Introduction to the identification, charging and maintenance of nickel-metal hydride batteries

As a general matter, the actual discharge capacity of a rechargeable battery (nickel-cadmium battery, nickel-hydrogen battery, lithium-ion battery) depends on the charge and discharge mechanism. The charge and discharge currents and the termination voltage are different, and the actual capacity is also different. In order to measure the charge and discharge performance of different batteries, the same charge and discharge mechanism (magnification) is often used for discharge to facilitate comparison.

Charge and discharge rate = charge and discharge current / rated capacity. The discharge rate of the battery is usually 0.1C, 0.2C, and 1.0C, and is often measured by the 0.2C rate. Generally, the higher the magnification, the larger the discharge current, the more severe the polarization of the battery, and the smaller the actual amount of electricity discharged. Understand the charge and discharge rate we can explain the method of marking nickel-metal hydride batteries, because in the IEC standard, nickel-cadmium batteries and nickel-hydrogen batteries are always accompanied, so the two are linked together.

1. According to the IEC standard, the nickel-cadmium/nickel-hydrogen rechargeable battery logo consists of five parts.

1. Battery type: KR stands for nickel-cadmium battery, HF stands for square nickel-hydrogen battery, and HR stands for cylindrical nickel-hydrogen battery.

2. Battery size: including the diameter and height of the round battery; the height, width and thickness of the square battery. Values are separated by slashes in mm.

3. Discharge characteristics: L indicates that the appropriate discharge current is within 0.5C; M indicates that the appropriate discharge current is within 0.5-3.5C; H indicates that the suitable discharge current is within 3.5-7.0C; X indicates that the battery can be at 7C- 15C works at high rate discharge current.

4. High temperature battery symbol: denoted by T.

5. Battery connecting piece means symbol: CF means no connecting piece; HH means that the battery has a connecting piece for pulling series connection; HB means that the battery has a connecting piece for serial connection in series.

E.g:

1. HF18/07/49 indicates a square nickel-hydrogen battery with a width of 18mm, a thickness of 7mm and a height of 49mm;

2. KRMT33/62CF means nickel-cadmium battery, discharge rate between 0.5C-3.5, high-temperature series single cell, no connection piece, diameter 33mm, height 62mm.

Second, the nickel-hydrogen battery is shipped from the factory in the discharge state (that is, no charging state), and can be used after charging for 12 to 14 hours with 0.1C current (constant current charging) before use. Newly purchased, or nickel-metal hydride batteries that have not been used for a long time, require an "activation" time to restore battery power. Therefore, some new NiMH batteries require several charge and discharge cycles to reach their nominal charge. In the daily use process after that, each time the battery is fully recharged, so that the battery life can be guaranteed, usually do not overcharge, do not have to discharge the power for a long time and then save. Because nickel-metal hydride batteries have a memory effect, unlike lithium batteries, they can be recharged at any time.

Third, for the long-term maintenance of nickel-metal hydride batteries, the use of low-frequency pulse - high current charging method is better than the use of trickle charging method to maintain a good battery state.

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