JPH09213336A - Lead-acid storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead-acid storage battery having good acceptance for changing operation by adding a specific amount of certain component(s) to a negative electrode active material, and thereby holding the effect of an expander continuously for a long time. SOLUTION: 0.5-1.0wt.% lignin is added to a negative electrode active material of a lead acid storage battery concerned, and thereto also 1.0-2.0wt.% carbon is added. Batteries No.1 to No.4 using negative electrode plate with increased contents of lignin and carbon do not exhibit a steep drop of the capacity in the initial period of lifetime, which has been usual with a battery using conventioanl negative electrode plate, nor exhibit drop of the capacity due to insufficient charging, and they can exert a good low-temp., high-rate discharging performance to the final stage of the lifetime.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an improvement of a negative electrode plate of a lead storage battery.

[0002]

2. Description of the Related Art Conventionally, several kinds of additives have been added to a negative electrode active material of a lead storage battery. One of them is lignin, which is a by-product in the production of pulp, used in combination with barium sulfate as an expander (shrinkproof agent) for the purpose of improving low-temperature high-rate discharge performance. About 4% by weight is added. In addition to the above, carbon is added in an amount of about 0.1 to 0.3% by weight for the purpose of improving current efficiency during chemical conversion.

[0003] Lignin is adsorbed on the surface of the negative electrode active material,
It is considered to have the effect of increasing the size of the lead sulfate crystals generated during discharge and suppressing the decrease in the specific surface area of the active material during charging, which results in high rate discharge performance at low temperatures and life performance. It is believed to be improved.

[0004]

However, the lignin adsorbed on the surface of the active material is gradually eluted into the electrolytic solution from the negative electrode plate during charging / discharging, and the further eluted lignin is oxidized on the positive electrode plate to form carbon dioxide. However, there is a problem that the effect does not last for a long time. In addition, when a large amount of lignin is added in order to maintain the effect for a long period of time, there is a problem that charge acceptability is lowered, charge is insufficient, and the capacity is rather lowered.

[0005]

According to the present invention, 0.5 to 1.0% by weight of lignin and 1.0 to 2.0% by weight of carbon are added to a negative electrode active material.
It is intended to provide a lead-acid battery which has a long-lasting effect of an expander and is excellent in charge acceptance. That is, a large amount of lignin is added to the negative electrode active material to decrease the charge acceptability, so by adding a large amount of carbon to supplement the charge acceptability, the effect of the expander is prolonged without decreasing the charge acceptability. It is intended to be maintained for a period.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on Examples. In order to clarify the effect of the present invention, the inventor manufactured an automobile battery with a 5 hour rate capacity of 35 Ah, in which the amounts of lignin and carbon added to the negative electrode active material were variously changed, and the battery was manufactured according to JIS standard (JIS D 5301). The life cycle test by

The amounts of lignin and carbon in the manufactured battery are shown in Table 1. Battery No. 1 to No. No. 4 is a battery according to the present invention. 1 is a battery in which 0.5% of lignin and 1.0% of carbon are added to the negative electrode active material,
Battery No. 2 is a battery containing 0.5% lignin and 2.0% carbon, and battery No. No. 3 is a battery containing 1.0% lignin and 1.0% carbon, No. 3 4 is lignin 1.0
%, Carbon 2.0% is added. For comparison, the battery No. The conventional lignin as 5 is 0.2
%, Carbon with 0.1% added, battery No. 6, a battery with 1.0% lignin and 0.1% carbon added,
Battery No. 7 as lignin 0.2%, carbon 1.0
%, The battery with the added amount was manufactured and subjected to the test.

In this example, sodium lignin sulfonate was used as the lignin, acetylene black was used as the carbon, and barium sulfate was added to all the negative electrode active materials at a concentration of 0.
5% was added. The same positive electrode plate was used.
(All addition amounts are weight% based on the amount of the negative electrode active material)

[0009]

[Table 1] The test results are shown in FIGS. FIG. 1 shows the 20 A discharge performance during the life cycle, and FIG. 2 shows the low temperature high rate discharge (150 A discharge at −15 ° C.) performance during the life cycle. In the conventional battery (Battery N0.5), the low-temperature high-rate discharge capacity is remarkably reduced from the beginning of its life. This is because lignin eluted from the negative electrode plate during the life cycle. In addition, the battery (battery No. 6) in which only the lignin was increased to 1.0% had poor charge acceptance and became insufficiently charged.
Both the 20 A discharge and the low temperature high rate discharge gradually decreased in capacity from the beginning of the cycle. On the other hand, the battery containing only the increased amount of carbon (Battery No. 7) showed almost the same capacity transition as the conventional product in both 20 A discharge and low temperature high rate discharge.

On the other hand, the batteries (Batteries No. 1 to No. 4) using the negative electrode plate according to the present invention in which the amount of lignin was increased and the amount of carbon was also increased are found in the batteries using the conventional negative electrode plate. There was no sudden decrease in capacity at the beginning of life, and there was no capacity decrease due to insufficient charging, and good low-temperature high-rate discharge performance was exhibited until the end of life.

The same effect can be expected if the amounts of lignin and carbon are further increased and added, but as the amount of the additive is increased, the amount of the active material per volume is decreased and the capacity is rather reduced. The amount of lignin is 0.1
%, Carbon is preferably 2.0% or less.

[0012]

INDUSTRIAL APPLICABILITY As described above, the lead storage battery to which the additive according to the present invention is added is superior in low temperature and high rate discharge life performance to the conventional lead storage battery, and its industrial value is enormous.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing a comparison of 20 A discharge performance during a cycle life test.

FIG. 2 is a characteristic diagram showing a comparison of −15 ° C. and 150 A discharge performance during a cycle life test.

Claims (1)

[Claims] 1. A lead acid battery, wherein 0.5 to 1.0% by weight of lignin and 1.0 to 2.0% by weight of carbon are added to the negative electrode active material.