Nickel-Metal Hydride Battery

Among other batteries, Ni Mh batteries are often used. These batteries are characterized by high technical characteristics that allow them to be used as efficiently as possible. This type of battery is used almost everywhere, below we will consider all the features of such batteries, as well as analyze the nuances of operation and well-known manufacturers.

What is a nickel metal hydride battery?

To begin with, it is worth noting that nickel-metal hydride is a secondary power source. It does not produce energy; recharging is required before work.

It consists of two components:

• anode - nickel lithium hydride or nickel lanthanum;
• the cathode is nickel oxide.

Electrolyte is also used to energize the system. The optimal electrolyte is potassium hydroxide. This is an alkaline power source according to modern classification.

This type of battery has replaced the nickel-cadmium battery. The developers managed to minimize the disadvantages characteristic of earlier types of batteries. The first industrial designs were put on the market in the late 80s.

At the moment, it has been possible to significantly increase the density of stored energy in comparison with the first prototypes. Some experts believe that the density limit has not yet been reached.

Principle of operation and device Ni Mh battery

For starters, it's worth considering how a NiMh battery works. As already mentioned, this battery consists of several components. We will analyze them in more detail.

The anode here is a hydrogen-absorbing composition. It is capable of absorbing a large amount of hydrogen, on average, the amount of absorbed element can exceed the volume of the electrode 1000 times. To achieve complete stabilization, lithium or lanthanum is added to the alloy.

Cathodes are made from nickel oxide. This allows you to get a quality charge between the cathode and the anode. In practice, a variety of types of cathodes for technical execution can be used:

• lamella;
• ceramic-metal;
• metal-smelting;
• pressed;
• foam nickel (foam polymer).

The largest capacity and service life are characterized by foam polymer and metal-cathode cathodes.

The conductor between them is alkali. It uses concentrated potassium hydroxide.

Battery design may vary depending on goals and objectives. Most often, this is a rolled up anode and cathode, between which there is a separator. There are also options where the plates are placed alternately, shifted by a separator. A mandatory design element is a safety valve, it is triggered by an emergency increase in pressure inside the battery to 2-4 MPa.

What are the Ni-Mh batteries and their specifications

All nickel-metal hydride batteries are Rechargeable Battery (translates to rechargeable battery). This type of battery is produced in different types and forms. All of them are intended for a variety of purposes and tasks.

There are batteries that are currently almost never used, or are used only to a limited extent. Such batteries can be attributed to the “Krona” type, it was marked 6KR61, before they were used everywhere, now they can only be found in old equipment. Type 6KR61 batteries had a voltage of 9v.

We will analyze the main types of batteries and their characteristics that are used now.

• AA Finger batteries. The capacity ranges from 1700-2900 mA / h.
• AAA. Pinky batteries. Sometimes labeled MN2400 or MX2400. Capacity - 800-1000 mA / h.
• FROM. Medium sized batteries. They have a capacity in the range of 4500-6000 mA / h.
• D. The most powerful type of battery. Capacity from 9000 to 11500 mA / h.

All listed batteries have a voltage of 1.5v. There are also some models with a voltage of 1.2v. The maximum voltage is 12v (due to the connection of 10 1.2v batteries).

Pros and Cons of a Ni-Mh Battery

As already mentioned, this type of battery replaced the older varieties. Unlike analogues, they significantly reduced the "memory effect". They also reduced the amount of substances harmful to nature during the creation process.

The pluses include the following nuances.

• They work well at low temperatures. This is especially important for equipment operated on the street.
• Reduced "memory effect." But, nevertheless, he is present.
• Non-toxic batteries.
• Higher capacity in comparison with analogues.

Also, batteries of this type have disadvantages.

• Higher self-discharge rate.
• More expensive to manufacture.
• After about 250-300 charge / discharge cycles, the capacity begins to decline.
• Limited lifetime.

Where are nickel metal hydride batteries used?

Due to the large capacity, such batteries can be used everywhere. Whether it is a screwdriver, or a sophisticated measuring device, in any case, a similar battery will provide it with enough energy without any problems.

In everyday life, such batteries are most often used in portable lighting devices and radio equipment. Here they show good performance, while maintaining optimal consumer properties for a long time. Moreover, both disposable elements and reusable ones that are regularly recharged from external power sources can be used.

Another application is appliances. Due to their sufficient capacity, they can also be used in portable medical equipment. They work well in tonometers and glucometers. Since there are no voltage surges, there is no effect on the measurement result.

Many measuring instruments in technology have to be used on the street, including in winter. Here metal hydride batteries are simply irreplaceable. Due to the small reaction to negative temperatures, they can be used in the most difficult conditions.

Terms of Use

It should be borne in mind that the new batteries have a sufficiently large internal resistance. To achieve a slight decrease in this parameter, the battery should be discharged several times “to zero” at the beginning of use. To do this, use chargers with this function.

Attention! This does not apply to disposable batteries.

Often you can hear the question of how many volts you can discharge a nickel-metal hydride battery. In fact, it can be discharged almost to zero parameters, in this case the voltage will not be enough to maintain the operation of the connected device.

It is even recommended sometimes to wait for a full discharge. This reduces the "memory effect." Accordingly, the battery life is extended. Otherwise, the operation of batteries of this type does not differ from analogues.

Do I need to rock Ni-Mh batteries

An important stage of operation is the buildup of the battery. Nickel-metal hydride batteries also require this procedure. This is especially important after prolonged storage in order to restore capacity and maximum voltage.

To do this, you need to discharge the battery to zero. Please note that electric shock is required. In the end, you should get the minimum voltage. So you can revive the battery, even if a lot of time has passed from the date of manufacture. The longer the battery lay, the more swing cycles are required. Usually, it takes 2-5 cycles to restore capacitance and resistance.

How to Recover Ni Mh Battery

Despite all the advantages and features of such batteries, there is still a "memory effect".If the battery began to lose performance, then you should restore it.

Before you start, you need to check the battery capacity. Sometimes it turns out that it is almost impossible to achieve improved performance, in which case you just need to replace the battery. We also check the battery for a malfunction.

The work itself is similar to the buildup. But, here they do not achieve a full discharge, but simply lower the voltage to a level of 1v. 2-3 cycles are required. If during this time it was not possible to achieve the optimal result, it is worth recognizing the battery as unusable. When charging, you need to withstand the Delta Peak parameter for a specific battery.

Storage and disposal

It is worth storing the battery at a temperature close to 0 ° C. This is an optimal condition. It is also necessary to take into account that storage should take place only during the expiration date, these data are indicated on the packaging, but the interpretation may differ from different manufacturers.

This type of battery is recycled. It is recommended not to dispose of the batteries, but to hand them in for recycling, so rare elements will be recycled.

Manufacturers worth paying attention to

All battery manufacturers produce Ni-Mh batteries. In the list below you can see the most famous companies offering similar products.

• Energizer
• Varta;
• Duracell
• Minamoto;
• Gp;
• Eneloop;
• Camelion
• Panasonic
• Irobot
• Sanyo.

If you look at the quality, everyone has it about the same. But, one can single out Varta and Panasonic batteries, they have the most optimal price-quality ratio. Otherwise, you can use any of the listed batteries without any restrictions.