Forming method of nickel-metal hydride battery

Abstract

The invention provides a forming method of a nickel-metal hydride battery. The method comprises laying an assembled battery at room temperature for a certain time; precharging the battery with a current of 0.01-0.1 C until reaching 10%-40% of the rated capacity; laying the battery at a high-temperature environment of 30-70 DEG C for 60-144 hours; performing formation and grading on the battery, wherein the grading comprises multiple charging and discharging steps, and the first charging and discharging step includes charging the battery with a current of 0.005-0.1 C and a current of 0.1-0.3 C sequentially, deeply discharging the battery with a current of 0.05-0.5 C to be 0.8 V lower than a cut-off voltage for at least once, and discharging the battery in a constant voltage mode to be 0.05 C lower than a cut-off current, and the others forming charging and discharging steps perform constant-current charging and constant-current timed discharging through a current lower than 0.5 C. The forming method of the nickel-metal hydride battery can effectively reduce self-charging and self-discharging of the battery, improve the charge retention ratio of the battery by 3%-6%, improve OCV (open circuit voltage) maintenance of the battery and increase the voltage maintaining time.

Description

technical field [0001] The invention relates to a method for forming a nickel-hydrogen battery. Background technique [0002] Ni-MH battery is a traditional product. When the batteries produced by the chemical formation method are selected for shipment later, their low-voltage ratios are relatively high, and the OCV maintenance is poor. Especially when the battery is not charged, the OCV drops even more. As a result, a large part of batteries cannot be shipped due to low voltage and large self-discharge, resulting in low output rate. The rapid voltage drop and poor OCV maintenance are mainly due to the current formation method, the battery cannot completely convert the CoO and CoOOH in the positive electrode during the formation charge and discharge process, and at the same time cannot convert the small amount of Co contained in CoO The powder is completely converted into CoOOH, and a small amount of Co powder is dissolved in the lye and finally attached to the surface of t...

AI Technical Summary

Problems solved by technology

[0002] Ni-MH battery is a traditional product. When the batteries produced by the chemical formation method are selected for shipment later, their low-voltage ratios are relatively high, and the OCV maintenance is poor. Especially when the battery is not charged, the OCV drops even more. As a result, a large part of batteries cannot be shipped due to low voltage and large self-discharge, resulting in low output rate

The rapid voltage drop and poor OCV maintenance are mainly due to the current formation method, the battery cannot completely convert the CoO and CoOOH in the positive electrode during the formation charge and discharge process, and at the same time cannot convert the small amount of Co contained in CoO The powder is completely converted into CoOOH, and a small amount of Co powder dissolves in the lye and finally attaches to the surface of the separator, thereby forming a Co bridge in the battery and increasing the self-discharge rate of the battery.

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