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Composition of Ni-MH battery

Time:2020-12-26 Views:238

  At present, batteries have been used in more and more fields. In most cases, we only know nickel, chromium and other elements that more people know about the composition of batteries. Let’s briefly talk about nickel-hydrogen batteries today. The ingredients.

Composition of Ni-MH battery(图1)


  Civilian nickel-hydrogen batteries belong to low-voltage nickel-hydrogen batteries, with Ni(OH)2 as the positive electrode, hydrogen storage alloy as the negative electrode, and potassium hydroxide alkaline aqueous solution as the electrolyte. The external specifications of Ni-MH batteries are roughly the same as those of Ni-Cd batteries. In terms of performance indicators, there are many differences, but Ni-MH batteries have some unique advantages, the most important manifestation is the higher specific energy density of Ni-MH batteries (that is, batteries of the same volume, Ni-MH batteries are more The capacity of cadmium batteries is larger). Theoretically, the energy density of nickel-hydrogen batteries is 1.5-2 times that of nickel-cadmium batteries; there are also nickel-hydrogen batteries that are environmentally friendly. Ni-MH batteries do not use metal "cadmium" and do not use toxic substances. , Will not pollute the environment; and nickel-metal hydride batteries basically do not have a "memory effect". Of course it does not contain zinc and manganese.

  The chemical components of NiMH batteries:

  The "metal" part of the nickel-hydrogen battery is actually an intermetallic compound. Many types of intermetallic compounds have been used in the manufacture of nickel-metal hydride batteries, and they are mainly divided into two categories. The most common type is AB5. A is a mixture of rare earth elements (or) plus titanium (Ti); B is nickel (Ni), cobalt (Co), manganese (Mn), (or) and aluminum ( Al). The "multi-component" electrodes of some high-capacity batteries are mainly composed of AB2, where A is titanium (Ti) or vanadium (V), and B is zirconium (Zr) or nickel (Ni), plus There are some chromium (Cr), cobalt (Co), iron (Fe) and/or manganese (Mn). All these compounds play the same role: they can be transformed into metal hydrides. When the battery is charged, hydrogen ions (H+) in the potassium hydroxide (KOH) electrolyte will be released. These compounds absorb it to avoid the formation of hydrogen (H2) to maintain the internal pressure and volume of the battery. When the battery is discharged, these hydrogen ions will go back to their original places through the reverse process.

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