According to the chemical principle and characteristics of NiMH battery, the application range of NiMH battery can be known. The details are shown below.
Chemical principles
The "metal" part of NiMH battery is actually an intermetallic compound. Many kinds of intermetallic compounds have been used in the manufacture of Ni MH batteries, mainly divided into two categories. The most common 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), B is zirconium (Zr) or nickel (Ni), plus some chromium (CR), cobalt (CO), iron (FE) and / or manganese (MN). [5]
All these compounds play the same role: reversibly forming metal hydrides. When the battery is charged, the hydrogen ion (H +) in the potassium hydroxide (KOH) electrolyte will be released and absorbed by these compounds 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 return to their original place through the opposite process.
characteristic
• rated voltage = 1.2V
• voltage when fully charged (charging voltage) = about 1.4 ~ 1.45v
• termination voltage = 0.9 ~ 1.0V
• energy / weight = 60 ~ 120 WH / kg (watt hour / kg)
• energy / volume = 140 ~ 300 WH / L (watt hour / L), i.e. 504 ~ 1188kj / kg (kJ / kg)
• power / weight = 250 ~ 1000 W / kg
• self discharge rate = generally 20 ~ 30% per month, depending on the temperature, and the low self discharge model is 10 ~ 30% per year
• charge discharge efficiency = 66%
• number of charge discharge cycles = 500 ~ 5000
• common battery models = AAAA, AAA, AA, a, s, D, SC
application
Consumer electronics
Ni MH batteries are widely used in consumer electronics.
Because of self discharge, the old NiMH battery will lose power within months or even weeks after charging. It can only be used for the purpose of requiring power in a short time. For example, the infrared remote controller or clock of household appliances is not suitable.
The new low leakage NiMH battery can basically replace most of the equipment that originally used alkaline batteries. Only some old and low power consumption electronic products (such as old radios) will have a decline in performance when using NiMH batteries because of voltage problems.
Remote control toys
Some NiMH batteries with particularly high power have larger capacity, output battery and power than Ni Cd batteries, so they replace Ni Cd batteries in electric remote control toys (such as remote control cars).
Hybrid vehicle
High power NiMH batteries are also used in oil electric hybrid vehicles. If the vehicle uses special charging and discharging procedures, the probability that the vehicle needs to replace Ni MH rechargeable batteries in the first ten years is very low.
Pure battery powered vehicle
Although it is heavier than lithium-ion batteries in weight, some brands of pure battery powered vehicles still use NiMH batteries.
