graphs below, you can see the dependence of the discharge capacity on the load current and temperature.

The self-discharge of nickel-cadmium batteries depends mainly on the thermodynamic instability of the nickel oxide-hydroxide electrode. The influence of the leakage current between the electrodes on self-discharge is small. But it gradually increases with battery life. Heat dissipation in Ni-Cd batteries largely depends on the degree of charge. After the battery has gained 70 percent capacity, the process of oxygen evolution is activated. As a result, due to the ionization of oxygen at the negative electrodes, the battery is heated. At the end of charging, the temperature in the Ni-Cd battery rises by 10-15 degrees Celsius. If the charge is carried out in an accelerated mode, then the temperature increase can be 40-45 degrees Celsius.

After disconnection from the charge, the potential of the positive (nickel oxide) electrode decreases and the charge of the deep and surface layers is gradually equalized. After a while, the intensity of self-discharge decreases. For different series of Ni-Cd batteries, self-discharge and stabilization of residual capacity can vary significantly. Self-discharge, in addition to reducing the capacity, also leads to a decrease in voltage by 0.03-0.05 volts. This phenomenon is explained by the gradual equalization of the charge in the depth and on the surface of the electrode. In addition, partial passivation of the active mass has an effect.

Storing nickel-cadmium batteries (as well as lead-acid batteries) at a low temperature reduces self-discharge. At 20 degrees Celsius, the self-discharge is twice that at 0.

The following image shows a graph of capacity loss for NiCd batteries at various temperatures.

To compensate for self-discharge during storage of the battery, you can put it on a low-current charge. Typically, the charge current value is 0.03-0.05 of the capacity. But the specific value is negotiated by the battery manufacturer. The ability to withstand a long recharge is different for nickel-cadmium batteries of various designs. Disk alkaline nickel-cadmium batteries, which have lamellar electrodes of large thickness, are the least suitable for recharging. But there are also such designs that are able to withstand recharging for several months without consequences.

As for the energy characteristics of Ni-Cd batteries, they also differ depending on the battery types.

Disc nickel-cadmium batteries with 2 electrodes have specific energy characteristics of 15-18 Wh per kilogram and 35-45 Wh per liter. The same variety, but with 4 electrodes, has twice the specific energy characteristics. For cylindrical Ni-Cd batteries, these values are 45 Wh per kilogram and 130 Wh per liter.

What affects the discharge of Ni-Cd batteries?

The discharge characteristics of specific models depend on the following characteristics:

thickness, structure, internal resistance of electrodes;
assembly density of electrode groups;
separator characteristics (thickness and structure);
electrolyte volume;
specific design features of the battery.

Disk Ni-Cd batteries with thick pressed electrodes are used in long-discharge conditions. In this case, there is a gradual decrease in capacitance and voltage to 1.1 volts. When discharged to 1 volt, the capacity remains about 5-10 percent of the nominal value. Such rechargeable batteries demonstrate a significant reduction in the discharge voltage and lost capacity of Ni-Cd batteries with an increase in the discharge current to a value of 0.2*C. This is explained by the fact that the active mass does not have the ability to uniformly discharge at different depths of the electrodes.

For batteries operating in the medium-intensity discharge mode, electrodes are made thinner, and their number increases to 4. As a result, the discharge current increases to 0.6 of the capacity.

There are also so-called short-discharge batteries. They are equipped with ceramic-metal electrodes with low internal resistance. These models have the highest energy performance among other types of nickel-cadmium batteries. Their voltage during discharge is kept above 1.2 volts until they exhaust 90 percent of the battery capacity. These batteries can be used when discharging with high current values (3-5C).

It is worth noting also cylindrical batteries with rolled electrodes. These modern batteries can be discharged for a long time with a current of 7-10C. On the discharge graphs presented above, it can be seen that the temperature of the OC has a significant impact on the characteristics of nickel-cadmium batteries. The battery has the highest capacity at 20 degrees Celsius. With increasing temperature, it practically does not change. But when it drops to 0 degrees, the capacity drops the faster, the greater the value of the discharge current. This decrease in capacitance is associated with a decrease in the discharge voltage, which is caused by an increase in polarization and ohmic resistance. The resistance increases due to the small volume of electrolyte.

So, the composition of the alkali (electrolyte) and its concentration significantly affect the characteristics of the battery. The temperature of the formation of salts, crystalline hydrates, ice and other elements depends on this.

If the electrolyte is frozen, then the discharge is generally excluded. Lower value operating temperature Ni-Cd batteries in most cases is minus 20 degrees Celsius. For some types of batteries, the composition of the electrolyte is adjusted, and the lower limit of the temperature range is extended to minus 40 degrees Celsius.

What affects the charge of Ni-Cd batteries?

When charging a sealed nickel-cadmium battery, it is important to limit overcharging. When recharging, the pressure inside the battery increases due to the release of oxygen. So the efficiency of using current drops as you approach the 100th charge.

In the image below, you can see graphs characterizing the dependence of the capacity during the discharge of a cylindrical battery.

Charging of Ni-Cd batteries is allowed in the temperature range of 0-40 degrees Celsius. The recommended interval is 10-30 degrees. The oxygen uptake at the cadmium electrode slows down as the temperature drops, resulting in an increase in pressure. If the temperature is higher than recommended, then the potential rises and oxygen begins to be released very early on the positive oxide-nickel electrode. At the same temperature, oxygen is released the more actively, the greater the charge current. At the same time, the rate of oxygen uptake remains almost unchanged. For this value, this value depends on the design of the battery, or rather, on the transport of oxygen from the positive to the negative cadmium electrode. This is affected by the density of the layout, thickness, structure of the electrodes, as well as the material of the separator and the volume of the electrolyte.

The smaller the thickness of the electrodes and the higher the density of their arrangement, the more efficient the charging process will be. Cylindrical batteries with rolled electrodes are the most efficient in this regard. For them, the charge efficiency almost does not change when the current changes from 0.1 to 1C. Manufacturers call the standard charging mode, as a result of which a battery with a voltage of 1 volt is fully charged in 16 hours with a current of 0.1 of the capacity. Some models, when charged in this mode, require 14 hours. Specific indicators already depend on the design features and volume of the active mass.

All of the above is true for a galvanostatic charge. This is a charge at a constant value of current. But the charge can also be carried out with a smooth or stepwise decrease in current strength at the final stage of charging. Then at the initial stage the current can be set much higher standard value 0.1 of capacity. There is often a real need to increase the charging speed. The problem is solved with the use of batteries, the characteristics of which make it possible to efficiently receive a high-density charge. The current is kept constant throughout the charging process. Also, control systems are being improved that do not allow overcharging the battery.

Cylindrical nickel-cadmium batteries are usually charged in the following modes:

6-7 hours current 0.2 of the capacity;
3-4 hours with a current of 0.3 of the capacity.

When accelerating, it is not recommended to allow a recharge of more than 120-140 percent. Then the capacity will be provided not less than the face value. Ni-Cd accumulators for work in the accelerated modes are charged even faster (about one hour). However, in the latter case, voltage and temperature control is needed. Otherwise, due to the rapid increase in pressure, the process of battery degradation may begin.

After the charge is completed in a sealed battery, oxygen is still being released due to the oxidation of hydroxide ions at the positive electrode. Due to the self-discharge process, the potential decreases, and the process of oxygen evolution gradually decreases and becomes equal to its absorption on the cadmium electrode. Then the pressure decreases. About that, it is disassembled in detail at the specified link.

Operating Nickel-Cadmium Batteries (Ni-Cd)

Gradually, during the operation of nickel-cadmium batteries, changes occur in them that affect performance. These changes cause a gradual drop in battery voltage and a decrease in its discharge capacity.

What factors lead to the failure of Ni-Cd batteries:

Reducing the working surface of the electrodes;
loss of the active mass of the electrodes;
change in the composition and volume of the alkaline electrolyte, as well as its redistribution in the battery;
the occurrence of leaks along the conductors caused by the growth of cadmium dendrites;
processes that are associated with the irreversible consumption of water and oxygen;
breakdown of organic matter.

Changes in the positive electrode (nickel oxide)

After a certain, sufficiently large, number of cycles, the density of the active mass of the positive electrode changes. There is a so-called swelling of the nickel oxide electrode. In addition, its strength decreases. As a result, the quality of contact between the active mass and the electrode base decreases. As a result, the electrical conductivity of the electrode decreases and the battery capacity decreases.

The decrease in the strength of the positive electrode is caused mainly due to regular overcharging. As mentioned above, this is accompanied by the release of oxygen in the sealed battery case. In batteries with cermet electrodes, these changes are observed to a much lesser extent. During the operation of nickel-cadmium batteries, an increase in active mass crystals is observed. This leads to a decrease in the working surface of the electrodes and a drop in capacitance.

Changes in the negative electrode (cadmium)

On the cadmium electrode, the main process causing its degradation is the migration of the active mass. In a Ni-Cd battery that has been used for a long time, the active mass of the negative electrode can be found both in the separator and on the positive electrode. As a result, there is a loss of the active mass, as well as blocking of the surface layer of the negative electrode.

This impairs the access of the alkaline electrolyte deep into the electrode. As a result, the internal resistance of the battery increases. The migration of the active mass and the growth of dendrites through the separator to the positive electrode causes short circuits and an increase in self-discharge. As in the oxide-nickel electrode, so in the cadmium one, the crystals grow larger, and the active mass swells.

The service life of a nickel-cadmium battery is also reduced by other irreversible processes. In particular, due to the high oxidation potential of the positive electrode, organic impurities are oxidized on it. These are special stabilizing and activating additives in this type of battery. The cermet base of the electrode during its oxidation consumes water and releases nickel hydroxide (Ni (OH) 2).

An increase in pressure in a nickel-cadmium battery also has a detrimental effect on the condition of the battery. When the capacitance of the cadmium electrode decreases, the balance of the capacitances of the positive and negative plates changes. As a result, conditions are created for hydrogen evolution. At low speed recombination, hydrogen begins to accumulate and there is a threat of a sharp increase in pressure. This pattern is often seen in fast charge. For prismatic and disk models of Ni-Cd batteries, the case may be deformed at elevated pressure. The tightness can be preserved, but the density of the assembly is broken, the internal resistance of the battery increases and the discharge voltage decreases.

It is worth remembering that hydrogen also accumulates when the battery is constantly discharged to 0 volts. In addition, there is nitrogen inside the battery, which gets there when sealed. So, inside there is still a reduction of nitrates in the electrolyte. It also causes an increase in pressure. Alkaline nickel-cadmium batteries have emergency valve to relieve pressure. But this is done once, since irreversible changes occur in the chemical element.

The alkaline electrolyte also contributes to the drop in the performance of a Ni-Cd battery. More precisely, a change in its composition and volume. As a result of a change in the structure and swelling of the electrodes, electrolyte is withdrawn. As a result, the internal resistance of the battery increases. The composition of the electrolyte changes gradually. Compared to the initial state, the volume of carbonates may increase significantly. The electrical conductivity of the electrolyte drops, and the battery parameters deteriorate during discharge. This is especially noticeable at low temperatures.

How operation and temperature affect the degradation process

One of the most important factors influencing the degradation process of a nickel-cadmium battery is temperature. For every ten degrees rise in temperature, chemical processes are accelerated by two to four times.

The effect of temperature becomes even more pronounced as the charge current increases, as this causes the battery to heat up when overcharged. The decrease in capacitance of the cadmium electrolyte at low temperature will exceed the decrease in capacitance of the positive electrode. This imposes some restrictions on the use of batteries in the northern regions. In such a situation, when charging, the rate of hydrogen evolution increases.

On the degradation process of nickel-cadmium batteries big influence renders the nature of exploitation. What is included here:

depth and mode of discharge;
charging mode;
time interval m / y charge and discharge (if cycling is continuous);
periods of storage and operation.

In the graph below, you can see the duration of the battery in cycles depending on the depth of discharge.

It should be noted that Ni-Cd batteries have a fairly high resistance to accidental overcharging. If the overdischarge occurs infrequently, then hydrogen is easily recombined. When the polarization is removed, the battery voltage is restored.

With constant recharging of nickel-cadmium batteries, it is necessary to provide a current equal to 0.03-0.05 of the rated capacity. If the battery is constantly operated in this mode, then in addition to the magnitude of the current, the OS temperature also affects. When the temperature rises, the production of oxygen increases. This accelerates battery degradation. In order to function with continuous recharging (temperature 50-55 degrees Celsius), special models were created cylindrical accumulators. They have roll-type electrodes with a service life of at least 4 years. These batteries have an adjusted composition of the electrolyte and have been prepared to accelerate the absorption of gases.

If you discharge a Ni-Cd battery after a long charge, then its capacity will be slightly lower than that of batteries charged from scratch. But this phenomenon is temporary and the capacity will return to normal after several charge-discharge cycles.

Marking alkaline nickel-cadmium batteries (Ni-Cd)

Marking Ni-Cd batteries may look like this:

40 HK, K, L, H; 250 P(P), K

The symbols stand for the following:

40 - the number of batteries in the battery or battery pack;
NK, K - nickel cadmium type battery (designation NK corresponds to TU 16-90 ILVE.563330.001TU, designation K corresponds to IEC 623, GOST R IEC 60623-2002);
L, H - type of Ni-Cd battery depending on the discharge mode (L - long discharge mode, H - short discharge mode);
250 - the value of the nominal capacity (ampere-hours);
R(P) - plastic version of the storage battery tank;
K - frame version of the battery pack.

Pros and cons of nickel-cadmium batteries (Ni-Cd)

In conclusion, let us briefly recall the advantages and disadvantages of nickel-cadmium batteries.

Advantages of Ni-Cd batteries

A large number of charge-discharge cycles (more than 1000);
Long shelf life regardless of the degree of charge;
Fast and easy way to charge;
Withstand a serious load;
It is possible to work at low temperatures;
Well suited for harsh operating conditions;
Maintain capacity at low temperatures;
They are inexpensive.

Cons of Ni-Cd batteries

The memory effect and the need for work to eliminate it;
Sufficiently high degree of self-discharge;
Low energy density compared to other types of batteries;
Toxicity of materials. This is especially true for cadmium. In a number of countries, the manufacture and use of such batteries is prohibited. Requires special equipment and technology for their disposal.

That's all that at this point I wanted to tell you about nickel-cadmium batteries. If you have questions or additions on the topic, then leave them in the comments.

Published in

A cadmium battery is a popular source of energy that is used to complete household appliances. They are classified as alkaline types. They are equipped with those units and devices, which cannot include other models.

Negative and positive current-carrying terminals are introduced into the composition of nickel-cadmium batteries, for the separation of which a separator is used. Inner part filled with alkaline electrolytic composition. The case for nickel-cadmium batteries is prepared from a special metal, hermetically sealed.

In order to ensure better contact, foil is used to prepare the electrodes, which is characterized by a small thickness. To design a separator, which is concentrated between the terminals in nickel-cadmium batteries, woven raw materials are used. After all, it does not interact with an alkaline electrolyte.

Boron is used to connect the battery to other nickel-cadmium power sources. The composition of the nickel-cadmium battery device includes welded joints, which provide a tight connection.

Advantages of Nickel Cadmium Power Supply

The number of discharge and charge cycles reaches 1,000 or more.
The period of storage of such devices is long. At the same time, the degree of charge of the unit does not affect this indicator.
The technology for charging nickel-cadmium batteries is relatively simple. It can also be implemented by novice motorists.
It is possible to operate such power sources in winter, in harsh conditions.
The capacity does not decrease even at sub-zero temperatures.

Negative sides

Devices have such property as "memory effect". To eliminate it, there is a need for certain measures.
The level of self-discharge is increased.
If we compare cd batteries with other power sources, we can distinguish their low energy density.
For the preparation used toxic components. Therefore, some states do not use such batteries, do not manufacture them.
For the disposal of such units, appropriate equipment is used. In our country, facilities for recycling and processing are being prepared for nickel-cadmium units.

Charging, discharging nickel-cadmium batteries

Discharge process

The discharge parameters of the power source largely depend on the design features, characteristics of the electrodes and current leads. They also predetermine the magnitude of the voltage and internal resistance.

Bit parameters depend on:

Features and structures of the separator.
Build quality.
The amount of electrolytic composition with which the body is filled.
Other.

With a long discharge of a nicd source, experts recommend using disk batteries, which are supplemented with large-sized pressed leads. Therefore, with a small increase in current, the discharge capacitance, as well as the voltage, decreases. In order to optimize this indicator, the thickness of the leads is reduced, the number is increased.

The maximum capacitance value is observed at room temperature. A further increase in temperature does not affect this parameter. Negative temperature provokes a decrease in the discharge voltage, an increase in the discharge current.

The use of screwdrivers, which are equipped with nickel-cadmium power sources, requires caution in winter.

Charging process

In the process of charging ni cd batteries, it is necessary to introduce charge restrictions. Indeed, in the process of recharging inside the case, pressure rises, oxygen is produced, and the current application coefficient decreases.

How to charge ni cd battery? In order to fully restore the charge, a capacity of 150-160 percent must be reported. Temperature range - 0-+35 degrees. If you do not take into account the temperature range, then the pressure will increase. Through the emergency valve will be released oxygen mixture. Therefore, it is important to determine in advance how to properly charge the battery.

A discharged nickel-cadmium battery is charged in various modes. The charging time depends on which mode is selected.

A current of 0.2 of the total capacity for 7 hours.
A current of 0.3 of the total capacity is not more than 4 hours.

When charging the unit in accelerated mode (with a current of 0.4 of the available capacity), overcharging is prohibited, as this will lead to a decrease in capacity. You can set how much the power source is charged using the appropriate devices. When working with currents, an ammeter is used. To determine the number of volts, use a voltmeter or multimeter.

Charger for nickel-cadmium batteries

To charge ni cd batteries, reversible and automatic chargers are used.

The automatic ni cd charger is easy to use. With it, you can recharge 2-4 batteries for a screwdriver or other household appliances. After placing the battery in the memory, the mode, number, is set. After that, the unit is connected to the network.

Automatic models are equipped with indicators that determine the state of the charged power sources when working with current. Such devices are also suitable for discharging ni cd batteries.

Pulse chargers have a more complex design. They can be used when working with significant current. Since they are classified as professional units, before use, it is studied how to charge the power source, how to set the required parameters.

Reverse (pulse) models are suitable for cyclic supply of charge and discharge current. When discharging and charging, the parameters of current and voltage are predetermined.

Features of use

Long-term operation affects the functioning and performance of cadmium-nickel batteries. The following leads to deterioration in performance and failure:

The working surface of the conductive leads is reduced.
The active mass of conductive terminals is significantly reduced.
The alkaline electrolytic composition changes the composition, is incorrectly redistributed along the power source.
Leakage occurs through conductive elements. As a result, the discharge of a charged power source occurs quickly enough.
The consumption of liquid, oxygen increases. With excessive release of oxygen, the process becomes irreversible.
Organic compounds begin to decompose.

Recovery of nickel-cadmium batteries

The procedure for restoring nickel-cadmium batteries, which are used to complete a screwdriver, other portable unit, takes some time. Since the cost of such batteries is high, you should study the features before implementation.

In fact, we restore the nickel-cadmium battery of a screwdriver impulse current, which is served within 2-4 seconds. The current value exceeds the capacitance parameters by 10 or more times.

Before restoring the battery, certain elements and tools are prepared:

Efficient power supply with strong current indicators. A car battery is used as a battery.
Clamps.
Wires.
A multimeter that controls voltage.
Protective items.

The recovery procedure includes certain activities:

The handheld tool unit or individual battery has a positive and negative contact.
Using clips or alligator clips, as well as pieces of wire, minuses are attached.
The other end of the wire is pressed against the positive contact. The duration of the wire contact is 1-2 seconds (it can be increased up to 3 seconds). Such actions take a little time. Upon contact, make sure that the wires do not stick to the block, battery.

After one cycle, the voltage level is measured using a multimeter. As soon as the voltage is restored, they proceed to a set of capacitance. In order to restore and repair the power supply, 2-4 cycles are performed.

This technique brings the expected effect only for a short time. This is because the electrolytic composition changes, and its volume also changes. As a result, batteries cannot be used as sources for a long time.

Modernized methodology

In order to restore nickel-cadmium batteries with your own hands, as well as to ensure their long-term operation, the following steps are performed:

All batteries are carefully checked, the voltage is measured. Those elements on which the voltage is close to zero are withdrawn.
Holes are prepared in the body with the help of an appropriate tool in order to pour 1 cm3 of distilled water.
The power supplies are allowed to stand for a short period of time, after which the voltage is rechecked.
If the battery performance is restored, then the formed holes are treated with sealant, soldering.
The block is completed with batteries, it is repeatedly charged. The portable tool is ready for use as soon as the indicator on the charger changes color. For these purposes, it is worth using pulse chargers, which are distinguished by extensive functionality, high-quality equipment.
At zero voltage, distilled water is introduced into the battery again.
The procedure is repeated until a positive result is achieved.

Storage Features

For cadmium batteries, the operating rules have been prepared by specialists. The instructions describe how to store power supplies. Several basic rules have been identified.

You can store ni cd sources only when they are completely discharged. For these purposes, use chargers that are equipped with the appropriate function. Incandescent lamps with the appropriate number of amperes are also used for emptying.

Batteries that are properly prepared can be stored for a long time. Temperature changes do not affect the condition and performance.

Rooms are used to store nickel-cadmium batteries. After all, temperature fluctuations do not provoke discharge, the launch of irreversible processes.

Although nickel-cadmium batteries are stored for a long time, at a certain stage there is a need for disposal. To do this, contact the organization that performs such processes.

The efficiency of nickel-cadmium batteries is difficult to overestimate. They complete the portable tools used in life and in the industry. With proper handling, compliance with safety regulations and operating conditions, the period of use exceeds five years.

Video about Nickel Cadmium Batteries

(NiMH) and lithium-ion (Li-ion) batteries, which must be kept charged.

Invention history

In 1899 Waldmar Jungner From Sweden, he invented the nickel-cadmium battery, in which nickel was used as a positive electrode, and cadmium as a negative electrode. Two years later, Edison proposed an alternative design, replacing cadmium with iron. Due to the high (compared to dry or lead acid batteries) cost, the practical application of nickel-cadmium and nickel-iron batteries has been limited.

After the invention in 1932 Schlecht And Ackerman The pressed anode has undergone many improvements resulting in higher load current and increased durability. The well-known sealed nickel-cadmium battery today became available only after the invention Newman (Neumann) fully sealed element in 1947.

Operating principle

The principle of operation of nickel-cadmium batteries is based on a reversible process:

2NiOOH + Cd + 2H 2 O ↔ 2Ni(OH) 2 + Cd(OH) 2 E 0 = 1.30 V.

The nickel electrode is a paste of nickel hydroxide mixed with a conductive material and deposited on a steel mesh, while the cadmium electrode is a steel mesh with spongy cadmium pressed into it. The space between the electrodes is filled with a jelly-like composition based on wet alkali, which freezes at -27°C. Individual cells are assembled into batteries with a specific energy of 20–35 W*h/kg and a long service life - several thousand charge-discharge cycles.

Options

Theoretical energy content: 237 Wh/kg
Specific energy intensity: 45–65 Wh/kg
Specific energy density: 50–150 Wh/dm³
Specific power: 150…500 W/kg
EMF = 1.37
Operating voltage = 1.35 ... 1.0 V
Normal charging current \u003d 0.1 ... 1 C, where C is the capacity
Service life: about 100-900 charge/discharge cycles.
Self-discharge: 10% per month
Operating temperature: -50…+40 °C

Currently, the use of nickel-cadmium batteries is very limited for environmental reasons, so they are used only where the use of other systems is impossible, namely, in devices characterized by high discharge and charging currents. A typical flying model battery can be charged in half an hour and discharged in five minutes. Due to the very low internal resistance, the battery does not heat up even when charging at high currents. Only when the battery is fully charged does a noticeable warm-up begin, which is used by most chargers as a signal for the end of charging. Structurally, all nickel-cadmium batteries are equipped with a durable sealed case that can withstand the internal pressure of gases in harsh operating conditions.

The discharge cycle starts at 1.35 V and ends at 1.0 V (respectively 100% capacity and 1% remaining capacity)

The electrodes of nickel-cadmium batteries are made both by stamping from a sheet and by pressing from a powder. Pressed electrodes are more technologically advanced, cheaper to manufacture and have higher operating capacity, and therefore all household batteries have pressed electrodes. However, pressed systems are subject to the so-called "memory effect". The memory effect occurs when a battery is charged before it actually runs out. An "extra" electrical double layer appears in the electrochemical system of the battery and its voltage decreases by 0.1 V. A typical controller of a device using a battery interprets this decrease in voltage as a complete discharge of the battery and reports that the battery is "bad". There is no real reduction in power consumption, and a good controller can ensure that the battery capacity is fully utilized. However, in a typical case, the controller prompts the user to perform more and more charging cycles. And this leads to the fact that the user, with the best of intentions, “kills” the battery with his own hands. That is, we can say that the battery fails not so much from the “memory effect” of pressed electrodes, but from the “forgetfulness effect” of inexpensive controllers.

Household nickel-cadmium battery, discharged and charged with weak currents (for example, in a remote control remote control TV), quickly loses capacity, and the user considers it to be out of order. Similarly, a battery that has been on charge for a long time (for example, in an uninterruptible power supply system) will lose capacity, although its voltage will be correct. That is, you cannot use a nickel-cadmium battery in buffer mode. However, one deep discharge cycle and subsequent charging will fully restore battery capacity.

During storage, NiCd batteries also lose capacity, although they retain output voltage. To avoid incorrect sorting when removing batteries from storage, it is recommended to store them in a discharged form - then after the first charge the batteries will be completely ready for use. To completely discharge the battery and equalize the voltages on each discharged element, you can connect a chain of two silicon diodes and a resistor to each element, thereby limiting the voltage to 1-1.1 V per element. In this case, the voltage drop across each silicon diode is 0.5–0.7 V, so you need to select the diodes for the chain manually, using, for example, a multimeter. After long-term storage of the battery, it is necessary to carry out two or three charge / discharge cycles with a current numerically equal to the nominal capacity (1C) so that it enters the operating mode and works with full efficiency.

Areas of use

Small-sized nickel-cadmium batteries are used in various equipment as a replacement for a standard galvanic cell, especially if the equipment consumes high current. Since the internal resistance of a nickel-cadmium battery is one to two orders of magnitude lower than that of conventional manganese-zinc and manganese-air batteries, power is delivered more stable and without overheating.

Nickel-cadmium batteries are used in electric cars (as traction), trams and trolleybuses (to power control circuits), river and sea vessels. They are widely used in aviation as on-board batteries for aircraft and helicopters. They are used as power sources for stand-alone screwdrivers / screwdrivers and drills, however, there is a tendency to replace them with high-current batteries of various lithium systems.

Despite the development of other electrochemical systems and the tightening of environmental regulations, nickel-cadmium batteries remain the main choice for highly reliable devices that consume high power, such as diving lights.

Long shelf life, relative undemanding to constant care and control, the ability to work stably in frost down to -40 ° C and the absence of the possibility of ignition during depressurization in comparison with lithium, low specific gravity in comparison with lead and cheapness in comparison with silver-zinc, less internal resistance, greater reliability and frost resistance in comparison with NiMH cause the still widespread use of nickel-cadmium batteries in military equipment, aviation and portable radio communications.

Disc nickel-cadmium batteries

Nickel-cadmium batteries are also available in a hermetic "tablet" design, like batteries for watches. The electrodes in such a battery are two pressed thin tablets of active mass, folded into a bag with a separator and a flat spring and rolled into a nickel-plated steel case with a diameter of a coin. They are used to power various, mostly low-power, loads (current C / 10-C / 5). Allow only small charging currents, not more than C / 10, since the recombination of the released gases must have time to occur inside the case. Due to the closed design, they allow a long recharge with continuous recombination and the release of excess energy in the form of heat. The voltage of such a battery is lower than that of a non-sealed one and changes little during the discharge process due to an excess of the active mass of the cathode created to accelerate the recombination of oxygen.

Disk batteries (as a rule, in batteries of 3 pieces in a common shell, of a size similar to the Soviet D-0.06) were widely used in personal computers manufactured in 1980–90, in particular -286/386 and early 486, to power non-volatile memory settings (CMOS NVRAM) and real time clock when mains power is off. The battery life in this mode was several years, after which the battery, in most cases soldered into the motherboard, had to be replaced. With the development of CMOS technology and the decrease in power consumption of NVRAM and RTC, batteries have been replaced by disposable lithium cells with a capacity of about 200 mAh (CR2032, etc.), installed in latched sockets and easily replaced by the user, with a similar period of continuous operation.

In the USSR, disk batteries were practically the only batteries available for general sale (except for car batteries and, later, NiCd AA size for 450 mAh). Apart from individual elements, a 9-volt battery of seven D-0.1 batteries was offered with a connector similar to the Krone, which, however, was not included in the power compartment of all radios for which it was intended. Only the simplest chargers with a current of C / 10 were supplied, charging the battery or battery in about 14 hours (the time was controlled by the user).

Name battery	Diameter , mm	Height, mm	Voltage, IN	Capacity, Ah	Recommended discharge current, mA	Application
D-0.03	11,6	5,5	1,2	0,03	3	cameras , Hearing Aids
D-0.06	15,6	6,4	1,2	0,06	12	cameras, photographic exposure meters, hearing aids, dosimeters
D-0.125	20	6,6	1,2	0,125	12,5	rechargeable electric flashlights [ ] , miniature radios
D-0.26	25,2	9,3	1,2	0,26	26	rechargeable electric flashlights, flashlights, calculators (B3-36)
D-0.55	34,6	9,8	1,2	0,55	55	flashlights, rechargeable electric flashlights, calculators (B3-34)
7D-0.125			8,4	0,125	12,5	battery replacement Crown

Manufacturers

NiCd batteries are produced by many companies, including such large international companies as GP Batteries, Samsung (under the Pleomax brand), VARTA, GAZ, Konnoc, Metabo, EMM, Advanced Battery Factory, Panasonic/Matsushita Electric Industrial, Ansmann, etc. Among domestic manufacturers can be called NIAI (created on the basis of the Central Battery Laboratory, 1946), Kosmos, CJSC Experimental Plant NIIKhIT, CJSC NIIKhIT-2.

Safe disposal

The melting of the waste products of NiCd batteries takes place in furnaces at high temperatures, cadmium becomes extremely volatile under these conditions, and if the furnace is not equipped with a special trapping filter, toxic substances (for example, cadmium vapours) are emitted into external environment, poisoning the surrounding areas. As a result, disposal equipment is more expensive than lead battery disposal equipment.

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Literature

Khrustalev D. A. Accumulators. M: Emerald, 2003.
Fedotov G. A. Electrical and electronic devices for photography. L.: Energoatomizdat, 1984.
. Current sources are chemical. Terms and Definitions.
.

Notes

There are or external references in this article or section, but the sources of individual statements remain unclear due to the lack of footnotes.

Statements not , may be questioned and removed. You can improve the article by adding more precise references to the sources.



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An excerpt characterizing the Nickel-cadmium battery

We'll clean it up for you. - And Timokhin, not yet dressed, ran to clean.
The prince wants.
- Which? Our prince? - voices began to speak, and everyone hurried so that Prince Andrei managed to calm them down. He thought it better to pour himself in the barn.
“Meat, body, chair a canon [cannon fodder]! - he thought, looking at his naked body, and shuddering not so much from the cold, but from disgust and horror, incomprehensible to him, at the sight of this huge number of bodies rinsing in a dirty pond.
On August 7, Prince Bagration wrote the following in his camp at Mikhailovka on the Smolensk road:
“Dear sir, Count Alexei Andreevich.
(He wrote to Arakcheev, but he knew that his letter would be read by the sovereign, and therefore, as far as he was capable of doing so, he considered his every word.)
I think that the Minister has already reported on leaving Smolensk to the enemy. It hurts, sadly, and the whole army is in despair that the most important place was abandoned in vain. I, for my part, asked him personally in the most convincing way, and finally wrote; but nothing agreed with him. I swear to you on my honor that Napoleon was in such a bag as never before, and he could lose half the army, but not take Smolensk. Our troops have fought and are fighting like never before. I held on with 15,000 for over 35 hours and beat them; but he did not want to stay even 14 hours. It's a shame and a stain on our army; and he himself, it seems to me, should not live in the world. If he conveys that the loss is great, it is not true; maybe about 4 thousand, no more, but not even that. At least ten, how to be, war! But the enemy lost the abyss ...
What was it worth to stay two more days? At least they would have left; for they had no water to drink for men and horses. He gave me his word that he would not retreat, but suddenly sent a disposition that he was leaving into the night. Thus, it is impossible to fight, and we can soon bring the enemy to Moscow ...
Rumor has it that you think about the world. To reconcile, God forbid! After all the donations and after such extravagant retreats, make up your mind: you will turn the whole of Russia against you, and each of us, out of shame, will make him wear a uniform. If it has already gone like this, we must fight while Russia can and while people are on their feet ...
You have to lead one, not two. Your minister may be good in the ministry; but the general is not only bad, but trashy, and he was given the fate of our entire Fatherland ... I, really, go crazy with annoyance; Forgive me for writing boldly. It can be seen that he does not love the sovereign and wishes the death of all of us who advise to make peace and command the army to the minister. So, I am writing you the truth: prepare the militia. For the minister in the most skillful way leads the guest to the capital. Adjutant Wolzogen is giving the whole army a big suspicion. He, they say, is more Napoleonic than ours, and he advises everything to the minister. I am not only courteous against him, but I obey like a corporal, although older than him. It hurts; but, loving my benefactor and sovereign, I obey. It’s only a pity for the sovereign that he entrusts such a glorious army. Imagine that with our retreat we lost people from fatigue and more than 15 thousand in hospitals; and if they had attacked, it would not have happened. Say for God's sake that our Russia - our mother - will say that we are so afraid and why we give such a good and zealous Fatherland to bastards and instill hatred and shame in every subject. What to be afraid of and who to be afraid of?. It's not my fault that the minister is indecisive, a coward, stupid, slow and everything has bad qualities. The whole army is crying completely and scolding him to death ... "

Among the innumerable subdivisions that can be made in the phenomena of life, one can subdivide them all into those in which the content predominates, others in which the form predominates. Among these, in contrast to rural, zemstvo, provincial, even Moscow life, one can include life in St. Petersburg, especially salon life. This life is unchangeable.
Since 1805 we have been reconciling and quarreling with Bonaparte, we have made constitutions and butchered them, and the salon of Anna Pavlovna and the salon of Helene were exactly the same as they had been one seven years, the other five years ago. In the same way, Anna Pavlovna spoke with bewilderment about the successes of Bonaparte and saw, both in his successes and in the indulgence of European sovereigns, a malicious conspiracy, with the sole purpose of unpleasantness and anxiety of that court circle, of which Anna Pavlovna was a representative. In the same way, with Helen, whom Rumyantsev himself honored with his visit and considered a remarkably intelligent woman, just as in 1808, so in 1812, they spoke with enthusiasm about a great nation and a great person and looked with regret at the break with France, which, according to the people who gathered in the salon Helen, should have ended in peace.
Recently, after the arrival of the sovereign from the army, there was some excitement in these opposing circles in the salons and some demonstrations were made against each other, but the direction of the circles remained the same. Only inveterate legitimists from the French were accepted into Anna Pavlovna's circle, and here the patriotic idea was expressed that there was no need to go to the French theater and that the maintenance of the troupe costs as much as the maintenance of the whole building. The military events were eagerly followed, and the most beneficial rumors for our army were spread. In Helen's circle, Rumyantsev, French, rumors about the cruelty of the enemy and the war were refuted and all Napoleon's attempts at reconciliation were discussed. In this circle, those who advised too hasty orders to prepare for departure to Kazan to court and women's educational institutions, under the patronage of the Empress mother, were reproached. In general, the whole matter of the war was presented in Helen’s salon as empty demonstrations that would very soon end in peace, and the opinion of Bilibin, who was now in St. think they'll solve the problem. In this circle, ironically and very cleverly, although very carefully, they ridiculed the Moscow delight, the news of which arrived with the sovereign in St. Petersburg.
In Anna Pavlovna's circle, on the contrary, they admired these delights and talked about them, as Plutarch says about the ancients. Prince Vasily, who occupied all the same important positions, was the link between the two circles. He went to ma bonne amie [his worthy friend] Anna Pavlovna and went dans le salon diplomatique de ma fille [to his daughter's diplomatic salon] and often, during incessant moving from one camp to another, he got confused and told Anna Pavlovna that it was necessary to speak with Helen, and vice versa.
Shortly after the arrival of the sovereign, Prince Vasily began talking with Anna Pavlovna about the affairs of the war, cruelly condemning Barclay de Tolly and being indecisive about whom to appoint as commander in chief. One of the guests, known as un homme de beaucoup de merite [a man of great merit], told that he had seen Kutuzov, who was now elected chief of the St. that Kutuzov would be the person who would satisfy all the requirements.
Anna Pavlovna smiled sadly and noticed that Kutuzov, apart from troubles, had given nothing to the sovereign.
“I spoke and spoke in the Assembly of the Nobility,” interrupted Prince Vasily, “but they did not listen to me. I said that his election to the head of the militia would not please the sovereign. They didn't listen to me.
“It’s all some kind of mania to frond,” he continued. - And before whom? And all because we want to ape stupid Moscow delights, ”said Prince Vasily, confused for a moment and forgetting that Helen had to laugh at Moscow delights, while Anna Pavlovna had to admire them. But he immediately recovered. - Well, is it proper for Count Kutuzov, the oldest general in Russia, to sit in the chamber, et il en restera pour sa peine! [His troubles will be in vain!] Is it possible to appoint a man who cannot sit on horseback, falls asleep at the council, a man of the most bad morals! He proved himself well in Bucarest! I'm not talking about his qualities as a general, but is it possible at such a moment to appoint a decrepit and blind person, just blind? The blind general will be good! He doesn't see anything. Play blind man's blind man... sees absolutely nothing!
Nobody objected to this.
On the 24th of July it was absolutely right. But on July 29, Kutuzov was granted the princely dignity. Princely dignity could also mean that they wanted to get rid of him - and therefore the judgment of Prince Vasily continued to be correct, although he was in no hurry to express it now. But on August 8, a committee was assembled from General Field Marshal Saltykov, Arakcheev, Vyazmitinov, Lopukhin and Kochubey to discuss the affairs of the war. The committee decided that the failures were due to differences of command, and, despite the fact that the persons who made up the committee knew the sovereign's dislike for Kutuzov, the committee, after a short meeting, proposed appointing Kutuzov commander in chief. And on the same day, Kutuzov was appointed plenipotentiary commander of the armies and the entire region occupied by the troops.
On August 9, Prince Vasily met again at Anna Pavlovna's with l "homme de beaucoup de merite [a person of great dignity]. L" homme de beaucoup de merite courted Anna Pavlovna on the occasion of the desire to appoint Empress Maria Fedorovna as a trustee of the women's educational institution. Prince Vasily entered the room with the air of a happy winner, a man who had achieved the goal of his desires.
– Eh bien, vous savez la grande nouvelle? Le prince Koutouzoff est marechal. [Well s, you know the great news? Kutuzov - field marshal.] All disagreements are over. I'm so happy, so glad! - said Prince Vasily. – Enfin voila un homme, [Finally, this is a man.] – he said, significantly and sternly looking around at everyone in the living room. L "homme de beaucoup de merite, despite his desire to get a place, could not help but remind Prince Vasily of his previous judgment. (This was impolite both in front of Prince Vasily in Anna Pavlovna's drawing room, and in front of Anna Pavlovna, who was just as joyfully received the news; but he could not resist.)
- Mais on dit qu "il est aveugle, mon prince? [But they say he is blind?] - he said, reminding Prince Vasily of his own words.
- Allez donc, il y voit assez, [Eh, nonsense, he sees enough, believe me.] - said Prince Vasily in his bassy, quick voice with a cough, that voice and cough with which he resolved all difficulties. “Allez, il y voit assez,” he repeated. “And what I am glad about,” he continued, “is that the sovereign has given him complete power over all the armies, over the entire region, a power that no commander in chief has ever had. This is another autocrat,” he concluded with a victorious smile.
“God forbid, God forbid,” said Anna Pavlovna. L "homme de beaucoup de merite, still new to court society, wishing to flatter Anna Pavlovna, shielding her former opinion from this judgment, said.
- They say that the sovereign reluctantly transferred this power to Kutuzov. On dit qu "il rougit comme une demoiselle a laquelle on lirait Joconde, en lui disant: "Le souverain et la patrie vous decernent cet honneur." [They say that he blushed like a young lady who would have read Joconde, while told him: "The sovereign and the fatherland reward you with this honor."]
- Peut etre que la c?ur n "etait pas de la partie, [Maybe the heart did not quite participate,] - said Anna Pavlovna.
“Oh no, no,” Prince Vasily interceded fervently. Now he could not give in to Kutuzov to anyone. According to Prince Vasily, not only Kutuzov was good himself, but everyone adored him. “No, it cannot be, because the sovereign was so able to appreciate him before,” he said.
“God only grant that Prince Kutuzov,” said Anpa Pavlovna, “takes real power and does not allow anyone to put spokes in his wheels – des batons dans les roues.”
Prince Vasily immediately realized who this nobody was. He whispered:
- I know for sure that Kutuzov, as an indispensable condition, said that the heir to the Tsarevich should not be with the army: Vous savez ce qu "il a dit a l" Empereur? [Do you know what he said to the sovereign?] - And Prince Vasily repeated the words, as if said by Kutuzov to the sovereign: “I cannot punish him if he does badly, and reward him if he does well.” ABOUT! this is the smartest man, Prince Kutuzov, et quel caractere. Oh je le connais de longue date. [and what character. Oh, I've known him for a long time.]
“They even say,” said l “homme de beaucoup de merite, who still did not have court tact, “that the most illustrious made it an indispensable condition that the sovereign himself did not come to the army.
As soon as he said this, in an instant Prince Vasily and Anna Pavlovna turned away from him and sadly, with a sigh at his naivety, looked at each other.

While this was happening in Petersburg, the French had already passed Smolensk and were moving closer and closer to Moscow. The historian of Napoleon Thiers, like other historians of Napoleon, says, trying to justify his hero, that Napoleon was unwittingly drawn to the walls of Moscow. He is right, as are all historians who seek an explanation of historical events in the will of one person; he is just as right as the Russian historians who assert that Napoleon was attracted to Moscow by the skill of the Russian generals. Here, in addition to the law of retrospectiveness (recurrence), which represents everything that has passed as a preparation for an accomplished fact, there is also reciprocity that confuses the whole thing. A good player who loses at chess is sincerely convinced that his loss was due to his mistake, and he looks for this mistake at the beginning of his game, but forgets that in his every step, throughout the whole game, there were such mistakes that no one his move was not perfect. The error to which he draws attention is noticeable to him only because the enemy took advantage of it. How much more complicated than this, then, is the game of war taking place under certain conditions of time, and where it is not the will alone that guides lifeless machines, but where everything springs from an innumerable clash of various arbitrarinesses?

All batteries are designed for repeated deep charge-discharge.

The positive electrode (cathode) contains nickel oxide-hydroxide NiOOH with graphite powder (5-8%), and the negative electrode (anode) contains metallic cadmium Cd in powder form.

Batteries of this type are often referred to as rolled, since the electrodes are rolled into a cylinder (roll) together with a separating layer, placed in a metal case and filled with electrolyte. The separator (separator), moistened with electrolyte, isolates the plates from each other. It is made of non-woven material, which must be resistant to alkali. The most common electrolyte is potassium hydroxide KOH with the addition of lithium hydroxide LiOH, which promotes the formation of lithium nickelates and increases the capacity by 20%.

at the anode:
Cd (tv) + 2OH - (l) → Cd (OH) 2 (tv) + 2e -

At the cathode:
2Ni III O(OH) (solid) + 2H 2 O (l) + 2e – → 2Ni II (OH) 2 (solid) + 2OH – (l)

The total discharge equation for nickel cadmium battery:

2 NiOOH + Cd + 2 H 2 O ↔ 2 Ni(OH) 2 + Cd(OH) 2

Terminal voltage 1,2 IN

Advantages:

Gives a relatively strong current, which is why it is used, for example, in cordless working tools,

Possibility of fast and simple charge, even after long-term storage of the battery;
a large number of charge / discharge cycles: with proper operation - more than 1000 cycles;
good load capacity and the ability to operate at low temperatures;
long periods of storage at any degree of charge.

Flaws: cadmium toxicity; "memory" effect.

http://www.ixbt.com/mobile/accumulators-mem.shtml

Nickel-metal hydride battery (NiMH)

The anode is an alloy of nickel with some other metal (La, Li); the alloy as a whole is denoted by the letter M. Such a material makes it possible to retain hydrogen atoms (H) in the voids of the crystal lattice.

The cathode is a mixture of basic oxide and nickel hydroxide.

The voltage at the terminals is about 1.2 V.

Used in older types of mobile phones. Available for sale NiMH batteries standard battery size (AA, etc.), which have recently supplanted in this area NiCd accumulators.

Advantages: high specific capacity, relatively light, less toxic compared to NiCd battery.

Flaws: relatively fast self-discharge; more expensive than the above batteries.

charge only completely discharged batteries;
You should not place a charged battery for additional recharging, as this significantly reduces the period of its use;
it is not recommended to remove an undercharged battery from the charger;
Do not leave Ni-Cd and Ni-MH batteries in the charger after the end of the charge for a long time, since the charger continues to charge them even after a full charge, but only with a much lower current. Long-term presence of Ni-Cd- and Ni-MH batteries in the memory leads to their overcharging and deterioration of parameters;
Batteries must be at room temperature before charging. Charging is most efficient at an ambient temperature of +10°C to +25°C.

Store Ni-MHbatteries need to be in a cool dry place at a temperature slightly below room temperature, charged by 40%. Once every 1-2 months, you should recharge, discharge and charge again at 30-60% capacity. Storage for up to 5 years is acceptable.