APR 13, 2021 Pageview：70
A nickel metal hydride battery or a NiMH battery is a rechargeable (secondary) type of battery. A NiMH battery is similar to a nickel-cadmium NiCd battery because both of these batteries have a similar positive electrode. Both make use of nickel oxide hydroxide NiOOH. Whereas, both types of batteries have different negative electrodes. A nickel metal hydride NiMH battery’s negative electrode is made up of an alloy and the negative electrode of a nickel-cadmium NiCD battery is made up of cadmium.
For around 50 years, Nickel-Cadmium batteries used to be the preference for powering up all electrical and electronic devices. They used to produce satisfactory outputs but there was a significant problem with the toxicity of the nickel-cadmium battery. In the 1990s, nickel metal hydride batteries took over the rule of nickel-cadmium batteries and nickel metal hydride batteries became the preference for all types of devices.
Most of the characteristics of a Nickel-metal hydride battery are similar to its forerunner the nickel-cadmium battery. The capacity of NiMH batteries is two to three times higher than the capacity of Nickel-Cadmium batteries that will be of the same size and same output ratings but having higher energy density.
NiMH batteries are used in small portable devices and are also used in electric and hybrid-electric automobiles. However, they are now being replaced by lithium-ion batteries in the applications of automobile systems.
Since NiMH batteries are still popular and in use, it is very important to know about their basics of operation and problems. Before you have to make your choice for the right type of NiMH battery, you need to know about its lifespan, charger, and suppliers.
Rechargeable NiMH Battery Lifespan
NiMH batteries are rechargeable batteries and can maintain their healthy operations for hundreds of charge cycles if charged with due care. Their ability to hold hundreds of charge cycles without any problem makes their service equal to the service of hundreds of alkaline batteries that can only hold a single or few charge cycles.
The shelf life of a NiMH battery will depend and vary according to the rating of the load it was attached to and on the temperature at which it will be stored. Also, the battery’s shelf life depends on the type of manufacturer. Generally, the typical lifetime of a NiMH battery with appropriate usage is around 5 years or sometimes more.
To increase the lifespan of your battery when storing it for shorter periods of time, you should opt for a storage location that has low humidity, an absence of corrosive gases, and a temperature range of -20 to +45 degrees celcius. Storing batteries in storage locations having high humidity and temperatures outside the range will decrease the lifespan of the battery by risking rusting of metallic parts and battery leakages due to chemical reactions inside the battery.
Similarly, to increase the lifespan of your battery when storing it for longer periods, you have to take care of the battery’s self-discharge mechanism that triggers due to inactivity for longer periods. Temperature ranges from +10 to +30 degrees Celcius are suitable for storing batteries for longer periods.
Rechargeable NiMH Battery Charger
NiMH and NiCd batteries have a lot of similar characteristics. The discharging pattern of a NiMH battery is similar to that of its antecedent. However, the NiMH battery has a unique characteristic of being blinkered to overcharging. Overcharging of a NiMH battery can result in the reduction of its charging capacity.
In the account of this problem, the charger for NiMH batteries has to be intelligent so that they can identify when the battery is completely charged. Smart chargers for NiMH batteries are capable of detecting voltage knocks in the output voltage of the NiCd battery when it has been charged. A similar mechanism is applied in the NiMH chargers but the voltage knock-in NiMH batteries are smaller, therefore, difficult to detect for the charger.
NiMH chargers have a combination of features installed in them to detect the end of battery charging. Most of the chargers contain the three basic full-charge detection mechanisms, NDV, temperature rise, and timer charging. Additionally, most of the NiMH chargers operate on the extra-charge mechanisms which include a 30-minute extra charge of 0.1C.
Some smart chargers for NiMH batteries make use of the fast-charge technique of 1C. After a specific time or when the cell voltage reaches a specified level, a cool-down process starts while the charging continues with low current levels. As the charging progresses, the charger reduces the current levels further to avoid over-charging. This process of current reduction goes on simultaneously until the battery is charged to its full capacity. This method is called ‘step differential charging’.
Most people do not use the designated chargers for NiMH batteries. They use common chargers that do not contain the features to prevent overcharging resulting in damage to the battery through overcharging. This damage causes the lifespan of the battery to be reduced for a significant number of charges and the batteries perform even less than their lifespan.
Rechargeable NiMH Battery Suppliers
NiMH batteries are now common because of their expanded use in portable electrical/electronic devices and automobile systems. This increased popularity of the NiMH batteries has resulted in their increased market. A lot of the leading market companies of the world are now working on producing basic and high-end future technology NiMH batteries that can find their way into the market through various applications.
There are various suppliers of NiMH batteries around the world. However, if you are considering buying one for yourself you should always conduct market research and then make the decision according to your budget. The leading producers and suppliers of NiMH batteries in the world are currently, Energizer, Panasonic, and AmazonBasics. They have a variety of NiMH batteries that they offer along with warranties.
Most of these batteries are made in China, Japan, and Korea and all contain more or less the same components. Local companies and suppliers source these batteries directly from these countries.
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