KR20070102280A - Structure of electrode group for large capacity nickel/metal hydryde secondary battery - Google Patents

Abstract

A structure of an electrode plate assembly for a large capacity nickel/metal storage alloy secondary battery is provided to prevent the pollution in a battery container and to improve the low temperature discharge performance. A structure of an electrode plate assembly for a large capacity nickel/hydrogen storage alloy secondary battery includes an electrode plate assembly comprising a plurality of positive electrode plates(10) connected to a positive electrode pole(30), a plurality of negative electrode plates(20) connected to a negative electrode pole(40), and separating membranes(50) installed at all space between the positive electrode plate and the negative electrode plate, wherein the electrode plate assembly is wrapped by a contractible tube, and the positive electrode plate and the negative electrode plate have a pocket type or a paste type.

Description

STRUCTURE OF ELECTRODE GROUP FOR LARGE CAPACITY NICKEL / METAL HYDRYDE SECONDARY BATTERY}

1 is a perspective view showing the electrode plate group structure of a large capacity nickel / hydrogen storage alloy secondary battery according to the present invention,

FIG. 2 is a perspective view illustrating a structure of a plate group of a conventional high capacity nickel / hydrogen storage alloy secondary battery. FIG.

<Explanation of symbols for main parts of the drawings>

10: positive electrode plate 20: negative electrode plate

30: anode column 30a: terminal

40: cathode column 40a: terminal

50: separator 60: band

70: precursor 80: shrink tube

90: safety control unit

The present invention relates to a structure of the electrode plate group, and more particularly, a large-capacity nickel / hydrogen storage that prevents internal contamination of the precursor and improves low-temperature (-18 ° C) discharge performance in the electrode plate group including the positive plate, the negative plate, and the separator. It is related with the electrode plate group structure of an alloy secondary battery.

In general, a secondary battery means a battery that can be recharged and used again. Lead batteries, alkaline batteries, gas batteries, lithium ion batteries, nickel / cadmium batteries, nickel / hydrogen storage alloy batteries, polymer batteries, etc. Belongs to.

This is a rechargeable battery that can be recharged and used continuously after energy conversion. It combines materials so that the material is oxidized and reduced by the flow of electric current and electricity is generated by oxidation and reduction of the material. It is.

Among these, nickel / hydrogen storage alloy (Ni / MH) secondary batteries can be easily installed in narrow spaces when they are made of light and thin short-sized storage batteries, so they have excellent space utilization and are suitable for various power environments in industrial sites such as large capacity emergency power supplies. .

In addition, nickel / hydrogen storage alloy secondary batteries are environmentally friendly, have high energy density and high output compared to standard capacity because they replace heavy metals of lead and cadmium, prevent the generation of toxic gases due to gas recombination reactions, and suppress dust generation during manufacturing. It can be applied to various loads.

The metal hydrogen compound (MH) of the nickel / hydrogen storage alloy secondary battery is reversibly repeatable for storing and releasing hydrogen as the potential of the alloy is changed. It causes an electrochemical reaction such as

Ni (OH) ₂ + OH- → NiOOH + H ₂ O + e ^_ --- Formula 1,

M + H ₂ O → MH + OH ^_ (M is hydrogen storage alloy) --- Formula 2,

Ni (OH) ₂ + M ↔ NiOOH + MH --- Formula 3,

Formula 1 represents a reaction at a nickel electrode as a positive electrode, Formula 2 represents a reaction at a hydrogen electrode as a negative electrode, and Formula 3 represents a charge and discharge reaction of the entire battery.

Thus, the hydrogen storage alloy (M) used as the negative electrode absorbs the hydrogen generated from the positive electrode active material during charging, and during discharge, the electrochemical reaction is generated from the surface of the alloy while releasing the absorbed hydrogen to generate electricity.

On the other hand, unlike the maintenance-free sealed type (Vented type) nickel / hydrogen storage alloy storage battery can determine the state of the battery by measuring the height of the electrolyte, and can restore the performance of the battery by replenishing the electrolyte when the electrolyte decreases have.

However, in the conventional open nickel / hydrogen storage alloy secondary battery, an electrolyte solution containing an active material eluted from the electrode plate is assembled and assembled into an electrode plate after assembling the electrode group, which is a whole group such as a positive electrode plate, a negative electrode plate, and a separator. The eluate adheres and contaminates in contact with this roll, so that the height of the electrolyte cannot be grasped from the outside.

In addition, when the battery is used at low temperatures (0 ° C. or less), the low temperature electrolyte and the electrode plate react directly to each other, resulting in a decrease in discharge capacity due to an increase in internal resistance.

The present invention has been made in order to solve the problems of the prior art as described above, since the active material eluted from the electrode plate is not contained in the electrolyte, the interior of the precursor is not contaminated, so that the height of the electrolyte can be grasped from the outside, and cooled at low temperatures. It is an object of the present invention to provide a pole plate group structure of a large-capacity nickel / hydrogen storage alloy secondary battery in which the discharge capacity is not greatly reduced because the electrolyte does not directly react with the pole plate.

The pole plate group structure of the large-capacity nickel / hydrogen storage alloy secondary battery of the present invention for achieving the above object,

In the pole plate group structure of the nickel / hydrogen storage alloy secondary battery having a pole plate group consisting of a plurality of positive electrode plates connected to the positive electrode and a plurality of negative electrode plates connected to the negative electrode and a separator installed between the positive electrode and negative electrode plate,

The electrode plate group is wrapped by a shrink tube, and the positive electrode plate and the negative electrode plate are in a pocket type or a paste type.

In addition, the secondary battery is characterized in that the flooded (Flooded) type of the electrolyte is designed in excess.

In addition, the shrink tube is characterized in that made of synthetic resin chemically stable to alkali.

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

1 is a perspective view showing the electrode plate group structure of a large capacity nickel / hydrogen storage alloy secondary battery according to the present invention, Figure 2 is a perspective view showing the electrode plate group structure of a conventional large capacity nickel / hydrogen storage alloy secondary battery.

Prior to explaining the electrode plate group structure of the high-capacity nickel / hydrogen storage alloy secondary battery of the present invention, as shown in FIG. 2, the electrode plate group structure of a general pocket type high capacity nickel / hydrogen storage alloy secondary battery is briefly described below. Take a look.

The positive electrode plate 10 is filled with a nickel hydroxide (Ni (OH) ₂ ) active material in a pocket (pocket) made of a thin steel sheet with a number of fine holes, and then inserted a plurality of pockets in a nickel plated steel sheet to form a pole plate do.

Then, in order to maintain good conductivity, the spot is welded to the nickel plated steel sheet and the pocket, and the whole is pressed.

The negative electrode plate 20 has the same structure as the positive electrode plate 10, but a hydrogen storage alloy (MH Alloy) is used as the active material.

Accordingly, while the positive electrode plate 10 and the negative electrode plate 20 form a current collector, pores formed in the positive electrode plate 10 are filled with nickel hydroxide containing an electrically conductive material compound as an active material, and the pores formed in the negative electrode plate 20 The hydrogen storage alloy (MH Alloy) is filled.

Next, a separator 50 made of polypropylene (PP), which is a porous plate material having a thickness of several hundred μm to 2 mm, is inserted between the positive electrode plate 10 and the negative electrode plate 20 to form the electrode plate group. do.

Then, after stacking several positive electrode plates 10 and negative electrode plates 20 in accordance with a desired capacity (large capacity), the positive electrode plate 10 is connected to the positive electrode column 30, the negative electrode plate 20 to the negative electrode column 40 It is connected and wrapped around the outside with a polypropylene (PP) band (60) for mechanical fixation.

Finally, the electrode plate group consisting of the positive electrode plate 10, the negative electrode plate 20, the separator 50, and the like is seated on the precursor 70 made of synthetic resin (ABS), and a predetermined electrolyte solution (KOH + LiOH + Di) is injected. Next, the battery manufacturing is completed by fixing and sealing the cover of the roll 70 and performing electric activation.

Here, the separation membrane 50 prevents a short circuit due to contact between the pole plates and maintains the electrolyte injected into the precursor 70. The anode column 30 and the cathode column 40 are the anode plate 10 and the cathode plate. (20) is electrically connected to the positive / negative terminal of the precursor.

In the drawings, reference numerals denote nickel-plated terminals 30a and 40a and the breakdown voltage safety control unit 90.

In addition, the electrode plate group structure of the large-capacity nickel / hydrogen storage alloy secondary battery of the present invention is pressurized and supported by the polypropylene (PP) band 60 to finish the process of forming the electrode plate group, the positive electrode plate 10, The outside of the electrode plate group 100 including the negative electrode plate 20 and the separator 30 is wrapped by the shrinkage tube 80.

That is, the synthetic resin heat shrink tube 80, such as polyvinyl chloride (PVC), which is chemically stable to alkali, is cut according to the size of the electrode plate group, and heat is applied to cover the outer surface of the electrode plate group.

In the present invention, a polyvinyl chloride (PVC) heat shrink tube 80 is used as an embodiment, but other synthetic resins may be used as long as the material has durability (chemically stable) in alkali.

According to the present invention, the improved effect of the shrinkage tube wrapping on the electrode plate group of the nickel / hydrogen storage alloy secondary battery can be more clearly confirmed through a table showing the following test results.

[Table 1] Prevention of Pollution in the Rolling Mill

-Test cell: Pocket type nickel / hydrogen storage alloy secondary battery (Pocket Type Ni-MH 100Ah).

-Evaluation condition: The amount of the eluted active material attached to the inside of the tank was evaluated at a high temperature (60 ° C) for a long period of time (3 months) with a floating charge voltage.

-Results of evaluation: The amount of active material attached (100 mg) before improvement (before shrink tube wrapping) and the amount (5 mg) after improvement (after shrink tube wrapping).

As a result, by applying the shrinkage tube 80 to the outside of the electrode plate group, the eluted active material is hardly contained in the electrolyte, thereby preventing the electrolyte from directly reacting with the precursor, thereby significantly reducing the internal contamination of the precursor.

[Table 2] Improvement of discharge capacity at low temperature (-18 ℃)

-Test cell: Pocket type nickel / hydrogen storage alloy secondary battery (Pocket Type Ni-MH 100Ah).

-Evaluation condition: normal temperature charging (charged at 10A for 16 hours at 20 ℃)

            Low temperature (24 hours at -18 ℃)

            Low temperature discharge (Discharge up to 0.9V at 100A at -18 ° C).

-Evaluation result: 25 minutes before improvement (before shrink tube wrapping) and 40 minutes after improvement (after shrink tube wrapping).

As a result, when used at low temperatures, the shrinking tube 80 prevents the cold electrolyte from directly reacting with the electrode plate by keeping warm, thereby minimizing the decrease in low-temperature discharge capacity.

Thus, in the case of a pocket type, it is possible to use particularly an eco-friendly active material, is resistant to rapid charging and large current discharge, has a long service life (more than 2,500 times of charge and discharge), and has a wide temperature use range (-25 to 500 ° C.). A secondary battery resistant to humidity can be obtained.

In the above embodiment, the positive electrode plate 10 and the negative electrode plate 20 constituting the electrode plate group are implemented in a pocket type, but as another embodiment, the positive electrode plate 10 and the negative electrode plate 20 are generally known as paste types. Can be carried out.

For example, in the positive electrode plate 10, nickel hydroxide powder (Ni (OH) ₂ ) containing a cobalt compound as a conductive material is added to a nickel substrate on which a plurality of three-dimensional pores are formed, dried, and then molded (rolled). do.

In addition, the negative electrode plate 20 is mixed with a hydrogen hydride alloy (MH: Metal Hydride), a binder (Binder), a conductive material (conductor) and water in the form of a powder, kneaded, coated on the surface of the steel substrate and dried What is necessary is just to shape | mold (rolling).

Thus, when the paste type (Paste Type) is configured as compared to the pocket type (Pocket Type) it can be manufactured in a relatively light and short (輕薄 短小) type, easy to install or move, and can be applied to a variety of loads other than industrial.

In addition, the present invention is applied to a submerged cell in which a large amount of electrolyte is eluted from a starved cell and a flooded cell, which are two types of storage batteries, depending on the amount of electrolyte. More preferably.

The electrode plate group structure of the high-capacity nickel / hydrogen storage alloy secondary battery of the present invention configured as described above can prevent the contamination of the precursor to determine the height of the electrolyte from the outside and prevent the rapid increase of the internal resistance when used at low temperature, thereby reducing the discharge capacity. Minimizes useful effects

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various changes or modifications can be made within the spirit and scope of the present invention, and such modifications or variations are attached thereto. Belong to the claims.

Claims (3)

In the pole plate group structure of the nickel / hydrogen storage alloy secondary battery having a pole plate group consisting of a plurality of positive electrode plates connected to the positive electrode and a plurality of negative electrode plates connected to the negative electrode and a separator installed between the positive electrode and negative electrode plate, The pole plate group is wrapped by a shrink tube (Wrapping), the positive electrode plate and the negative electrode plate (Pocket) type or paste (Paste) characterized in that the pole plate group structure of a large capacity nickel / hydrogen storage alloy secondary battery. The method of claim 1, The secondary battery is a pole plate group structure of a large capacity nickel / hydrogen storage alloy secondary battery, characterized in that the flooded (Flooded) type. The method according to claim 1 or 2, The shrinkage tube is a plate structure of a large capacity nickel / hydrogen storage alloy secondary battery, characterized in that made of a chemically stable synthetic resin alkali.

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