JPH09147872A - Negative electrode plate for lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of the service life of a negative electrode plate at a high temperature by containing a mixture of a polymer of styrene sulfonic acid (a derivative) and lignin. SOLUTION: After lead powder containing PbO, dilute sulfuric acid, an inorganic expander 0 to 2wt.%, an organic expander composed of a mixture of a polymer of styrene sulfonic acid (a derivative) and Na salt type lignin of sulfite lignin obtained by a sulfite method and a plate reinforcing agent 0.5 to 0.2wt.% according to its necessity are kneaded together, it is filled in a lattice body, and is aged, and is dried.

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 including starting and lighting of automobiles, as well as small capacity consumers and large capacity stationary applications. In recent years, it has also attracted attention as a power source for electric vehicles from the viewpoint of environmental issues.

Looking at the recent usage of lead acid batteries for automobiles, it is considered that these batteries are being put under new usage environment. That is, many electric components such as an air conditioner, an audio device, and a car navigation system are adopted, and a load on the lead storage battery is increasing. In addition, the engine room becomes smaller in order to secure living space and air resistance, and due to the higher output of the engine, the temperature inside the engine room is considerably high, and the lead storage battery is also exposed to this high temperature. Are becoming available.

Further, even in the case of a battery that requires a large current by repeating deep charge and discharge such as for an electric vehicle, the condition of the battery can be kept very compact in order to maximize the indoor space, and the battery temperature Is exposed to high temperatures.

Generally, an organic expander (expander: shrink-proofing agent), an inorganic expander (barium sulfate) and carbon are added to the negative electrode plate for a lead storage battery.
Each contributes to various performance improvements of the negative electrode plate for lead acid batteries. Among them, the organic expander generally uses a by-product called lignin, which is obtained during pulp production, and suppresses the growth of the negative electrode active material (lead metal) that progresses as the battery is charged and discharged to suppress the active material. To prevent the active material from becoming finer and prevent the discharge capacity of the negative electrode plate, particularly the high rate discharge capacity, from decreasing.

However, it has been difficult to obtain a satisfactory life performance with the lignin currently used for high temperature use such as change of 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 in the electrolyte,
It is considered that the amount decreases. Therefore, there has been a demand for a negative electrode plate with less deterioration in life performance even at high temperatures, that is, an organic expander that is difficult to decompose or elute.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problem of deterioration of the life performance of a negative electrode plate under high temperature, and a styrene sulfonic acid or its derivative is used as a negative electrode plate for a lead storage battery. It is characterized by adding a mixture of a polymer and lignin, and preferably, the lignin is an Na salt form of sulfite lignin obtained by the sulfite method or an acid form of kraft lignin obtained by the kraft method. It is characterized by.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A negative electrode plate for a lead storage battery according to the present invention is prepared by kneading a lead powder containing a mixture of a polymer of styrene sulfonic acid or its derivative and lignin with diluted sulfuric acid to prepare an active material paste. After filling the
It is prepared by aging and drying. The lignin used here is preferably the sodium salt form of sulfite lignin obtained by the sulfite method or the acid form of craft lignin obtained by the craft method. With such a configuration, it is possible to prevent the deterioration of the battery life performance especially at high temperatures.

[0009]

【Example】

Example 1 Details of the present invention will be described below based on examples.

First, the sodium salt of sulfite lignin produced by the sulfite method is used as the lignin, and the Na salt of polystyrenesulfonic acid (average molecular weight: about 10,000) is used as an example of a polymer of styrenesulfonic acid or its derivative.
Was prepared. These were used alone or mixed to prepare 5 kinds of organic expanders.

Table 1 was prepared using these organic expanders.
Five types of negative electrode plates shown in were obtained.

[0012]

[Table 1] That is, the apparent specific gravity of PbO is about 1.
100 kg of lead powder of 8 g / cm ³ , about 20 liters of dilute sulfuric acid having a specific gravity of about 1.15, 0.7% by weight of an inorganic expander (barium sulfate) as an additive, and 0.1% of carbon.
After 2% by weight and an organic expander were kneaded and filled in a grid, aging and drying were carried out to obtain five types of negative electrode plates having different organic expanders. 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,
Although not used in this example, a plate reinforcing agent such as a synthetic organic fiber may be added when the grid is coarse or when the plate strength is required. This amount is usually 0.0
It is 5 to 0.2%.

Here, the negative electrode plate 1 uses the Na salt of sulfite lignin produced by the sulfite method as an organic expander alone, and the negative electrode plate 5 uses the Na salt of polystyrenesulfonic acid alone. It is a thing.
The negative electrode plates 2, 3 and 4 are made of sulfite lignin Na.
A salt and a Na salt of polystyrene sulfonic acid,
An organic expander mixed at 3: 1, 1: 1 and 1: 3 was used. The addition amount of the organic expander is 0.2% by weight in terms of solid content, regardless of whether it is a single substance or a mixed product.

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

On the other hand, the positive electrode paste contains about 75 PbO.
100% lead powder with an apparent specific gravity of about 1.8 g / cm ³
A mixture obtained by kneading dilute sulfuric acid having a specific gravity of about 1.15 with respect to kg at a ratio of about 25 liters was used. Lead oxide may be added to the positive electrode paste for the purpose of improving the conversion 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 was 0.
About 1 to 0.3% by weight is suitable.

A lead alloy grid was filled with the above positive electrode paste and aged and dried to obtain a positive electrode plate. The lattice used in this example is Pb-0.07 wt% Ca-.
Although it was a cast lattice made of 1.5 wt% Sn alloy, the cost can be reduced by using the expanded lattice. In addition, the lattice alloy used for the positive electrode is a Pb-Ca (-Sn) -based alloy or Pb-S that is usually used for lead-acid batteries.
A b-based alloy or the like can be used.

The negative electrode plate, the positive electrode plate and the separator are laminated to obtain a nominal voltage of 12 V and 5 V described in JIS D5301.
As shown in Table 2, five types (A to E) of 55D23 type automobile batteries having a nominal rate of hourly capacity of 48 Ah were manufactured. The specific gravity of sulfuric acid after battery case formation was 1.28 at 20 ° C.

The separator of the positive and negative plates has a diameter of about 10 to 20 μm.
A glass mat formed by making m of glass fiber and a separator formed by making silica powder, glass fiber, resin fiber and the like were laminated together.

Using these five types of lead-acid batteries, first, JI
It was subjected to the charge acceptability test described in SD5301. That is, a fully charged battery is heated at room temperature for 5 hours at a rate current (9.6).
After discharging at A) for 2.5 hours and leaving it for 12 hours or more at an ambient temperature of 0 ± 2 ° C, the terminal voltage 1 at the ambient temperature.
The battery was charged at 4.4 ± 0.1 V, and the current at 10 minutes was measured.

Next, the 5-hour rate capacity and high rate discharge capacity described in JIS D5301 were investigated. In the 5-hour rate discharge test, the electrolyte was discharged at a temperature of 25 ± 2 ° C. with a 5-hour rate current to a discharge end voltage of 10.5 V, and the discharge capacity was investigated. In addition, the high rate discharge test, the electrolyte temperature -15 ±
Discharge to discharge end voltage 6V at 300A at 1 ° C,
The discharge capacity was investigated. The results of these tests are also shown in Table 2.

[0021]

[Table 2] Charge acceptability and 5 hour rate discharge capacity of any battery A ~
E was also almost the same. The high rate discharge capacity is higher than that of batteries A and E, which are conventional products in which the sodium salt of sulfite lignin and the sodium salt of polystyrene sulfonic acid are used alone, respectively. The batteries B, C and D according to the present invention, which were prepared by mixing and using, were excellent. Thus, by mixing the Na salt of sulfite lignin and the Na salt of polystyrene sulfonic acid, an unexpected synergistic effect appeared in the initial performance of the battery.

Then, using the same battery, JIS D5
The test was performed by changing the light load life test described in 301.
The main changes are that the storage battery ambient temperature is 75 ° C. ± 2 ° C., and the number of charge / discharge repetitions until the end of life is 500.

That is, when the storage battery ambient temperature is 75 ° C. ± 2 ° C., discharging is performed at a current of 25 ± 0.05 A for 4 minutes, and subsequently charging is performed at a terminal voltage of 14.8 ± 0.03 V (limit current 25 A) for 10 minutes. After repeating this 500 times, it is left at the ambient temperature for 48 hours, and the judgment current 356
The battery was discharged at A for 30 seconds and the voltage was measured at 30 seconds. After that, charge the terminal voltage 14.8 ± 0.03V (limit current 2
5A) for 10 minutes.
This operation was repeated until the second voltage became 7.2 V or less.

The test results are shown in FIG. Na salt of sulfite lignin and Na of polystyrene sulfonate
Conventional batteries A and E using salt individually
Had a lifespan of about 4000 cycles and about 3500 cycles, respectively, whereas N of sulfite lignin
The batteries B, C, and D according to the present invention, which were prepared by mixing the a salt and the Na salt of polystyrene sulfonic acid, were all 600
It had a life performance of 0 cycles or more.

When these batteries were disassembled after the life test, it was considered that the batteries A and E both had a large amount of contraction of the negative electrode active material, which resulted in the end of life. on the other hand,
Batteries B, C and D were disassembled after the life test was discontinued at 6000 cycles, but there were only a few signs of deterioration on the negative electrode plate of these batteries, and the lattice corrosion that is the deterioration of the positive electrode plate caused the discharge voltage drop. Seemed to be.

Thus, Na of sulfite lignin
The high-temperature life performance of the negative electrode plate containing a mixture of salt and Na salt of polystyrene sulfonic acid added is superior to that of conventional products, and by mixing both, an unexpected synergistic effect appears in the life performance of the battery. It was (Example 2) Lignin is roughly classified into kraft lignin and sulphite lignin due to the difference in production method.
It can be classified into Na salt (type) and acid type depending on the final treatment method. Therefore, these four types of lignin were mixed with Na salt of polystyrene sulfonic acid to prepare four types of mixed organic expanders, which were added to the negative electrode, and the effect on the battery performance was examined.

For comparison, Kraft lignin Na salt (
Type) and an acid type, a sulfite lignin Na salt (type) and an acid type, and a conventional battery using a Na salt of polystyrenesulfonic acid as a simple substance were subjected to the test.

Nine kinds of negative electrode plates shown in Table 3 were obtained using these organic expanders. The negative electrode plates 1, 3 and 5 have the same formulation as the negative electrode plates 1, 3 and 5 of Example 1, respectively.

[0029]

[Table 3] From these, in the same manner as in Example 1, nine types of 55-hour battery type 55D23 lead-acid batteries having a nominal capacity of 48 Ah shown in Table 4 were manufactured, and the charge acceptance test 5 hour rate capacity and high rate discharge capacity described in JIS D5301. investigated.

The test results are also shown in Table 4.

[0031]

[Table 4] Charge acceptability and 5 hour rate discharge capacity are all batteries A,
C and E to K were also almost the same. On the other hand, the high rate discharge capacity is the battery A, which is a conventional product using each lignin and Na salt of polystyrene sulfonic acid alone.
Compared to F to H and E, the batteries C and I to K according to the present invention, in which various lignins and Na salt of polystyrene sulfonic acid were mixed and used, were superior.

These batteries were tested according to JIS 1
The results of the light load life test at 75 ° C. according to D5301 are shown in FIG. Conventional batteries A, F, G, H and E using Kraft lignin Na salt (type) and acid type, sulfite lignin Na salt (type) and acid type, and Na salt of polystyrene sulfonic acid respectively, are
All of them had reached the end of their lives by 4,500 cycles. It was considered that these batteries had a long contraction due to the large contraction of the negative electrode active material.

On the other hand, the batteries C and I to K according to the present invention, which were used by mixing various lignins and the Na salt of polystyrene sulfonic acid, all had a life performance of 6000 cycles or more without much difference. In particular, Battery C used by mixing Na salt of polystyrene sulfonic acid and Na salt of sulfite lignin and Battery K used by mixing Na salt of polystyrene sulfonic acid and Kraft lignin acid type were 6
Even after 000 cycles, the degree of deterioration of the negative electrode plate was remarkably small. Battery I using a mixture of Na salt of polystyrene sulfonic acid and sulfite lignin acid type and battery J using a mixture of Na salt of polystyrene sulfonic acid and Kraft lignin Na salt shrink slightly to the negative electrode plate. Was recognized.

As described above, in particular, a mixture of Na salt of sulfite lignin and Na salt of polystyrene sulfonate or a mixture of acid form of kraft lignin and Na salt of polystyrene sulfonate is added as an organic expander at a high temperature. The battery life performance was markedly superior to that of the conventional product, and by mixing the two, an unexpected synergistic effect appeared in the battery life performance.

In Examples 1 and 2, the Na salt of polystyrene sulfonic acid was used as an example of the polymer of styrene sulfonic acid or its derivative, but the same synergistic effect can be obtained by using other derivatives or polymers having different molecular weights. It was confirmed that it was obtained.

In Examples 1 and 2, the effect of the present invention was described on the test results using the open type automobile battery. The mat containing mainly fine glass fibers was impregnated with and retained in the electrolytic solution to prevent leakage. The same effect was obtained also in a liquefied so-called sealed lead acid battery.

Although the results of the light load life test at high temperature are described in detail in the present embodiment, the polymer of styrene sulfonic acid or its derivative is also used in the cycle test with deep charge / discharge and the float charge life test. The life performance of the negative electrode plate containing the mixture of lignin and lignin was clearly superior to that of the conventional product.

As described above, the effects of the present invention described in Embodiments 1 and 2 do not change depending on the type of lead storage battery and the test method, and can be used for various lead storage batteries and various applications.

[0039]

As described above, the negative electrode plate for a lead storage battery according to the present invention contains a mixture of a polymer of styrene sulfonic acid or its derivative and lignin, and preferably the lignin obtained by the sulfite method is used. By using the sodium salt form of phytolignin or the acid form of kraft lignin obtained by the kraft method, it is possible to prevent the life performance from being deteriorated particularly at high temperatures, and its industrial value is extremely great.

[Brief description of the drawings]

FIG. 1 is a diagram showing the results of a JIS light load life test at 75 ° C.

FIG. 2 is a diagram showing the results of a JIS light load life test at 75 ° C.

Claims (3)

[Claims] 1. A negative electrode plate for a lead storage battery, wherein a mixture of a polymer of styrene sulfonic acid or its derivative and lignin is added. 2. The negative electrode plate for a lead storage battery according to claim 1, wherein the lignin is a sodium salt type of sulfite lignin obtained by a sulfite method. 3. The negative electrode plate for a lead storage battery according to claim 1, wherein the lignin is an acid form of kraft lignin obtained by the kraft method.