JPS6313281A - Metal-hydrogen alkaline storage battery - Google Patents

Abstract

PURPOSE:To increase storage performance and cycle performance, and to retard capacity drop caused by powdering of a negative electrode and drying up of a separator of a metal-hydrogen alkaline storage battery by arranging a nega tive electrode using hydrogen storage alloy as main active material, a positive electrode, an alkaline electrolyte, a separator, and a compound having Si-O bond. CONSTITUTION:A hydrogen storage alloy of a negative active material such as LaNi5 is crushed in fine powder, and uniformly mixed with PTFE, and they are kneaded to obtain fibrous state. The mixture is formed in paste by adding water, and sticked on the side of a nickel plated punched metal current collector to obtain a negative electrode 1. Nickel hydroxide powder is kneaded with PTFE to form paste, and the paste is sticked to a nickel plated punched metal current collector to obtain a positive electrode. The positive electrode 3 and the negative electrode 1 are arranged so that a glass fiber 2 containing SiO2 is in contact with one side of hydrogen storage electrode of the negative electrode 1, and they are spirally wound with a separator 4 to obtain a spiral electrode. The spiral electrode is inserted into a metal can and alkaline electrolyte is poured, then the container is sealed.

Description

DETAILED DESCRIPTION OF THE INVENTION G) Industrial Application Field The present invention is directed to a metal-hydrogen-alkali storage cell (4) comprising a hydrogen-absorbing alloy as a main active material capable of absorbing and releasing water At. :Related.

(b) Conventional technology Storage batteries that have been commonly used in the past include alkaline replacement batteries such as μ-nickel-cadmium storage batteries, and lead-acid batteries, but in recent years, batteries with a larger amount of a, higher capacity, and higher energy than these batteries have been developed. There is a possibility that it will be 6 degrees. Friendly metal-hydrogen alkaline storage batteries, which have a negative electrode equipped with a hydrogen-absorbing R electric source made of a hydrogen-absorbing alloy, are attracting attention.

Hydrogen storage alloys used in the negative electrode of this type of battery include:
For example, as disclosed in Japanese Patent Publication No. Sho 59-49671, LaN1a and its improved Al three-element LaN
i4Co, LaNi4Cu and LaNi18F
・Alloys such as α2 are known. A porous body made by sintering these alloy powders together with conductive material powder is used as a hydrogen storage electrode (Japanese Patent Publication No. 59-49669), or a mixture of these hydrogen storage alloy powders and conductive material powder is used. [1ii1
Method of using hydrogen as a hydrogen storage electrode (% Kosho 57-302
Publication No. 73] etc. are adopted. Also, as a positive electrode,
Sintered nickel electrodes are used, such as those used in nickel-cadmium storage batteries.

However, this type of metal-hydrogen alkaline storage a has the problem that the negative electrode 1 is made of a hydrogen storage alloy; active hydrogen stored therein reacts with the positive electrode to cause self-discharge, resulting in poor storage characteristics.

Moreover, in addition to the above-mentioned problems when using S in the negative electrode, the hydrogen storage alloy in the negative electrode is used in the above-mentioned battery. Light discharge in the pond! :Therefore, the hydrogen t-aRL, which is the negative electrode active material, is released into the hydrogen t-aRL, and the single discharge cycle (:accompanied by the repetition of the above-mentioned occlusion and release; there is also the problem that the alloy lattice deforms and causes pulverization. However, since the pulverized hydrogen storage alloy falls off from the electrode, the electrode capacity decreases significantly during battery cycling, and the cycle characteristics deteriorate.

In addition to the aforementioned problem of poor storage characteristics of this type of battery, MJ has the following problems with regard to the positive electrode. When this type of storage battery is charged, hydrogen is generated from the negative electrode, creating a pressurized hydrogen atmosphere inside the battery can.

After the charged product of the positive electrode is reduced by hydrogen C, the metal oxide, which is the main active material of the positive electrode, can become a charged product of higher-order oxides, which is susceptible to light and cine emissions, and furthermore. This tendency becomes more noticeable as the number of cycles increases, leading to a decrease in battery capacity, which is a problem. On the next page, when the positive electrode is ≦2, the positive electrode whose main active material is a metal oxide expands as the number of cycles progresses and absorbs the electrolytic at. This causes dry-out of the separator, resulting in a low battery capacity. T
Problem 8A that the invention aims to solve is that the storage characteristics of a metal-hydrogen alkaline storage battery equipped with a negative electrode whose main active material is a hydrogen-absorbing alloy are significantly improved by 5: The main purpose of the present invention is to improve the cycle characteristics.In addition, the present invention aims to improve the cycle characteristics.
Separator part based on absorbing liquid C2) I knee! The purpose of this is to suppress the decrease in capacity due to

, group) Rounding means to solve the problem The eight BAs are a negative electrode and a positive electrode whose main active material is a hydrogen storage alloy, an alkaline electrolyte, and a separator.

There is a metal-hydrogen alkaline storage battery 4 characterized in that it is composed of a compound having a 5i-0 bond that dissolves in the alkaline electrolyte.

Incidentally, examples of the compound having a 5i-o bond include silicon dioxide, silicate, silanol, ethyl orthosilicate, methyl orthosilicate, and the like.

The form of the compound is silicon dioxide (S102)t
A glass fiber body containing ``3'' or liquid sodium silicate is suitable.

In addition, when a glass fiber body is used as a form of a compound having a 5t-O bond, it is sufficient to insert it between the positive and negative electrodes, and when used as a liquid or powder, C2 is added to the alkaline electrolyte. or in the active material paste during electrode manufacturing (=
Just mix it in.

(E) Action Alkaline solution C: A compound having a soluble Sl-〇 bond. A polymer compound forms on the surface of the positive and negative electrodes.

This polymer compound is a compound consisting of the basic structural unit of 8104, and has a three-dimensional network structure, and this f(OH), which is the discharge rod of the pond, can pass through this structure, but it is generated from the Since the oxygen gas is larger than 0ff-, it cannot pass through the structure.

It can suppress oxygen generation and acid diffusion from the positive electrode, which is the cause of storage *note deterioration or self-discharge.
Since OH-, which is a discharge species, can pass through C tin without any influence in the polymer compound, discharge characteristic C: For example, bad shadow! #It's not about giving money.

By arranging the glass fiber body containing csiozg in contact with the special negative electrode, the silicic acid produced by reaction with the alkaline electrolyte is adsorbed on the surface of the hydrogen storage alloy, which is the main active material of the negative electrode, and this is condensed. , becomes a polymer compound,
Partial C on the surface of the hydrogen storage alloy: Enoki C: By,
Alkaline electrolyte C: suppresses the decline in hydrogen storage capacity due to corrosion.

Since the binding force between particles is further improved by the polymer compound 4 produced by condensation, it is possible to suppress pulverization, shedding, and a decrease in the density of the negative electrode active material.

In particular, by arranging the glass fiber body containing 1::5 iOz so as to return the positive electrode C, the silicic acid produced by reacting with the alkaline electrolyte is absorbed onto the surface of the metal oxide, which is the main active material of the positive electrode. This is adsorbed and condenses to form a polymer compound that partially covers the surface of the metal oxide, suppressing the reduction caused by the pressurized hydrogen atmosphere inside the battery, and at the same time, the polymer compound suppresses the expansion of the positive electrode. , increase in liquid retention of the positive electrode77
0 can be suppressed and the dryer of the t pallet part)
t-suppression.

10,000, when using sodium silicate, the above-mentioned effects (: In addition, since sodium silicate is water-soluble,
Since it can be added without changing the battery structure, it is extremely advantageous in terms of the process.

Furthermore, if sodium silicate is added when paste is mixed, the entire negative electrode will be bound by the polymer compound, improving the strength of the negative electrode. Does the pre-e polymer compound cover the entire surface of the negative electrode due to penetration? Covering improves storage properties.

(F) Examples Example 1 96 parts by weight of LaN15i crushed and pulverized as a negative electrode active material, 6 mff of PTFE (fluororesin) powder
Add 1 part and mix uniformly to form PTF'Et-fiber.

A negative electrode is obtained by pasting a punched metal current collector on both sides of the punched metal current collector coated with water and coated with nickel. Similar (: PTF' to nickel hydroxide powder)
Et was added and kneaded once to form a paste, which was then ground onto a nickel-plated punched metal current collector to obtain a nickel positive electrode. In this way, the positive electrode (38 negative electrode (IJtg1) as shown in the figure, the glass fiber body (2) containing 5102 is placed on one side of the hydrogen storage electrode of the negative electrode (1), After winding together with a polypropylene separator (4) to obtain a spiral ta body, and inserting this electrode body into a battery outer can, an alkaline electrolyte was injected, and the seal was completely sealed to a nominal 8.
I used a 1200mAH battery for this purpose.

Example 2 As shown in FIG.
A non-exploding F!A battery (B)' was obtained in the same manner as in Example 1, except that a spiral electrode body was used in which the electrode body was connected to both sides of the negative electrode (1).

Example 3 As shown in FIG. 3, a glass fiber body (2) containing 5iO22
A battery 0 of the present invention was obtained in the same manner as in Example 1, except that a spiral electrode body was used in which the positive electrode (3) was placed on one side and the other was placed on one side.

Example 4 As shown in FIG.
2) was the same as in Example 1 except that a spiral electrode body in contact with both surfaces of the positive electrode (3) was used to obtain the present invention battery 〇 Example 5 The above-mentioned Example 1 and A negative electrode paste obtained in the same manner (1Offijt% of sodium silicate (water glass) was added, and after crosstalk, a negative electrode was obtained. This negative electrode was used in the same manner as in Example 1, except that a fibrous body containing -810zi was not used. The battery of the present invention (■) was tabulated.

Example 6 The present invention 1, which is similar to Example 1, was prepared using the above-mentioned Example 1. !Pond Dke was created.

Comparative Example A comparative battery was prepared in the same manner as in Example 1, except that the glass fiber body containing Si02 was not used as shown in FIG.

These four inventors of the present invention, (Hitoshi, 0. (DJ, (c)
, (0 and comparison battery (b) i12QmA for 16 hours.

Then 240 mAr'i! The batteries were discharged until the am pressure reached 10VI:q, and the cycle characteristics were compared. The result is the 6th
As shown in the figure.

Next, the seventh factor C2, the relationship between the number of days the battery is left after photovoltaic charging and the remaining battery capacity, is shown as a deep characteristic comparison diagram. In terms of storage properties, the battery of the present invention^, (Bc).

@, @, (F) is a comparative battery O) (: The ratio has been significantly improved. This is a polymer made by condensation of silicic acid produced when an alkaline electric folding liquid is 2ft!4 dissolved. Compound #-1:
5IO4t-Basic basic unit with three-dimensional mesh structure t,
Since the oxygen generated from the positive electrode and the oxygen that diffuses do not pass through this mesh structure, they react with the active hydrogen of the negative electrode and are not consumed, which is thought to improve the storage customization.

As is clear from Figure 6, CIIQ, (Q, RiJ, (c), D has better cycle characteristics than comparative battery q. csi-
It is thought that this is because a compound having a 0 bond reacts with an alkaline electrolyte to produce silicic acid, which condenses to produce a polymer compound. After the cycle test, the present invention incorporated a glass fiber body containing S i O22.

0.0. A comparative battery using no fibrous body was disassembled and examined.

Special C: Negative electrode 1: Comparative battery O] did not incorporate a glass fiber body containing 8102, so the hydrogen storage alloy was significantly pulverized, and analysis revealed that LaN1a
decreased, and a large amount of La(OH)3, which was thought to have been generated due to the influence of the alkaline electrolyte, was formed.
2 vs. 1 Invention 4 (The negative electrode of P9 is made back with the glass fiber body containing 5iOz2, so the progress of pulverization of the hydrogen storage alloy is slow and the amount of mu(OH)s produced is small. - 10,000, Insert When the glass fiber body was observed, it was found that the glass fiber body became thinner.
When considering the distribution of 2 EPMA analysis, @9 Figure C;
As shown, the main 1:sl is distributed on the surface of the negative electrode, and is thought to hold the negative electrode active material and at the same time suppress the diffusion and intrusion of oxygen gas.

By placing the 1PrC glass fiber body in contact with the negative electrode, the glass fiber body dissolves in the alkali solution, producing silicic acid, which condenses to produce a polymer compound, which causes the surface of the hydrogen storage alloy negative electrode to dissolve. In addition to suppressing the decrease in hydrogen storage capacity due to corrosion, the hydrogen storage alloy particles are strongly bound and retained by the polymer compound C.
Micronization of negative electrode.

This is thought to have suppressed shedding and capacity reduction.

In particular, batteries 0 and 0 of the present invention in which the glass fiber body was disposed between the positive electrode and the return port were compared with comparative battery 0.

As can be seen from FIG. 6, the initial capacity is large. Since the capacity t of this type of metal-hydrogen alkali storage to is dominated by the positive electrode, it is thought that the initial capacity increased because the positive electrode capacity increased. Regarding initial capacity (Di > (C) >
(The relationship between Q does not change as the number of cycles progresses, and the relationship between
The entire history of the higher-order oxide Ni0OH, which is a photoelectric product, is shown here. Since this Ni00H is a high-order oxide,
It is unstable and easily becomes 1:N1 when placed in a sword-pressure hydrogen atmosphere.
It changes to (OH)2 and becomes a discharge product. Battery of the present invention 0.
(The glass fiber body containing qpo5loz is arranged so as to be in contact with the positive electrode, and it reacts with the alkaline electrolyte to generate silicon yield, which condenses to form a polymer compound that partially removes the positive electrode active material (: 4, the reaction between the photoelectric product N100H and the pressurized hydrogen in the tank is extended, and N1(OH
) It is thought that the amount of zt two-transition elements decreased, the photoelectric efficiency improved, and the battery capacity increased accordingly. Also 5ot
When the battery was disassembled, the positive electrode of comparative battery 0 expanded and contained a large amount of electrolyte. was small and contained a moderate amount of electrolyte.

In addition, in the examples, LaNi was used as a hydrogen storage alloy in the negative electrode.
s, a nickel electrode is shown as a positive electrode, but it is not limited to these in any way, and hydrogen storage alloys such as T1-Ni alloy, Tl
- It is flexible to use a Mn-based alloy and a silver oxide 1X electrode as the positive electrode.

(G) Effect of the invention Negative electrode made of hydrogen storage alloy? Preparation 4 - Hydrogen alkaline storage in a pond (: 5i-0 that can be dissolved in alkaline electrolyte)
Compound 1 with bond: t# electromotive same circle C pairing C
From the second point, it is possible to improve the storage characteristics, completely suppress the decrease in the KL pond capacity, and obtain an excellent metal-hydrogen alkaline storage battery.
When a glass fiber body containing iOzt is placed, the falling off and corrosion of the hydrogen storage alloy is suppressed, and when a glass fiber body containing 5iOz=2 is placed to be convenient for use with the positive electrode, Tickle's custom-made improvement sink is placed. In addition! The initial capacity of the pond is significantly increased! −
The south improves. Furthermore, when sodium silicate is used, it can be added without changing the battery structure in any way and the above effects can be obtained, so its industrial value is extremely large.

[Brief explanation of the drawing]

Fig. M1 rj SI 02 'f: Fig. S of the spiral electrode body of the present invention battery (8) in which the glass fiber body containing the glass fiber body is in contact with only one side of the negative electrode. Figure 3 is a diagram of the spiral electrode body of the present invention'Ha(C) in which the glass fiber body containing 5iOzi is in contact with only one side of the positive electrode.
FIG. 4 is a diagram of a spiral electrode body of cell 0 according to the present invention in which a glass fiber body containing all SiO+ is in contact with both surfaces of the positive electrode, and FIG. 5 is a diagram of a spiral electrode body of comparative cell q. Figure 6 is a cycle comparison diagram, Figure 7 is a preservation custom comparison diagram, Figure 248 is an EMPA analysis diagram of St of comparative battery q negative electrode,
Figure 9 is an EMF'A analysis diagram of Sl of the present invention's battery (equalized negative electrode).
-Glass fiber body containing 5102, (3)...to the positive electrode to the Kkel electrode (4)...separator. Prisoner, Jine (CJ, (DJ, ■, 0...Battery of the present invention 0)
・・・Comparison battery

Claims (6)

[Claims] (1) A negative electrode whose main active material is a hydrogen storage alloy, and a positive electrode,
A metal-hydrogen alkaline storage battery comprising an alkaline electrolyte, a separator, and a compound having an Si-O bond that can be dissolved in the alkaline electrolyte. (2) The metal-hydrogen alkaline storage battery according to claim (1), characterized in that silicon dioxide or sodium silicate is used as the compound that can be dissolved in the alkaline electrolyte. (3) The metal-hydrogen alkaline storage battery according to claim (2), wherein the glass fiber body containing silicon dioxide is arranged so as to be in contact with a negative electrode. (4) The metal-hydrogen alkaline storage battery according to claim (2), wherein the glass fiber body containing silicon dioxide is arranged so as to be in contact with a positive electrode. (5) The metal-hydrogen alkaline storage battery according to claim (2), wherein the sodium silicate is added to the alkaline electrolyte. (6) The metal-hydrogen alkaline storage battery according to claim (2), wherein the sodium silicate is added to a negative electrode whose main active material is the hydrogen storage alloy.