JPH11121008A - Negative electrode plate for lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the lowering of the life performance of a negative electrode plate under a high temperature by adding bisphenols and sulfite or amino acid formaldehyde condensate to an active material. SOLUTION: The polymer average molecular weight of bisphenols and sulfite or amino acid formaldehyde condensate added to an active material is preferably 0.3-3.0×10<4> . This condensate is preferably added along with a derivative of naphthalene sulfonic acid formaldehyde condensate. The condensate is preferably added along with lignin or its derivative. More practically, this condensate is a condensate of bisphenol A, sodium sulfite and formaldehyde. This constitution improves the life performance especially under a high temperature so that it can be applied to various kinds of lead-acid batteries and used for various kinds of utilizations.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a negative electrode plate for a lead storage battery.

[0002]

2. Description of the Related Art Lead-acid batteries are used in many applications from small-capacity consumers to large-capacity stationary ones, such as for starting and lighting vehicles. In recent years, it has also attracted attention as a power source for electric vehicles from the viewpoint of environmental issues.

[0003] In view of the recent use of lead-acid batteries for automobiles, it is considered that these batteries are beginning to be used in new use environments. That is, many electric devices such as an air conditioner, an audio device, and a car navigation system are employed, and the load on the lead storage battery is increasing. In addition, the engine room becomes smaller to secure living space and reduce air resistance,
With the increase in the output of the engine, the temperature inside the engine room has become considerably high, and lead-acid batteries have been exposed to this high temperature.

[0004] In addition, even for a battery that requires a large current by repeating deep charging and discharging such as for an electric vehicle, the situation where the battery is placed is extremely compact in order to maximize the indoor space. Heat is more likely to accumulate, and batteries are exposed to higher temperatures.

In general, an organic expander, an inorganic expander (usually barium sulfate is used) and carbon are added to a negative electrode plate for a lead-acid battery, and each contributes to the improvement of various performances of the negative electrode plate for a lead-acid battery. I have. Among these, the organic expander uses by-products generally obtained during pulp production called lignin, and suppresses the coarsening of the negative electrode active material (spongy lead) that progresses with the charge and discharge of the battery, The active material is miniaturized by suppressing the contraction of the active material, thereby preventing the discharge capacity of the negative electrode plate, particularly the high-rate discharge capacity, from lowering.

However, it has been difficult to obtain satisfactory life performance with lignin currently used for high temperature use such as changes in the use environment of the above-mentioned lead acid battery for automobiles and application to electric vehicles. This is because when lignin is exposed to high temperatures, it decomposes or elutes into the electrolyte,
It is considered that the amount decreases. For this reason, there has been a demand for a negative electrode plate that has a small decrease in life performance even at high temperatures, that is, an organic expander that is not easily decomposed or eluted.

As organic expanders having excellent high-temperature characteristics, for example, JP-A-2-234352 and JP-A-4-6.
No. 5062 describes the use of a derivative of naphthalenesulfonic acid. However, it is hard to say that the performance is sufficient especially in a use condition where the temperature is high.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problem that the life of the negative electrode plate at high temperatures is reduced.

[0009]

The present invention is characterized in that a bisphenol and a sulfite or a formaldehyde condensate of an amino acid are added to a negative electrode active material for a lead storage battery. The formaldehyde condensate of the bisphenol with a sulfite or an amino acid has a weight average molecular weight of 0.3 to 3.0 × 10 ⁴ . A formaldehyde condensate of the bisphenol and a sulfite or an amino acid is added together with a derivative of a naphthalenesulfonic acid formaldehyde condensate. A formaldehyde condensate of the bisphenol and a sulfite or an amino acid is added together with lignin or a derivative thereof.
It is characterized in that the formaldehyde condensate of bisphenols and sulfite or amino acid is bisphenol A / sodium sulfite / formaldehyde condensate.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below based on embodiments.

Example 1 First, the following polycondensate was prepared as an organic expander to be added to a negative electrode. The formaldehyde condensate of bisphenols and sulfites or amino acids of the present invention is a condensate described in JP-A-04-352751, and according to the examples of the publication, bisphenol A / sodium sulfite / formaldehyde condensate (Hereinafter referred to as bisphenolsulfonic acid polymer) was synthesized. The structure of this substance is shown in Formula 1.

The weight average molecular weight can be adjusted to 0.1 × 10 ⁴ , 0.3 ×
10 ⁴ , 0.5 × 10 ⁴ , 1.0 × 10 ⁴ , 3.0 × 1
There were obtained 6 types of O ⁴ and 5.0 × 10 ⁴ . Similarly, a bisphenol A / sodium glutamate / formaldehyde condensate (hereinafter referred to as bisphenol carboxylic acid polymer: weight average molecular weight 1.0 × 10 ⁴ ) was synthesized. The structure is shown in two equations.

[0013]

Embedded image

Embedded image The weight average molecular weight is GPC (gel permeation chromatography, standard substance polyethylene glycol)
Was measured. Sulfite lignin Na salt (Vanilex N manufactured by Nippon Paper Co., Ltd., hereinafter referred to as lignin) and Na salt of a naphthalenesulfonic acid formaldehyde condensate (Vaniol HD-100 manufactured by Nippon Paper Co., Ltd.) (Hereinafter referred to as NSF).

Each of these organic expanders was added in an amount of 0.2% by weight to obtain nine kinds of negative electrode plates shown in Table 1. That is, 100 kg of lead powder having an apparent specific gravity of about 1.8 g / cm ³ containing about 75% by weight of PbO, and a specific gravity of about 1.15
About 20 dm ³ of diluted sulfuric acid, 0.7% by weight of an inorganic expander (barium sulfate), 0.2% by weight of carbon, and 0.2% by weight of an organic expander as additives, and after filling in a lattice. After aging and drying, negative plates having different organic expanders were obtained. The addition amounts of barium sulfate and carbon can be changed depending on the purpose of use of the battery, and the range is usually 0 to 2% by weight for barium sulfate and 0 to 2% by weight for carbon. Also, the amount of the organic expander to be added can be changed, but usually 0.1 to 0.4% by weight for the cycle application, and a smaller amount for the float or trickle application.

[0015]

[Table 1] Although not used in the present embodiment, when the grid is coarse or when plate strength is required, a plate reinforcing material such as a synthetic organic fiber may be added. This addition amount is usually 0.0
5 to 0.2%.

The negative electrode plate 1 uses lignin as an organic expander, and the negative electrode plate 2 uses NSF. The negative plates 3 to 8 use bisphenolsulfonic acid polymers of various molecular weights, and the negative plate 9 uses a bisphenolcarboxylic acid polymer.

In this embodiment, the negative electrode grid contains P
Although an expanded grid made of b-0.07 wt% Ca-0.5 wt% Sn alloy was used, a cast grid usually used in lead-acid batteries may be used. Also, lattice alloys
In addition to the Pb-Ca (-Sn) -based alloy, a Pb-Sb-based alloy or the like can be used.

On the other hand, the cathode paste contains about 75 PbO.
Lead powder 100 having an apparent specific gravity of about 1.8 g / cm ³ including weight%
A mixture obtained by kneading diluted sulfuric acid having a specific gravity of about 1.15 with respect to kg at a rate of about 25 dm ³ was used. In this positive electrode paste,
Lead tin may be added for the purpose of improving the formation efficiency, or synthetic fiber having a length of about 2 to 5 mm may be added for improving the strength of the electrode plate. The amount of synthetic fiber added is 0.1 to
About 0.3% by weight is appropriate.

The positive electrode paste was filled in a lead alloy grid, aged and dried to obtain a positive electrode plate. Note that the positive electrode grid used in this example was Pb-0.07% by weight Ca.
It was a cast grid made of -1.5 wt% Sn alloy,
The cost can be reduced by using the expanded grid. Pb-Ca (-
A Pb-Sb-based alloy or the like can be used in addition to the Sn) -based alloy.

These negative and positive plates and the separator were laminated, and nine types of sealed lead-acid batteries for electric vehicles having a nominal voltage of 12 V and a nominal capacity of 50 Ah were produced as shown in Table 2. The separator used was a glass separator made of fine glass fibers having a diameter of about 0.8 μm, and the separator and the positive and negative electrode plates were impregnated and held with an electrolytic solution to form a so-called sealed battery in which no leakage occurred. . The specific gravity of sulfuric acid after the formation of the battery tank was 1.28 at 20 ° C.

First, a three-hour rate discharge test was performed using these nine types of lead storage batteries. This means that the electrolyte temperature is 30
The discharge was performed at a rate of 3 hours at ± 2 ° C. to a discharge termination voltage of 9.9 V, and the discharge capacity was examined. Next, a high rate discharge test was performed. In this method, the battery was discharged at an electrolyte temperature of 30 ± 2 ° C. at 150 A to a discharge termination voltage of 6 V, and its discharge capacity was examined. The test results are shown in Table 2.

[0022]

[Table 2] The three-hour rate capacity of the battery C using the bisphenolsulfonic acid polymer having a weight average molecular weight of 0.1 × 10 ⁴ was 10% or more lower than that of the other batteries. This battery also has a low high-rate discharge capacity, which is considered to be due to the low molecular weight and the formation of a dense film on the surface of the negative electrode active material, so that the initial formation was not sufficient. All of the others having a weight average molecular weight of 0.3 × 10 ⁴ or more exhibited good 3 hour rate and high rate discharge capacity.

Thereafter, it was subjected to a life test for electric vehicles.
That is, assuming that the battery ambient temperature is 50 ° C.
The battery is charged for 2.4 hours at a time rate current, and then charged for 10 hours.
This was performed for 9 hours with a time current, and after repeating this 50 times, the battery capacity was examined by discharging at a rate of 3 hours. These are 50
In the above capacity survey, the 3-hour rate capacity was 80 times the rated capacity.
%.

FIG. 1 shows the test results. Batteries A and B using lignin and NSF, which are conventional products, reached a life of 250 and 300 cycles, respectively. The cause of the life was a decrease in the surface area of the negative electrode active material. This was thought to be because the added organic expander was decomposed by the reduction reaction at the time of charging or by sulfuric acid as the electrolytic solution, and the effect was reduced. Battery C using bisphenolsulfonic acid polymer having a low weight average molecular weight of 0.1 × 10 ⁴
Showed better performance than the conventional product, but the capacity transition was slightly inferior. Since lead sulfate was accumulated in the negative electrode active material after the end of the life test, it was considered that the cause was that the charge receiving performance was low. Conversely, Battery H using the bisphenolsulfonic acid polymer having a high molecular weight of 5 × 10 ⁴ showed 300 cycles and a life performance equivalent to that of the NSF product. The molecular weight was very high, and the dispersibility in the negative electrode active material was inferior to others. Weight average molecular weight of 0.3 to 3.0 ×
Batteries D to G using 10 ⁴ bisphenolsulfonic acid polymers showed excellent life performance of 400 cycles or more. The causes of the capacity decrease were a decrease in the surface area of the negative electrode plate and the deterioration of the positive electrode plate.

The battery I using the bisphenol carboxylic acid polymer also exhibited a life performance of 400 cycles or more. The causes of the capacity decrease were a decrease in the surface area of the negative electrode plate and the deterioration of the positive electrode plate as in the batteries D to G using the bisphenolsulfonic acid polymer.

As described above, by using a bisphenolsulfonic acid polymer or a bisphenolcarboxylic acid polymer, preferably a bisphenolsulfonic acid polymer having a weight average molecular weight of 0.3 to 3.0 × 10 ⁴ as an organic expander, it is possible to obtain a conventional 1.5 wt. It was found that a negative electrode plate having more than twice the life performance was obtained.

Example 2 Lignin and NSF conventionally used as organic expanders were mixed with bisphenolsulfonic acid polymer, which is an excellent organic expander, in various ratios to prepare four kinds of mixed organic expanders. The effect on battery performance was investigated.

Using these organic expanders, four types of negative plates indicated by symbols 10 to 13 shown in Table 3 were obtained. Also,
For comparison, three kinds of negative electrode plates to which lignin, NSF and bisphenolsulfonic acid polymer were individually added were also prepared. In each negative electrode plate, the organic expander was added at 0.2%. Using these negative plates, seven types of three-hour rate nominal capacities of 50 shown in Table 4 were used in the same manner as in Example 1.
Ah-type sealed lead-acid batteries for electric vehicles were manufactured, and their three-hour rate capacity and high rate discharge capacity were investigated.

[0029]

[Table 3] The test results are shown in Table 4. The three-hour rate discharge capacity was not significantly different for any of the batteries, and was higher than the nominal capacity. On the other hand, the batteries J to M using the mixed organic expander were superior in the high rate discharge capacity to the batteries using each of them alone. Although the cause is not clear, it is probable that the mixing resulted in a synergy that was not known before.

[0030]

[Table 4] The results of subjecting these batteries to a life test for an electric vehicle battery in the same manner as in Example 1 are shown in FIG. Batteries J to M using the mixed organic expander for the negative electrode plate exhibited excellent capacity even after 500 cycles of discontinuing the test. In all the batteries, the cause of the decrease in capacity was thought to be due to the negative electrode plate, but no significant deterioration was observed in the negative electrode plates of these batteries. Although the cause is not clear as in the case of the increase in the high rate discharge capacity, it is considered that mixing causes a synergistic effect which has not been known so far. In particular, the effect seemed to be great when mixed with NSF.

As described above, the life performance at a high temperature of the negative electrode plate to which lignin and NSF conventionally used as an organic expander and bisphenolsulfonic acid polymer which is an excellent organic expander are added is significantly different from that of the negative electrode plate. It was superior to the above, and an unexpected synergistic effect appeared on the life performance of the battery when both were mixed.

This effect was similarly observed when the bisphenol carboxylic acid polymer was mixed with lignin and NSF.

Example 3 In Examples 1 and 2, bisphenol A / sodium sulfite / formaldehyde condensate and bisphenol A / sodium glutamate / formaldehyde condensate were used as examples of the formaldehyde condensate of bisphenols and sulfites or amino acids. .

Here, as other examples of the formaldehyde condensate of bisphenols and sulfites or amino acids, bisphenol AF / sodium sulfite / formaldehyde condensate (weight average molecular weight 1.0 × 10 ⁴ ) having a structure represented by Formula 3; The effect of a bisphenol F / sodium sulfite / formaldehyde condensate (weight average molecular weight 1.0 × 10 ⁴ ) having a structure represented by Formula ⁴ on battery performance was examined. The battery manufacturing method and the test method are the same as those in Examples 1 and 2.

[0035]

Embedded image

Embedded image As a result, the battery using the negative electrode plate to which bisphenol AF / sodium sulfite / formaldehyde condensate or bisphenol F / sodium sulfite / formaldehyde condensate was added was the bisphenol A. The initial performance and life performance of the battery using sodium sulfite / formaldehyde condensate or bisphenol A / sodium glutamate / formaldehyde condensate were equal to or better than those of the battery. Thus, it is considered that a formaldehyde condensate of a bisphenol and a sulfite or an amino acid can provide the effects of the present invention.

In the first and second embodiments, the results using the sealed type lead-acid battery were described in detail. However, the same effect was obtained in the open-type lead-acid battery used for a battery for an automobile or the like.

In this example, the results of the cycle life test were described in detail. In addition, in the float charge life test, the life performance of the negative electrode plate according to the present invention was clearly superior to the control product. .

As described above, the effect of the present invention does not change depending on the type and test method of the lead storage battery, but can be applied to various lead storage batteries and can be used for various purposes.

[0039]

As described above, the negative electrode plate for a lead storage battery according to the present invention is prepared by adding a formaldehyde condensate of a bisphenol and a sulfite or an amino acid, preferably having a weight average molecular weight of 0.3 to 3.0 × 10 3. ⁴ , more preferably added together with a naphthalenesulfonic acid formaldehyde condensate or lignin, and more preferably, the bisphenols and a sulfite or an amino acid formaldehyde condensate are bisphenol A / sodium sulfite / By being a formaldehyde condensate, it is possible to prevent a decrease in life performance especially at a high temperature, and its industrial value is extremely large.

[Brief description of the drawings]

FIG. 1 is a view showing the results of a life test at 50 ° C. (Example 1).

FIG. 2 is a diagram showing a result of a life test at 50 ° C. (Example 2).

Claims (5)

[Claims] 1. A negative electrode plate for a lead-acid battery, wherein a bisphenol and a sulfite or a formaldehyde condensate of an amino acid are added to the active material. 2. The negative electrode plate for a lead-acid battery according to claim 1, wherein the formaldehyde condensate of the bisphenol and a sulfite or an amino acid has a weight average molecular weight of 0.3 to 3.0 × 10 ⁴ . 3. The negative electrode for a lead storage battery according to claim 1, wherein the formaldehyde condensate of the bisphenol and a sulfite or an amino acid is added together with a derivative of a naphthalenesulfonic acid formaldehyde condensate. Board. 4. The negative electrode plate for a lead-acid battery according to claim 1, wherein said bisphenols and a sulfite or a formaldehyde condensate of an amino acid are added together with lignin or a derivative thereof. 5. The negative electrode plate for a lead storage battery according to claim 1, wherein the formaldehyde condensate of a bisphenol and a sulfite or an amino acid is bisphenol A / sodium sulfite / formaldehyde condensate.