Spherical hydrogen storage alloy for capacitive nickel-hydrogen power battery and preparation method thereof

Abstract

The invention belongs to the technical field of rare earth functional materials, and in particular relates to a capacitive type nickel-hydrogen battery spherical hydrogen storing alloy and a preparation method thereof. A spherical product is obtained by coating the outer surfaces of multiple type AB5 hydrogen storing alloys with sub-micron grade magnesium powder under the action of HPMC conductive glue, wherein the HPMC conductive glue comprises a conductive substance, a binding agent and HPMC. The sub-micron grade magnesium powder has the particle granularity D50 being less than or equal to 2 micron and Dmax being less than or equal to 10 micron. The spherical hydrogen storing alloy is prepared by adding the sub-micron grade magnesium powder into the type AB5 hydrogen storing alloys, and performing vacuum heat treatment, acid pickling, washing by pure water, coating by the HPMC conductive glue and spray granulation, the service lifecycle and alloy power of an electrode can be improved, the material machinability is good, the normal-temperature plastic package can be realized, large package can be realized, the production efficiency is greatly improved, the package cost is reduced, and important economic significance is realized.

Description

Technical field [0001] The invention belongs to the technical field of rare earth functional materials, and in particular relates to a spherical hydrogen storage alloy for a capacitive nickel-hydrogen power battery and a preparation method thereof. Background technique [0002] With the acceleration of urbanization and the rapid development of smart cities, smart transportation (such as trolley buses, high-speed rails, EMUs, pure electric buses) has become a major feature of a city or between cities, and power batteries, as an important component of smart transportation, require It has high power, long life, environmental protection and recyclability, wide environmental adaptability, high safety and high energy density. Capacitive nickel-metal hydride power battery, as one of the vehicle power batteries, has the advantages of adjusting and balancing the application of lanthanum and cerium, creating a high-end application industry chain for rare earths, fast charge and discharge, ...

AI Technical Summary

Problems solved by technology

[0003] However, the capacitive Ni-MH power battery still has certain defects in terms of power, such as charging and discharging at 50-100C or 2000-4000A current, and the hydrogen storage alloy used in the negative electrode is an important factor determining the power of the power battery. Therefore, it is of great economic significance to develop a hydrogen storage alloy with corrosion resistance, high catalytic activity, strong reaction kinetics and rate capability.

[0004] The most widely used hydrogen storage alloy is AB 5 type, while the AB 5 Type alloys usually require surface treatment such as acid and alkali before they can be applied to power batteries, such as nickel-metal hydride batteries for hybrid vehicles. The hydrogen storage alloys are usually treated with lye to make the surface rich in nickel, improve reactivity, and obtain Higher power growth, but this method causes greater damage to the morphology of alloy particles, and increases engineering difficulty for the subsequent pole piece manufacturing process; some units also use sintering technology to obtain greater catalytic activity, but the sintered pole pieces are deformed High resistance, the pole piece must be relatively thin, and the sintered pole piece is relatively brittle, while the mechanical strength increases, the flexibility decreases, and the hydrogen storage alloy has a large expansion rate during the charge and discharge process, and the sintered pole piece lacking flexibility Easy to pulverize, reduce battery life

Therefore, the area of ​​the sintered pole piece is relatively small, the specific energy of the battery mass is ≤50Wh / Kg, the capacity is ≤100Ah, and the lifespan is ≤500 times. The application field is also limited to fields that do not care about cost and special power requirements, such as laser equipment

In addition, there are scientific research units to add Co 3 o 4 AB 5 The research on the electrochemical performance of the alloy shows that the specific capacity has been improved to a certain extent, but the Co 3 o 4 Directly added to the alloy powder and used directly, there are problems such as poor dispersion, low adhesion, and difficulty in exerting its catalytic performance. Therefore, the alloy powder still needs surface treatment to improve its rate performance

[0005] "Adding Co" published by "Battery" 3 o 4 AB 5 Co 3 o 4 Directly added to the alloy powder and used directly, it has a certain effect on the specific capacity and catalytic performance of the alloy powder, but the catalytic performance is limited, and the adhesion is not strong and the dispersion is uneven

[0006] in AB 5 Adhesion of Nanoscale Co on Hydrogen Storage Alloys by Vacuum Heat Treatment 3 o 4 and CeO 2 , to prepare AB 5 / Co 3 o 4 / CeO 2 (Patent CN 103215485 A), which greatly improves the catalytic activity of the hydrogen storage alloy, thereby increasing its battery power, but the disadvantage of its patent is that the cost of nano-scale metal oxides is relatively high

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