Battery Case Production Line Case 5

3. Ni-MH battery

Nickel-hydrogen batteries are alkaline batteries, and their characteristics are similar to nickel-cadmium batteries, but there is no heavy metal pollution problem, so they are called "green batteries". The electrode uses nickel compound and another metal compound, and the electrolyte is potassium hydroxide.

At present, the performance indicators that nickel-metal hydride batteries can achieve are: the nominal voltage of the single battery is 1.2V, the specific energy is 70-95Wh/kg, the specific power is 200-300W/kg, the energy efficiency is as high as 70%, and the cycle life exceeds 1000 times .

The advantages of nickel metal hydride batteries are: specific power and specific energy are higher than lead-acid batteries and nickel-cadmium batteries, and the cycle life is the highest among vehicle batteries; fast charging and deep discharging performance are good, charging efficiency is high, and there is no heavy metal pollution .

The disadvantages of Ni-MH batteries are: high cost, the price is 5-8 times that of lead-acid batteries with the same capacity, low voltage of single battery, and large self-discharge loss.

In the past few years, with the industrialization of hybrid electric vehicles, nickel metal hydride batteries have received very general attention. Many companies regard Ni-MH batteries as the battery of choice for hybrid vehicles.

In addition to Toyota's Corolla Twin Engine, Camry, Prius, Honda's Civic HEV, CRZ and other hybrid models, there are also Ford's Ford Escape and Chevrolet's Chevrolet Malibu.

Ni-MH batteries are very close to our daily life. From the early sounds, it is very common to hear small electrical appliances such as rechargeable toothbrushes. The positive pole is a nickel-hydrogen compound, and the negative pole is a metal hydride. Compared with the energy density and charge-discharge times Lead-acid batteries have been greatly improved, and the electrolyte is non-flammable, safe, and the manufacturing process is mature. Before building cars, BYD was the second largest manufacturer of nickel-metal hydride batteries in the world.

However, because Ni-MH batteries have average charging efficiency, have charging and memory effects, and have low operating voltage (high-voltage fast charging cannot be used), they are not suitable for the single power source of the car, and are suitable for auxiliary engine work. Later, with the widespread implementation of lithium batteries, it gradually withdrew from the automotive field.