KR0139023B1 - Manufacturing method of metal-hydrogen electrode of paste type for nickel/metal hydrogen battery - Google Patents

Abstract

The present invention relates to a method for producing a paste-type metal hydrogen electrode for nickel / metal hydrogen storage batteries, comprising: a grinding step of pulverizing a hydrogen storage alloy in which a small amount of Pd and Ru are added to a V-Ti-Zr-Ni or Mm system; KB to the hydrogen storage alloy powder + PTFE + CMC paste mixing process of adding and mixing the stock solution, the filling process of filling the mixed paste in porous nickel, the drying process of drying the paste filled in porous nickel, and crimping pressing the dried electrode It is to be performed in the order of the molding process.

By providing the present invention, by providing a paste-type electrode manufacturing method that prevents oxidation and poor conductivity of the active material and hardly decreases the electrode capacity, it prevents enormous capacity reduction during electrode production and significantly increases the life of the electrode. It is effective to make a paste-type electrode production of the AB ₂ based alloy known to be impossible by the new paste composition and hydrogen storage alloy composition.

Description

Manufacturing method of paste type metal hydrogen electrode for nickel / metal hydrogen storage battery

1 is a process diagram schematically showing a manufacturing process of a metal hydrogen electrode according to the present invention.

2 is a graph showing the electrode capacity and the life test results of the paste-type Mm-based metal hydrogen electrode of the present invention,

3 is a graph showing the results of positive capacity and life test for a paste-type V-Ti-Zr-Ni-based metal hydrogen electrode.

The present invention relates to a method of manufacturing a paste-type metal hydrogen electrode for nickel / metal hydride batteries, and in particular, a hydrogenated alloy powder and a paste stock solution are mixed and then filled, dried, and pressed in multi-process nickel to form a paste-type metal hydrogen electrode. The present invention relates to a method for producing a paste-type metal hydrogen electrode for nickel / metal hydrogen storage battery, which improves the electrode capacity and workability, prevents dropping due to micronization of hydrogen storage alloy powder, and improves the stability and life of the electrode.

Conventional method of manufacturing a typical metal hydrogen electrode is a method mainly used in the United States OCC Corporation, a method of compression molding and sintering of V-Ti-Zr-Ni-based alloy powder, and Mm alloy powder mixed with a conductive material or micro After encapsulation (microencapsulation), there is a method of preparing an electrode in a paste method by mixing the binder.

The manufacturing method of sintering by compression molding in the manufacturing method of the metal hydrogen electrode has the advantage that the electrode capacity is high because the electrode is manufactured without a conductive material or a binder, but a special high-pressure compression molding device and a sintering device are required, which leads to equipment problems. In addition, as the electrode is manufactured without the binder, it is difficult to handle the electrode, and the electrode active material is dropped due to the micronization of the electrode by repeating the charge / discharge cycle.

In addition, the method of manufacturing the electrode by the paste method has the advantage of increasing the life of the electrode by easy handling of the electrode and less dropping of the electrode active material, but has the disadvantage of reducing the electrode capacity due to the addition of excessive conductive and binder materials. .

The object of the present invention devised in view of the above problems is to prevent the dropping by the micronization of the hydrogen storage alloy which is a problem in the electrode during V-Ti-Zr-Ni-based sintering to improve the stability and life of the electrode, To improve the processability of the electrode and to prevent the addition of excessive conductive materials and binders appearing in the Mm-based hydrogen storage alloy electrode to increase the electrode capacity to provide a method for producing a paste-type metal hydrogen electrode for nickel / metal hydrogen storage batteries have.

The object of the present invention is a pulverizing step of grinding a hydrogen storage alloy in which a small amount of Pd and Ru are added to the V-Ti-Zr-Ni-based and Mm-based, and K.B. + Mixing process of adding and mixing PTFE + CMC paste stock solution, filling process of filling the mixed paste into multi-process nickel, drying process of drying paste filled with porous nickel, and compression molding of dried electrode It is achieved by providing a method for producing a paste-type metal hydrogen electrode for nickel / metal hydride batteries, which is carried out in the order of the compression molding process.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In order to manufacture the paste-type electrode according to the present invention, the composition of the paste is important. In the present invention, in order to prevent oxidation of the electrode, the paste was prepared in an aqueous solution in which oxygen was formed. . The paste stock solution is low in density and has a low amount of KB (ketjen Black), which acts as a conductive material, but AB (Acetylene Black) is 1-10 wt.%, PTFE is 1-20 wt.%, And CM is 0.1-5 wt. It was prepared by mixing%. The paste to be filled in the porous nickel was used by mixing in a composition ratio of 20 ~ 50wt.% Paste stock solution, 50 ~ 80wt.% Hydrogen storage alloy powder. In addition, in the present invention, porous nickel having a three-dimensional structure is used as a current collector, thereby increasing electrode capacity by improving electrical conductivity, and increasing mechanical stability and processability of the electrode by using a three-dimensional current collector. The porous nickel used at this time is 40 ~ 80ppi is suitable so that the hydrogen storage alloy powder having a -325 # size that is commonly used in electrode manufacturing is well filled.

The hydrogen storage alloy powder can be both conventional V-Ti-Zr-Ni-based and Mm-based, but in the present invention is added to 0.005 ~ 1.0wt.%, 0.05 ~ 10wt.% Pd in the existing electrode composition By developing a hydrogen storage alloy to prevent the dissolution and passivation of the electrode and to increase the electrochemical catalytic properties, a long-life, high capacity paste type electrode was developed. Pd and Ru change to an oxide form in alkaline solution, but these materials form mixed oxides with Ti, Ni, Mn, V, etc. to prevent dissolution and passivation of the electrode, which improves the lifetime of the electrode. Its excellent conductivity and electrochemical catalyst properties help to increase electrode capacity and high rate discharge characteristics.

Such a method of manufacturing the paste-type metal hydrogen electrode of the present invention will be described with reference to the manufacturing process diagram of FIG.

First, the hydrogen storage alloy prepared in the arc melting furnace or the high temperature induction melting furnace is adsorbed and desorbed, pulverized to -325 #, and then mixed by adding 20-50 wt.% Of the paste stock solution containing KB + PTFE + CMC. At this time, the paste stock solution is prepared by mixing 1 ~ 10wt.% KB or AB, 1 ~ 20wt.% PTFE, 0.1 ~ 5wt.% CMC with distilled water. The uniformly mixed paste is filled with porous nickel and dried at 120 ° C. for 1 hour. The dried electrode is press-molded at a pressure of 1 to 5 ton / cm ² to finally prepare a paste-type metal hydrogen electrode of the present invention.

The following are examples and comparative examples in which a metal hydrogen electrode was manufactured using the manufacturing method of the present invention and the battery performance was tested, thereby making the present invention more clearly understood.

Example 1

Mm Ni _3.5 Coo, ground to -325 #. ₈ Mno. ₄ Al ₀ . ₃ and MmNi _3.5 Coo. ₈ Mno. ₄ Al ₀ . Hydrogen storage alloy powder of ₃ Pd _0.1 Ru _0.1 composition is pasted at a ratio of 0.3 g of 5 wt.% KB + 10 wt.% PTFE + 2 wt.% CMC paste undiluted solution to lg. The paste was filled in 80 ppi Foamed Ni, dried, and pressed at a pressure of ² ton / cm ² to prepare electrodes A ₁ and A ₂ .

Comparative Example 1

Mm Ni _3.5 Coo of Example 1. ₈ Mno. ₄ Al ₀ . ₃ Hydrogen-alloy powder lg mixed with a ratio of 0.1g of -10μm copper powder and 0.05g of 60% PTFE suspension, coated on 20 # nickel screen, dried, pressurized at 2ton / cm2 and electrode A ₁ Manufacture. Further, the same hydrogen storage alloy powder is 10wt.% Ratio to the copper micro-yen encapsulation mixed at a ratio of 60% PTFE suspension 0.05g respect to 1g of this powder is dried and then coated on 20 # nickel screen, and the 2ton / cm ² Prepare the electrode A ₁ under pressure.

Example 2

To -325 # To each hydrogen storage alloy powder of the composition, paste was mixed at a ratio of 0.3 g of 5 wt.% KB + 10 wt.% PTFE + 2 wt.% CMC paste undiluted solution with respect to 1 g. This paste A charge after a dried and pressed at a pressure of 2ton / cm ² to prepare an electrode B _1, B _2.

Comparative Example 2

Example 2 The hydrogen storage alloy powder was applied to 20 # nickel string, and then pressed at a pressure of 10 ton / cm ² to prepare electrode B ₁ ′.

The battery performance test of the electrode prepared under the above conditions in 30% KOH + 1M LiOH solution is shown in Figures 2 and 3.

As you can see from these results, In the case of the alloy electrode, the electrode prepared by the method of the present invention is about 250mAh / g, including the conductive material and the binder, the electrode A ₁ containing the conductive material and the binder in the electrode of Comparative Example 1 manufactured by a conventional method The capacity increase of about 15-20 mAh / g was shown to be greater than the capacity of 230 mAh / g and 235 mAh / g of 'and A ₁ '. In addition, the life test results up to 200 showed that the electrode life was longer than that of the electrode A ₁ ′, and that the electrode life was almost the same as that of the electrode A ₁ ″. This can increase the electrode capacity because the amount of the conductive material can be reduced due to the excellent conductivity of the hydrogen storage alloy and paste composition of the present invention, and also increases the life of the electrode by preventing dropout due to micronization of the hydrogen storage alloy. .

Also, In the case of the alloy electrode, the capacity of the electrode prepared by the paste method of the present invention was about 260 mAh / g, including the conductive material and the binder, showing a capacity increase of about 25 ~ 30 mAh / g than the electrode of Comparative Example 1, The longevity was shown because the addition of Pd and Ru prevented the dissolution and passivation of the hydrogen storage alloy and the excellent electrochemical catalytic properties.

In the case of an alloy electrode, since the paste method of the present invention, the capacity of the prepared electrode was about 25 mAh / g lower than about 305 mAh / g including the conductive material and the binder, but the electrode life was much longer. In addition, the hydrogen storage alloy of the present invention The electrode prepared with the paste composition was about 330 h / g including the electrode-capacitive conductive material and the binder, and appeared almost the same as the electrode of Comparative Example 1, and the electrode life was much longer.

As described above, the type known as V-Ti-Zr-Ni in so far that is, the use of paste expression method as the electrode production method of the AB ₂ type alloy almost feasibility because capacity reduction due to oxidation and the conductive failure of the electrode active material Although it is known that the present invention is not provided, the present invention provides a paste-type electrode manufacturing method in which the electrode capacity is hardly lowered by preventing oxidation and poor conductivity of the active material, thereby preventing enormous capacity reduction during electrode production and remarkable life of the electrode. It is effective to increase, and it is possible to manufacture a paste type electrode of AB ₂ based alloy, which is known to be impossible with a new paste composition and hydrogen storage alloy composition.

Claims (5)

A grinding step of grinding a hydrogen storage alloy containing a small amount of Pd and Ru in a V-Ti-Zr-Ni-based or Mm-based alloy, and K.B. + PTFE + CMC paste mixing process of adding and mixing the stock solution, the filling process of filling the mixed paste in porous nickel, the drying process of drying the paste filled in porous nickel, and crimping pressing the dried electrode Method for producing a paste-type metal hydrogen electrode for nickel / metal hydrogen storage battery, characterized in that carried out in the order of the molding process. The method of claim 1, wherein the hydrogen storage alloy is Pd is 0.005 ~ 1.0wt.%, Ru is 0.05 ~ 1.0wt.% Is added. The method of claim 1, wherein the paste stock solution is K.B. Or A.B. 1 to 10wt.%, PTFE 1 to 20wt.%, CMC 0.1 to 5wt.% The method for producing a paste-type metal hydrogen electrode for nickel metal hydride batteries, characterized in that. The method of manufacturing a paste-type metal hydrogen electrode for nickel / metal hydrogen storage batteries according to claim 1, wherein the composition ratio of the paste is 50 to 80 wt.% Hydrogen storage alloy powder and 20 to 50 wt.% Paste stock solution. The method of claim 1, wherein the porous nickel is 40 to 80 ppi.