As a kind of rechargeable battery, nickel metal series batteries include nickel-hydrogen batteries, nickel-cadmium batteries, and nickel-zinc batteries. 

Each has its own characteristics. Because its voltage is close to or the same as ordinary carbon and alkaline batteries, it can be recharged repeatedly, providing a small Current, high current discharge performance, wide operating temperature range.

It began to be commercialized in the 1970s. Ni-MH batteries were widely used as power sources for mobile phones, small home appliances, airplane models, car models, and ship models. 

Ni-Cd batteries were used as power sources for emergency lights, power tools, and base stations. 

In 2008, more than 2 million Toyota Honda series vehicles used Ni-MH batteries as their hybrid power.

Most of the patented nickel-metal hydride battery technologies are in the United States, Japan, Switzerland, and other countries.

Engizer in the United States, Panasonic, and FDK in Japan have advanced nickel-hydrogen battery technology and products. 

They have established a complete channel network around the world. 

Most manufacturers in China and overseas manufacturers (Such as OVONIC in the US) obtain patent authorization to produce nickel-metal hydride batteries. 

At the same time, Chinese scientific research experts and engineers are also developing their own patents on nickel-metal hydride battery research. 

They also have their own patents in low-temperature or wide-temperature working conditions and high current discharge. 

Because nickel-cadmium batteries contain heavy metal cadmium, under the requirements of the European Battery Directive. In addition to the only emergency light field, other fields have been required to replace nickel-hydrogen or nickel-zinc, or lithium batteries.

Because of its high voltage, nickel-zinc batteries provide high-drain current discharge. They are used to replace nickel-cadmium batteries on power tools and require special chargers for charging.