All About Battery Energy

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Nickel-Metal Hydride (NiMH) Batteries

The development of NiMH batteries started in 1967 and was sponsored by Daimler-Benz and Volkswagen for nearly two decades.

These two companies recognised the potential of electric vehicles as a sustainable and environmentally friendly mode of transportation and saw the need for advancements in battery technology to enhance the performance, range, and viability of electric vehicles. Seeking to gain a competitive edge in the emerging electric vehicle market, they decided to sponsor the development of NiMH batteries.

In 1987, the first batteries came out for consumer use. In their current production form, they consist of two electrodes—a positive electrode (cathode) made of nickel oxyhydroxide (NiOOH) and a negative electrode (anode) containing a hydrogen-absorbing alloy, typically based on a mixture of metals like nickel, cobalt, and other rare earth elements. The electrodes are separated by a porous separator and immersed in an alkaline electrolyte, usually potassium hydroxide (KOH).

Battery NiMH - Different types of NiMH Batteries

Battery NiMH – Different types of NiMH Batteries

NiMH batteries offer several advantages over NiCd batteries, including higher energy density, reduced memory effect, and the absence of toxic Cadmium. By 2009, Ni–MH batteries had reached an annual worldwide production of over 1 billion cells. They have become popular for use in portable electronics, hybrid vehicles, power tools and other applications that require rechargeable batteries. They outperform Alkaline batteries in digital cameras and other high-drain devices. In the past, they were even used in the very first electric car ever produced, the General Motors EV1 that came into production in 1996 (initially the car was equipped with lead-acid batteries, which were then changed to NiMH, which improved the car’s range from 100 to 140-160 miles). Today, many hybrid cars are still equipped with NiMH batteries.

Battery NiMH - The battery of a 2016 Toyota Prius Hybrid

Battery NiMH – The battery of a 2016 Toyota Prius Hybrid