Nimh battery provide longer-lasting power and stay charged longer when not in use. This article will comprehensively introduce nickel-metal hydride batteries from the aspects of their definition, common uses, advantages and disadvantages, and development status.
1.What is nimh battery?
Nimh battery, full name nickel metal hydride battery, is a high-performance rechargeable battery. Compared with ordinary alkaline batteries, nimh battery have higher energy density, longer battery life cycle, and lower self-discharge rate. This means it provides longer-lasting power and stays charged longer when not in use.
2. The structure of nimh battery
Nickel-metal hydride (Ni-MH) batteries are synthesized from hydrogen ions and metallic nickel. They have 30% more power reserve than nickel-cadmium batteries. They are lighter than nickel-cadmium batteries, have a longer service life, and are non-polluting to the environment. They are now mainly used in for hybrid electric vehicles.
The disadvantage of nickel-metal hydride batteries is that the price is much higher than that of nickel-cadmium batteries, and their performance is worse than that of lithium-ion batteries. The metal part in nickel-metal hydride batteries is metal hydride, which is mainly divided into two categories, namely AB5 and AB2.
The most common one is AB5, “A” means a mixture of rare earth elements or plus titanium (Ti); “B” means nickel (Ni), cobalt (Co), manganese (Mn), or aluminum (Al) . The electrodes of some high-capacity batteries containing multiple components are mainly composed of AB2, “A” represents titanium (Ti) or vanadium (V); B represents zirconium (Zr) or nickel (Ni), plus some chromium ( Cr), cobalt (Co), iron (Fe) and manganese (Mn).
3. Working principle of nimh battery
The negative electrode of the nickel-hydrogen battery uses a hydride electrode with hydrogen storage material as the active material, the positive electrode uses a nickel hydroxide electrode (nickel electrode for short), and the electrolyte is a potassium hydroxide aqueous solution.
When the nickel-metal hydride battery is charged, the hydrogen ions in the potassium hydroxide electrolyte will be released, and these compounds will absorb it to avoid the formation of hydrogen gas to maintain the pressure and volume inside the battery. When the battery is discharged, these hydrogen ions will return to their original place through the reverse process.
The charging process of nickel-cadmium and nickel-metal hydride batteries is very similar. Both require constant current charging to prevent the battery from overcharging.
The charger charges the battery with constant current and detects the battery voltage and other parameters at the same time. In order to avoid damaging the battery, fast charging cannot be started when the battery temperature is too low.
When the battery temperature is lower than 10℃, it should be switched to trickle charging mode. Once the battery temperature reaches the specified value, charging must be stopped immediately.
4.Nimh battery model description
Usually the AAA, AA, C, D, N, F, SC and other marks on the battery body are American model marks. In China, except for several types of batteries that are called by “number”, others still use the American naming method.
In addition, the model of secondary lithium battery is represented by five digits (cylindrical) or six digits (square), such as 14500, 103450, etc.
Flat-head batteries refer to batteries with a flat positive electrode and no protrusions. They are mainly suitable for battery cores used for spot welding of battery packs. Generally, the same type of pointed battery (which can be used as a single battery power supply) is 0.5mm more in height than a flat battery.Â
Some batteries are not the main models such as AAA, AA, A, SC, C, D, N, F, etc., but have 1/3, 2/3, 1/2, 2/3, 4/5, 5/4 , 7/5, etc. These scores represent the ratio of the battery body height to the standard model battery height. For example, 2/3AA means that the battery height is 2/3 of a general AA-type battery; 4/5A means that the battery height is 4/5 of a general A-type battery.
According to the International Electrotechnical Commission (IEC) standards, the nickel-cadmium and nickel-metal hydride battery logos consist of the following five parts.
- Battery type: KR means nickel-cadmium battery; HF means square nickel-metal hydride battery; HR means cylindrical nickel-metal hydride battery.
- Battery size: including cylindrical battery diameter/height, square battery width/thickness/height, each value is separated by a slash, the unit is mm.
- Discharge characteristic symbols: L means that the suitable discharge current rate is within 0.5C; M means that the suitable discharge current rate is within the range of 0.5 ~ 3.5C; H means that the suitable discharge current rate is within the range of 3.5 ~ 7.0C; X means that the battery can Works at high rate discharge current of 7 ~ 15C.
- High temperature battery symbol: represented by T.
- Type of battery connecting piece: CF means no connecting piece; HH means battery with series connecting piece; HB means battery with parallel connecting piece.
For example, HF18/07/49 represents a square nickel-metal hydride battery with a width of 18mm, a thickness of 7mm, and a height of 49mm; KRMT33/62CF represents a nickel-cadmium battery with a discharge rate between 0.5 ~ 3.5C. It is a high-temperature series single battery with no connecting piece. Diameter 33mm, height 62mm.
5.Characteristics of nimh battery
- Nimh battery have long life and stable performance, providing long-lasting power support. They can withstand multiple charge and discharge cycles, are not prone to losing capacity, have high durability and reliability, and meet users’ long-term use needs.
- Nimh battery focus on compactness and lightness in appearance design and are suitable for various devices and application scenarios in varios commercial energy storage systems. They are small in size, light in weight, and can be flexibly installed and carried, making it convenient for users to use and charge in different environments.
- Nimh battery repair and after-sales service have received widespread attention and support. They have lower repair costs and simpler maintenance procedures, and users can easily obtain relevant accessories and charging equipment. The manufacturer also provides professional after-sales service to ensure that users can receive support to solve problems in a timely manner. Here are more information about bess manufacturers.
- Nimh battery also have good environmental adaptability and can work normally in a wide temperature range, making them suitable for various application scenarios.
6.Application scenarios of nimh battery
Nimh battery are widely used in small behind the meter battery storage appliances in our lives, such as remote controls, mobile phones, cameras, etc., to vehicles and power tools in the industrial field. In addition to common electronic devices, nimh battery are also widely used in electric vehicles and energy storage systems.
Compared with traditional gasoline vehicles, electric vehicles using nimh battery can not only reduce pollution emissions, but also provide greater cruising range, bringing convenience to our travels.
In addition to power applications, nimh battery have also become an important part of green energy. By combining with renewable energy devices such as solar panels, nimh battery can store excess electricity, making energy use more efficient.
At night or on cloudy days, this stored electricity can be released to provide stable power support for our lives and work without relying on traditional fossil fuels.
In general, nimh battery, as an advanced rechargeable battery technology, bring many conveniences to our lives and also make important contributions to the future green energy revolution.Â
It not only has high energy density and long life, but also can adapt to different temperature environments and is widely used in various fields. By combining with renewable energy, nimh battery can also provide more environmentally friendly and sustainable energy solutions for our future. Clik here to get more about balcony solar storage system.
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