JPS61271756A - Manufacture of electrolyte for colloid storage battery - Google Patents

Abstract

PURPOSE:To obtain a storage battery with strikingly excellent performance by dealkali-treating the alkaline aqueous solution of a silicon oxide and adding dilute sulfuric acid to make a gel. CONSTITUTION:1-9wt% alkaline aqueous solution of a silicon oxide is dealkali- treated, and dilute sulfuric acid is added to a silicic acid monomer aqueous solution thus obtained to make a gel. It is necessary that SiO2 density in the aqueous solution of a starting material is over 1wt% as a lower limit density of the starting material since the gel strength which is formed is deficient if the silicic acid density in the silicic acid monomer aqueous solution obtained is too low. And it is preferable that the SiO2 density in the aqueous solution of a starting material is 9wt% as an upper limit of density of the starting material because the silicic acid monomer aqueous solution is quickly solidified during the dealkali-treatment or after the treatment if the SiO2 density is too high. According to this method, by-production of unfavorite substance is lower even if the gel is formed, and it is possible to extremely increase the performance of the storage battery in comparison with the conventional method.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrolyte for colloidal storage batteries,
More specifically, the present invention relates to an electrolyte for colloidal storage batteries that has low fluidity and is easy to handle.

[Conventional technology]

Conventionally, lead-acid batteries have been widely used as storage batteries because of their stable performance such as capacity and high-rate discharge characteristics, and their low cost.

However, lead-acid batteries must contain a large amount of highly fluid dilute sulfuric acid as an electrolyte, so care must be taken when handling the battery itself, which contains highly reactive dilute sulfuric acid. There must be. In addition, during use, discharging and charging are repeated, but if an overcharge occurs during charging, the current flowing through the battery at that time electrolyzes water and generates oxygen and hydrogen, which is undesirable. This phenomenon occurs and the electrolyte decreases, so you must always be careful to check the amount of electrolyte and replenish water.

In order to eliminate the drawbacks caused by the fluid electrolyte of lead-acid batteries, so-called colloidal batteries have been developed. This colloidal storage battery is made by mixing the dilute sulfuric acid of lead-acid batteries with water glass or sulfuric acid sol to form a gel, or by dispersing dry fine silica powder in dilute sulfuric acid and gelling it. It has no liquidity.

In a colloidal storage battery using such a gelled electrolyte, most of the electrolyte is fixed within the battery. In addition, there are numerous cracks in the generated gel, and these cracks form gas passages between the ■ electrode and the O electrode. Therefore, for example, at the end of charging, oxygen gas generated at the electrode (1) passes through the cracks in the gel and reaches the e-electrode, where the e-electrode is discharged according to the following reaction formula, and water is produced. Therefore, the decrease in water in the electrolyte is suppressed.

As described above, colloidal storage batteries have the advantage that they are easier to handle and reduce the amount of water lost compared to lead-acid batteries that use a fluid electrolyte. However, colloidal storage batteries also have the following drawbacks: (1) The gel-like electrolyte tends to stabilize by shrinking over time, and the so-called syneresis occurs, which separates the dilute sulfuric acid held inside. syneresis).

(No) Compared to a lead-acid battery that uses a fluid electrolyte, the chargeable and dischargeable electric capacity is very small even if the amount of active material in the electrode plate is the same.

(3) Compared to conventional lead-acid batteries having the same amount of active material and plate area, colloidal batteries have a large drop in high-rate discharge characteristics.

(4) Severe vibrations and shocks cause the gel to break down and the electrolyte to become fluid.

[Problems to be Solved by the Invention] The present invention eliminates the above-mentioned drawbacks of conventional colloidal batteries, and is easy and safe to handle, reduces water loss, and eliminates electrolyte separation. It is an object of the present invention to provide a novel electrolyte for colloidal storage batteries which has low generation of plasma and fluidization, high electric capacity, and high rate discharge characteristics that can be used for starting automobile engines.

[Means for solving problems]

According to the present invention, the above problem can be solved by dealkalizing a 1 to 9% by weight alkaline aqueous solution of silicic acid oxide, and adding dilute sulfuric acid and, if desired, an improver and a binder to the thus obtained aqueous silicic acid monomer solution. The problem is solved by a method for producing an electrolyte for a colloidal storage battery, which is characterized in that the electrolyte is added to form a cotetraid.

A colloidal storage battery basically consists of positive and negative electrode plates, a seven-palate plate to prevent contact between these electrode plates, and a non-flowable electrolyte with ionic conductivity.

Gelation is carried out by the following method tζ: (a) mixing a water glass (Na20 Disperse silicic anhydride having a diameter of about 100 ml in dilute sulfuric acid.

When gels prepared by these methods are used as electrolytes, the disadvantages mentioned above arise.
The reason may be as follows.

When water glass is directly mixed with dilute sulfuric acid using the conventional method (a), since a large amount of Na ions are present, a large amount of sodium sulfate is inevitably produced as a by-product, which adversely affects the performance and life of the storage battery. In addition, in the method (b) using a silicon oxide colloidal sol, the colloidal particle size at the start is too coarse, and the additives used to make the sol stable have an adverse effect on the performance and life of the storage battery. lastly,
According to method (c), in which anhydrous sulfuric acid powder at the level of colloidal particles is dispersed in dilute sulfuric acid, no by-products are produced, but the colloidal particle size at the start is too coarse, which deteriorates the performance of the storage battery.

On the other hand, as a result of research by the present inventor, it was found that a solution of sulfuric acid monomer was prepared and mixed with dilute sulfuric acid. It has been found that the gel thus formed has excellent properties as an electrolyte for colloidal storage batteries.

That is, according to the present invention, a stable alkaline aqueous solution of silica folate, such as water glass, sodium silicate, potassium silicate, or silicic anhydride powder made water-soluble with an alkali, is used as a starting material. Instead of directly mixing this with dilute sulfuric acid, the alkali metal ions in the raw material aqueous solution are removed by means such as ion exchange, dialysis, and electrodialysis (dealalkalization treatment) to create an aqueous solution containing only silicic acid. The electrolyte is produced by colloidizing the

In the alkaline aqueous solution of silicon oxide, which is the starting material, in addition to monomeric silicic acid, multimeric forms such as dimers and trimers are present, and these are alkaline. Although stabilized by metal ions, when this solution is dealkalized, all silicic acid forms an aqueous solution in the form of unstable monomers. In the present invention, this aqueous solution of monomeric sulfuric acid is referred to as a silicic acid monomer aqueous solution.

According to this method, even if a gel is formed, there are few undesirable by-products, and the performance of the storage battery can be greatly increased compared to colloidal storage batteries made by conventional methods.

As for the lower limit concentration of the starting material, if the silicic acid concentration in the resulting silicic acid monomer aqueous solution is too low, the strength of the gel formed will be insufficient, so the SiO2 concentration in the starting material aqueous solution must be 1% by weight or more. It is. In addition, the upper limit of the starting material concentration is that if the SiO2 concentration is too high, the dealkalization will solidify in the ring or quickly after treatment, so the SiO□ concentration in the starting material aqueous solution should be 9'IL amount %. is desirable.

In other words, it is characterized by dealkalizing an alkaline aqueous solution of silicic acid containing 1 to 996 Sin in concentration to form an aqueous silicic acid monomer solution, which is then mixed with dilute sulfuric acid to form a gel. .

Further, in the electrolyte according to the present invention, aluminum, magnesium, barium, zirconium, germanium, niobium, vanadium, titanium, aluminum, and phosphorus may be used alone or in combination with 2M1 or more in the form of metal ions or oxides of these metals. It has been found that adding 0.01% to 0.596% of sulfide to the electrolyte in the form of fine powder prevents gel shrinkage, prevents separation, and reduces water loss. These metals also provide a good influence on the high rate discharge characteristics necessary for starting automobile engines, although this is not obvious.

At this time, when mixing fine powders such as oxides and sulfides of the metals into the electrolyte, a surfactant such as sodium lauryl sulfate (C, □H250503Na) is added to the electrolyte in order to facilitate dispersion. 0.00196-0.
It may be added in an amount of about 5%. However, if it is added in the form of metal ions, there is no need for a surfactant, and some oxide/sulfide powders have excellent dispersibility, so the addition of a surfactant is not an essential condition.

In addition, silicic acid powder, kaolin (H
, At2S 120B・H,O), Theolite (Nki2
0At203 (SiOρ work・(H2O), aluminum silicate (At (Ats 1Os)) 〇-magnesium silicate (Mg, SiO,), m-magnesium sulfate (Mg
One or two of Si02) and diatomaceous earth powder
0.596 to 0.596 by weight for the electrolyte in combination of species or more
Adding 5% increases the gel strength and makes it difficult for the gel to break.

The present invention will be explained in more detail with reference to the following examples.

Example 1 Potassium tetrasilicate hydrate (K2Si040g・H2O)
Dissolve 220g in distilled water to make a total amount of 3000g,
This is H-type strong acidic ion exchange resin Ampartite IR.
-1208St to prepare a silicic acid monomer solution. The ion exchange operation was carried out using an ion exchange resin that had been suction filtered to remove as much water as possible, and was carried out in a batch method by mixing it with an aqueous potassium tetrasilicate solution in a beaker.

SiO contained in the silicic acid monomer solution obtained after rotation
□Amount analysis revealed that it was 4.94%. Separately 959
A sulfuric acid mixture of 4.13 kg of concentrated sulfuric acid and 87 kg of distilled water was water-cooled and stirred, and 2 kg of a silicic acid monomer solution was slowly added thereto to prepare an electrolyte.

When the mixing of the liquids was completed, gelation did not start again and the liquid was in a very fluid state. Add this mixture to N70Z
When a ready-made storage battery with a dry interior was filled to the top of the electrode plates and left overnight, the electrolyte turned into a gel. This was charged in the usual way.

The storage battery obtained in this way was discharged at a constant current of 1t2A, and I
Q. JIS D for measuring discharge duration up to 5V
The capacity was measured by the method specified in 5301 (Storage Batteries for Automobiles) and found to be +19 Ah. Next, in order to measure the high rate discharge characteristics specified in the same method (JIS D 5301), after the storage battery was fully charged, it was left in a freezer with an internal temperature of -15°0 for 70 hours, and then a constant 600A We conducted a current discharge and measured the discharge duration until the terminal voltage reached 6V and the voltage at the 5th and 600th seconds after the start of discharge.The results showed that the discharge duration was 263 seconds, the voltage at the 5th second was ρaov, and the voltage at the 13th second was 975V. Met.

Example 2 JIS No. 1 water glass was diluted with distilled water so that the SiO2 concentration was 5% by weight, and the LOOG was passed through a column filled with H-type strongly acidic ion exchange resin Amberlite IR-120B and mixed with a silicic acid monomer solution. did.

Hereinafter, this will be referred to as liquid A for convenience. The SiO□ concentration in Solution A was 49,296. Separately 9596H2So, 4.
IS kg.

Prepare a solution consisting of 87 kg of water, 10 g of aluminum acid, 20 g of zirconium chloride, 5 g of sodium lauryl sulfate, and 2 g of silicone oil as an antifoaming agent. This is called liquid B. While cooling and stirring Solution B with water, 2 kg of Solution A was slowly added thereto to form an electrolyte. At the time when the mixing of liquids A and B was completed, gelation had not yet started and the mixture was in a very fluid state. Fill this mixed solution into a ready-to-use storage battery of N70Z size, which is dry inside, up to the top of the electrode plate, and -
When I left it for the night, the electrolyte turned into a gel. This was charged in the usual way.

When this storage battery was discharged at the same constant current of <11.2 A as in Example 1 and the capacity was measured, it was 6 t and 5 Ah.

Next, after fully charging this storage battery, the temperature inside the refrigerator will be -15
Leave it in the freezer at °0 for 70 hours and the terminal voltage will be 600A.
When discharged until v, the discharge duration was 265
Seconds, 5th second voltage is 9.90V, 500th second voltage is 9.85
It was V.

Example 3 About 2 to 150 g of S i 02 powder (about 100 meshes)
t of distilled water was added, stirred with a stirrer, and 251) g of KOH was added to disperse SiO□. The mixture was heated while stirring to completely dissolve the SiO□, and then distilled water was added to bring the total amount to 6000 g. After cooling, the mixture was passed through a column filled with Hfi (strongly acidic ion exchange resin Amberly) IR-120B to obtain a silicic acid monomer aqueous solution. Kaolin (HlAl, S
100 g of powder of OH・H2O) was added and dispersed. This is called liquid C. Separately, 95% concentrated sulfuric acid & 88 kg,
A mixture of 462 kg of distilled water, 15 g of zirconium oxide, 100 g of an aqueous solution of titanium oxide 6096, 5 g of sodium lacryl sulfate, and 2 g of silicone oil as an antifoaming agent is prepared in advance. This is called liquid D. Solution D was cooled with water, and while stirring, solution C was added slowly for a few seconds to form an electrolyte. At the end of the mixing, gelation had not yet started and the mixture was in a very fluid state. Fill this mixed solution into a ready-to-use storage battery of N70Z size, which is dry inside, up to the top of the electrode plate, and -
When I left it for the night, the electrolyte turned into a gel. This was charged in the usual way.

This storage battery was discharged at the same constant current of <11.2A as in Example 1, and the capacity was measured.
When left in a freezer at °0 for 70 hours and left at 600A until the terminal voltage reached 6V, the discharge duration was 25
The voltage at 0 seconds and 5 seconds is 9.75V, and what is the voltage at 1 second? , 7
It was 0V.

Comparative Example In order to compare the storage battery according to the present invention with a colloidal storage battery made by the conventional technology and to clarify the effects of the present invention, a colloidal storage battery was manufactured using silicon oxide colloidal sol and 60 automobile engines were started. Since there are no commercially available colloidal batteries with such high rate discharge characteristics, the same N70Z ready-to-use batteries as described in the examples were used.

The silicon oxide coroitosil used had a silicon oxide content of 2.
0%, and the colloid particle size was about zooooX.

First, 415 kg of 9596111 sulfuric acid and 547 kg of distilled water.
A dilute sulfuric acid mixed with 500 g of colloidal sol was prepared, and 500 g of colloidal sol was slowly added to the mixture while cooling with water and stirring to obtain an electrolyte. At the end of the mixing, the mixture had not yet gelled and was in a very fluid state. When this mixed solution was filled into an N70Z-sized ready-made storage battery with a dry interior up to the top of the electrode plates and left overnight, the viscosity increased and gelation began. However, it had chicken-tropic properties that made it easily fluidized by vibration or impact. This was charged under normal conditions.

This storage battery was discharged at a constant current of 11.2 A in the same manner as in Example 1, and the capacity was measured, and the result was a capacity of 49.5 Ah. Next, after fully charging this storage battery, it was left in a freezer with an internal temperature of -15°0 for 70 hours, and discharged at a constant current of 600A until the terminal voltage reached 6V.The high rate discharge characteristics were measured. Duration: 95 seconds, voltage at 5th second: &80V.

The voltage at the 600th second was 8.45V.

The results of this comparative example and the results of Examples 1 to 3 described above are summarized in the following table.

From the table above, it can be seen that the storage battery according to the present invention is superior to the storage battery using colloidal sol according to the prior art in any performance I/.

Regarding syneresis from the gel, slight syneresis was observed with the electrolyte of Example 1 according to the present invention, but the syneresis of the prior art was not as pronounced as that using Idosol.

In order to compare the fracture strength of the gels, the electrolytes prepared in Examples 1 to 1 and the electrolytes obtained by mixing the colloidal sol with dilute sulfuric acid were each immediately filled in 200 mt into a 500 mt beaker and gelled. Four beakers containing these gels were fixed to a sheet of plywood and subjected to reciprocating vibration to compare the gel strengths. As a result, the gel using colloidal sol, the gel of Example 1, and the gel of Example 2 were fluidized almost simultaneously, but the gel of Example 6 was not destroyed until the vibration was further increased.

Next, after these batteries were completely charged, a current of 1.5 A was applied to overcharge them, and the weight loss was measured to compare the amount of water lost.

The results are shown in Figure 1. The vertical axis of the graph in FIG. 1 shows the amount of weight reduction, and the horizontal axis shows the amount of overcharged electricity. Here, the symbols ■, ■, and ■ in the figure correspond to actual examples 1, 2, and 5, respectively, and ■ corresponds to a comparative example manufactured using colloidal sol.

As can be seen from this figure, the amount of weight loss is smaller in the storage batteries using the electrolyte according to the present invention, especially in the storage batteries using the electrolytes of Examples 2 and 3. In other words, it is thought that the amount of moisture loss is also small.

〔Effect of the invention〕

As described above, according to the present invention, a storage battery with significantly superior performance than conventional cotetraid storage batteries can be obtained, and syneresis of the electrolyte is eliminated by adding metal ions, oxides, or sulfides. The amount of moisture loss is small, and the high rate discharge characteristics are also improved.Additionally, by adding silicate powder, the gel strength increases and fluidization becomes less likely to occur.

[Brief explanation of the drawing]

The figure is a graph showing the change in the amount of decrease in the storage battery in when the storage battery is overcharged. (6 others)

Claims (1)

[Claims] 1. For a colloidal storage battery, characterized in that a 1 to 9% by weight alkaline aqueous solution of silicon oxide is dealkalized, and dilute sulfuric acid is added to the thus obtained aqueous silicic acid monomer solution to gel it. Method of manufacturing electrolyte. 2. Production of an electrolyte for a colloidal storage battery, which is characterized by dealkalizing a 1 to 9% by weight alkaline aqueous solution of silicon oxide, and adding dilute sulfuric acid and an improver to the thus obtained aqueous silicic acid monomer solution to gel it. Method. 3. For colloidal storage batteries characterized by dealkalizing a 1 to 9% by weight alkaline aqueous solution of silicon oxide, and adding dilute sulfuric acid, an improver, and a binder to the thus obtained aqueous silicic acid monomer solution to form a gel. Method of manufacturing electrolyte.