Two of the most prominent rechargeable type of batteries are known as the NiCd and NiMH batteries. Both batteries are rechargeable and have been used in electronics, computers and even some cars. There are some significant differences between these two types of batteries; some make one vastly superior over the other.
NiCd is short for nickel cadmium. It gets its name from the two primary elements of the battery. The NiCd battery's creation is attributed to Waldemar Jungner, who first made one in 1899. However, because his work was relatively unknown at the time, mainstream attribution for the invention went to Thomas Edison. NiCd remained for a long time the undisputed main way of recharging a battery.
NiCd reigned supreme for quite a while. Then, NiMH came along. NiMH stands for nickel-metal hydride and was created in 1989 by Masahiko Oshitani, who worked for GS Yuasa Company. The NiMH battery was designed from a nickel/hydrogen hybrid battery and proved to be a powerful battery in its own like, quickly replacing the NiCd for various reasons. The NiMH battery is used for a variety of devices, including small electronics, up to the battery for the Hybrid Toyota Prius.
With every battery, there are environmental concerns. The NiCd, in particular, was highly controversial because the element cadmium is considered one of the most toxic elements in the world. If the battery leaked or exploded, it could cause serious damage and endanger the lives of anyone around them. The NiMH, on the other hand, has no known environmental concerns.
The Memory Effect
The greatest problem with NiCd batteries is what is known as "the memory effect." When an NiCd battery has been charged a certain amount of times, eventually the battery starts thinking its maximum charge is something that it really is not. In other words, the battery says it is 100 percent charged, but in reality it is only 65 percent charged. Although methods do exist to reverse the memory effect, it is important to state that the NiMH batteries do not have this problem.
When NiMH batteries came into the mainstream, people began to realize that the newer NiMH battery far exceeded that of the older NiCd. Furthermore, the NiCd was also much safer then the cadmium-based battery and did not fall victim to the memory effect that was such a staple of the NiCd batteries. In short, the NiMH battery is superior to the NiCd battery.