JPS5990358A - Positive plate for alkaline battery - Google Patents

Abstract

PURPOSE:To obtain the positive plate having excellent discharge characteristic by filling a porous material made of nickel formed like sponge with the active substance powder pasted with a mixed liquid of an organic solvent and water. CONSTITUTION:A porous material made of nickel formed like sponge having the structure which is continuous in three-dimensional is filled with active substance powder paste mainly consisting of nickel hydrate and conductive material which has been pasted using a single material or mixture of organic solvents such as ethylene glycol, polypropylene glycol or triethylene glycol, etc. For example, the mixed powder of nickel hydrate of 85 part and nickel powder of 15 part is pasted through addition of mixed solution of polypropylene and water, the porous material made of nickel formed like sponge having the structure which is continuous in three-diensional with average pore diameter of 0.3mm., porosity of 95% and thickness of 1.2mm. is filled with said pasted mixed powder. It is then dried under 100 deg.C, such porous material is then impregnated with dispersion liquid of fluorine resin. The material is further dried under 80 deg.C for an hour and then pressed with a pressure of 500kg/cm<2>. Thereby, a positive plate can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positive electrode plate for alkaline batteries in which a paste-like active material is filled into sponge-like nickel porous holes, and when the active material powder is mixed into a paste. Organic solvents such as T ethylene glycol, propylene glycol, or 1
The purpose is to produce 1 q of hollow positive electrode plates by using 1 ml of lyethylene glycol (dissolved in a mixture of water, water, etc.).

Conventionally, a sintered body of nickel powder has been used as the positive electrode plate substrate for alkaline batteries, but its porosity is 70.
・～・8096 culm m, and if the porosity is increased beyond this, the mechanical strength will be significantly reduced. ,
There were drawbacks such as cracking and peeling of the active material. [When filling the active material, a method called vacuum impregnation method is usually used.After the substrate is impregnated under reduced pressure with an aqueous solution of a salt such as 1v1 nickel acid or sulfuric acid, it is treated with an alkaline aqueous solution. The method used is to repeat the process of roughly washing in hot water and drying. However, the amount of i73 filled by the - times of operations is small, and moreover, the amount of m(-1) filled from the second time gradually decreases, so it is usually necessary to repeat the operations 4-10 times. The drawback is that the manufacturing process is complicated and the cost is high.

On the other hand, using an organic solvent such as ethylene glycol or propylene glycol and a dispersion of a fluororesin, paste the compound into nickel hydroxide and Cla7-I-1-1.
After oxidation, 121 supports of nickel l1i1 etc. were coated with
The method has been proposed, but this method has a simple manufacturing process, but on the other hand,
It is known that there is a problem with the lifespan due to the lack of strong polishing of the electrode plates.

In recent years, Pace 1 ~
Directly filling and covering a single type of active material in a shape is attracting attention.

Sponge-like nickel porous material with a three-dimensionally continuous 1M structure (the porosity of each layer is as high as 90% to 111%, but the mechanical strength of the material is high. Moreover, the pores are large. It is possible to increase the capacity of the positive electrode plate by filling the active material into the porous material, but filling is simpler and allows for a continuous process, which is also economically advantageous. From 1, if only water is used as a mixing solution when forming the active material into paste 1, the viscosity of water is low, so it is not possible to fully fill the Nirakur porous body with paste 1. It has been proposed that water-soluble polymers such as carboxymesalcel [l-su] as a binder be dissolved in water to increase C viscosity. If the active material is present, the amount of active material will decrease, and the polymer will be decomposed by the oxygen photogenerated from the positive electrode (J, -), producing carbonic acid and reducing the conductivity of the electrolyte. /L ability decreases
There was a drawback that the lifespan of the stiffness was shortened. In addition, (if water is present when drying the board, the surface of the porous material or conductive material will be oxidized and the electrical resistance will increase, so it is sufficient <'t)
! There was also the drawback that the performance of the board was not perfect.

Therefore, it is possible to use a highly viscous organic solvent as a mixing solution, but since it has a high boiling point and requires a high temperature and long time for drying, the activity of the active material decreases during drying. There is also a drawback.

The present invention shows that when an organic solvent such as polyethylene glycol, propylene glycol, or a mixture of polyethylene glycol, polypropylene glycol, water, etc. is used to form active material powder into a paste, the discharge performance of the electrode plate can be improved. This is based on the discovery that there is a significant improvement in

Examples of the present invention and their effects will be described below in detail.

The positive electrode plate used in the present invention was manufactured as follows.

First, a mixed solution of propylene glycol and water is added to a mixed powder of 85 parts of Tsunonol hydroxide and 1 j) parts of nickel powder to form a paste. ') Giniko's pace] ~ with an average pore diameter of 0,3111+11. A three-dimensionally continuous structure of 1095% porosity + 1.2mm thickness was filled into a sponge-like porous nickel material, dried at 100°C, impregnated with a fluororesin dispersion, and further dried at 80°C for 1 hour. 50 years old after drying! ]//CIl? A positive electrode plate according to the present invention was obtained by applying a pressure of C-. Then, what about this one positive electrode plate]! Two sintered cadmium negative electrode plates as i, and electric II
S, G, 1,250 (20℃) K O as Jv liquid
A graded type battery according to the present invention with a nominal capacity of ■1,0△11 was manufactured using a +-1 aqueous solution, and a 0.1 CA
After charging for 16 hours, the active material utilization rate was determined by discharging to OV against the mercury oxide electrode at i, o(''; Δ. Here, the mixing ratio of propylene glycol and water was varied. Figure 1 shows the changes in the time required to dry and cover the electrode plate after filling from Pace 1 to Pace 1.Furthermore, Figure 2 shows the changes in the active material utilization rate during that period. 'ji' 2
From the figure, it can be seen that the active material utilization rate is good when the propylene glycol content is in the range of 10 h-90%. Also, even if ethylene glycol 1 to lyethylene glycol 1- etc. are used instead of propylene glycol,
It was confirmed that similar results could be obtained.

Next, add 50% propylene glycol and water using a mixing solution.
One positive electrode plate according to the present invention manufactured using a mixture of the two and one conventionally known Par 21~ type cadmium negative electrode plate were wound in a spiral shape through a separator made of Norilon nonwoven fabric, and the electrolyte was mixed with the electrolyte. 8. A sealed nickel/7J domium battery (A) according to the present invention having a nominal capacity of 2.4Δh was fabricated using a potassium hydroxide aqueous solution (20° C.). For comparison, batteries (B) and (C) were manufactured using a conventional method using a positive electrode plate containing only a 0.6 w 1% carboxymedylrel+1-su aqueous solution and propylene glycol as a paste. These batteries are 2
0℃, 0, I CA F After charging for 16ffJ, 0
．． 1 with 2OA. Figure 3 shows the discharge f nol when discharged to Ov. From the figure, 6-Battery according to the present invention (△) is J, battery according to the conventional method (B) and (C). It can be seen that it is markedly (1).

I'm not sure why using a mixture of a solvent and water when converting a living substance δT from Pace 1 to 1 causes a marked change in the direction of use, but the following For the following reasons, J and Rumodo'A are considered. In other words, carboxymedyl cell [1
When the active material is made into paste 1 using an aqueous solution of a binding agent such as J, the internal resistance is thought to increase because the electrode plate contains the binding agent of insulation 1. . 21k,
Base 1 - When drying the electrode plate that has been fully charged,
ii) It is considered that a part of the surface of the skeleton of the electric abrasive particle IN+porous body is oxidized, and the electrical resistance becomes lower than Z. It is conceivable that the internal resistance of the entire electrode plate would increase and the 11 station performance would deteriorate. Furthermore, if only a solvent is used, it is thought that the drying takes a long time, which lowers the activity of the active material and deteriorates the discharge performance.However, according to the present invention, , the electrode plate contains an insulating substance.
It is thought that the surface of the conductive material, etc., is unlikely to be oxidized. Further, since the drying time is short, it is considered that the activity of the active material is extremely unlikely to decrease by 1 degree. This is considered to be the reason why the discharge performance is significantly improved compared to the conventional positive electrode plate.

As described above, according to the present invention, by using a mixture of an organic solvent and water as a mixing solution when making an active material into a paste, the electrical properties of a positive electrode plate can be significantly improved.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams showing the relationship between propylene glycol content, drying time, and active material utilization rate, respectively; This is a comparison diagram of the IC and charging characteristics of batteries (B) and (C) made by conventional methods. 3
Table of Contents Capacity (Ah)

Claims (1)

[Scope of Claims] 1. Active material powder containing nickel hydroxide and conductive material 44 is mixed with an organic solvent, for example] -] ethylene glycol 1-propylene It is characterized by filling a sponge-like Ninonol porous material with a dimensionally continuous structure using a base-like solution of a mixed solution of 1-L and water.
Positive electrode plate for alkaline batteries. 2. Claim 1J, wherein the content of the organic (a) medium in the above-mentioned mixed solution of solvent, water, etc. is 10 to 90%.
Positive electrode plate for alkaline batteries described in rJ.